United States
Agency
Office of theV\s(6ciate. Dire
Compliance Assurance ana'
Region 6, DallasjTX-75202,
' EPA 906-C-05-001
^Division i March 2005 j,
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Environi
ental Resource Stewards
(TERS) •lwl
Texas Ecolpgica|>Assess
Pfofeol (TEAR):
lot Pf©j4ct Report
Flying in a "V" formation saves energy, wrwle enabling farther flights and greater
communication. This is a "natural" exampleotoUeJiynergy" promoted by TERS.
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Texas Environmental Resource Stewards (TERS):
Texas Ecological Assessment Protocol (TEAP) Results
Pilot Project
Prepared by
U.S. Environmental Protection Agency Region 6, Texas Parks and Wildlife
Department, and The Nature Conservancy
S. L. Osowski, J. Danielson, S. Schwelling, D. German, S. Gilbert, D.
Lueckenhoff, D. Parrish, A. K. Ludeke, and J. Bergan
March 1, 2005
EPA Publication Number: 906-C-05-001
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Citation Info:
Osowski, S. L., J. Danielson, S. Schwelling, D. German, M. Swan, D. Lueckenhoff, D. Fairish,
A. K. Ludeke, and J. Bergan. 2005. Texas Environmental Resource Stewards (TERS) Texas
Ecological Assessment Protocol (TEAP) Results, Pilot Project Report. Report Number EPA-
906-C-05-001. US Environmental Protection Agency Region 6, Dallas, TX.
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The Texas Environmental Resource Stewards (TERS) was formed by the Executive Leaders of
various federal and state agencies to collaborate on common ecosystem management and
regulatory streamlining issues. The Texas Ecological Assessment Protocol (TEAP) is a product
of the TERS effort which analyzes existing broad-scale electronic data to identify important
ecological areas in Texas that should be avoided or protected, if possible. This report
communicates the initial results of this new tool. Agencies and the public will be able to use this
information to aid in project planning and scientific research, ultimately leading to better
environmental assessments, improved understanding, and enhanced decision-making. The
TEAP is not designed to be used to make final decisions on individual projects, but rather to
serve as a general screening tool to allow environmental professionals to focus limited resources
to protect critical ecological areas and to give the public an overview of environmental
conditions in Texas.
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TC1Q
-—-^
U.S.
US Army Corps
of Engineers
Southwestern Division
s^The Nature
{Conservancy.
€»J»
Director
and Division
US EnvironmentaWrtJtSCtTon Agency Region 6
Robert L. Cool
Executive Director
Texas Parks and Wildlife Department
i
Gary Loew
Director, Programs Directorate
Southwestern Division
U.S. Armycffp§4)f
Texas Administrator V
US Fish and Service
C.D.(Dan)%ag«ifiVE.
Texas Division Administrator
Federal Highway Administration
W. Behrens, P. E.
Executive Director
David C. P. E,
Chief Engineer
Texas Commission on Environmental
Quality
f larrfes Bergan, Ph.D.
V"O}fector of Science and Stewardship
The Nature Conservancy
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Table of Contents
Chapter Page
EXECUTIVE SUMMARY 1
Background 1
Diversity 2
Rarity 2
Sustainability 3
Actions 4
1.0 INTRODUCTION 9
1.1 TERS History 9
1.2 Texas Ecological Assessment Protocol (TEAP) Goals 11
1.3 Background 12
1.3.1 Geographical Information System (GIS)-Based Assessments 12
1.3.2 Ecoregion Delineation 14
1.3.2.1 Types of Ecoregion Delineation 15
1.3.3 Ecological Theory Used in TEAP 15
1.3.3.1 Diversity 20
1.3.3.1.1 Appropriateness of Land Cover 20
1.3.3.1.2 Contiguous Size of Undeveloped Land 20
1.3.3.1.3 Shannon Land Cover Diversity Index 21
1.3.3.1.4 Ecologically Significant Stream Segments 22
1.3.3.2 Rarity 23
1.3.3.2.1 Vegetation Rarity 24
1.3.3.2.2 Natural Heritage Rank 24
1.3.3.2.3 Taxonomic Richness 25
1.3.3.2.4 Rare Species Richness 25
1.3.3.3 Sustainabilitv 26
1.3.3.3.1 Contiguous Land Cover Type 26
1.3.3.3.2 Regularity of Ecosystem Boundary 27
1.3.3.3.3 Appropriateness of Land Cover 30
1.3.3.3.4 Waterway Obstruction 30
1.3.3.3.5 Road Density 30
1.3.3.3.6 Airport Noise 31
1.3.3.3.7 Superfund National Priority List (NPU and
State Superfund Sites 31
1.3.3.3.8 Water Quality 32
1.3.3.3.9 Air Quality 32
1.3.3.3.10 RCRA. TSD. Corrective Action and
State VCP Sites 33
1.3.3.3.11 Urban/Agriculture Disturbance 34
1.3.4 TEAP Development 34
1.3.4.1 TPWD Conservation Planning 35
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1.3.4.2 The Nature Conservancy Ecoregional Planning Process 35
1.3.4.3 EPA Region 5 CrEAM 37
2. 0 METHODS 44
2.1 Base Unit Selection 44
2.2 TEAP Sub-layers and Layers 47
2.2.1 Diversity Layer 47
2.2.1.1 Appropriateness of Land Cover 47
2.2.1.2 Contiguous Size of Undeveloped Land 57
2.2.1.3 Shannon Land Cover Diversity Index 57
2.2.1.4 Ecologically Significant Stream Segments 58
2.2.2 Rarity Layer 59
2.2.2.1 Vegetation Rarity 59
2.2.2.2 Natural Heritage Rank 60
2.2.2.3 Taxonomic Richness 62
2.2.2.4 Rare Species Richness 63
2.2.3 Sustainability Layer 63
2.2.3.1 Contiguous Land Cover Type 63
2.2.3.2 Regularity of Ecosystem Boundary 64
2.2.3.3 Appropriateness of Land Cover 65
2.2.3.4 Waterway Obstruction 66
2.2.3.5 Road Density 66
2.2.3.6 Airport Noise 68
2.2.3.7 Superfund NPL and State Superfund Sites 69
2.2.3.8 Water Quality 69
2.2.3.9 Air Quality 69
2.2.3.10 RCRA. TSD. Corrective Action and State VCP Sites 70
2.2.3.11 Urban/Agriculture Disturbance 70
2.2.4 Accuracy Assessment 71
3.0 RESULTS 74
3.1 Diversity Layer 74
3.2 Rarity Layer 74
3.3 Sustainability Layer 77
3.4 Composite Layer 77
3.4.1 Ecoregion Composites 80
3.4.1.1 Southern High Plains 80
3.4.1.2 Texas High Plains 80
3.4.1.3 Rolling Plains 83
3.4.1.4 Rio Grande Plain 83
3.4.1.5RedbedPlains 83
3.4.1.6 Cross Timbers and Prairie 83
3.4.1.7 Oak Woods and Prairies 88
3.4.1.8BlacklandPrairie 88
3.4.1.9 Mid Coastal Plains. Western Section 88
3.4.1.10 Coastal Plains and Flatwoods. Western Gulf Section 88
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3.4.1.11 Edwards Plateau 92
3.4.1.12 Stockton Plateau 92
3.4.1.13 Chihuahuan Desert Basin and Range 92
3.4.1.14 Sacramento-Manzano Mountain 97
3.4.1.15 Louisiana Coast Prairies and Marshes 97
3.4.1.16 Eastern Gulf Prairies and Marshes 97
3.4.1.17 Central Gulf Prairies and Marshes 97
3.4.1.18 Southern Gulf Prairies and Marshes 102
3.4.2 Overlays 102
3.4.3 Accuracy Assessment 102
4.0 DISCUSSION 112
4.1 Data Limitations 113
4.2 Accuracy Assessment 117
4.3 Conservation 118
5.0 CONCLUSIONS 120
5.1 Streamlining 120
5.2 Next Steps 120
6.0 ACKNOWLEDGMENTS 122
7.0 REFERENCES 123
APPENDIX A: Descriptions of Bailey's Ecoregions 134
Southeastern Mixed Forest 140
Mid Coastal Plains. Western (Section 23 IE) 140
Geomorphology 140
Lithology and Stratigraphy 140
Soil Taxa 140
Potential Natural Vegetation 141
Fauna 141
Climate 141
Surface Water Characteristics 141
Disturbance Regimes 141
Land Use 141
Eastern Gulf Prairies and Marshes (Section 23 IF) 141
Geomorphology 141
Lithology and Stratigraphy 142
Soil Taxa 142
Potential Natural Vegetation 142
Fauna 143
Climate 143
Surface Water Characteristics 143
Disturbance Regimes 143
Land Use 143
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Outer Coastal Plain Mixed Forest 143
Louisiana Coast Prairies and Marshes (Section 232E) 143
Geomorphology 143
Lithology and Stratigraphy 144
Soil Taxa 144
Potential Natural Vegetation 144
Fauna 144
Climate 145
Surface Water Characteristics 145
Disturbance Regimes 145
Land Use 145
Coastal Plains and Flatwoods. Western Gulf (Section 232F) 145
Geomorphology 145
Lithology and Stratigraphy 146
Soil Taxa 146
Potential Natural Vegetation 146
Fauna 146
Climate 146
Surface Water Characteristics 147
Disturbance Regimes 147
Land Use 147
Prairie Parkland (Subtropical) 147
Cross Timbers and Prairies (Section 255 A) 147
Geomorphology 147
Lithology and Stratigraphy 148
Soil Taxa 148
Potential Natural Vegetation 148
Fauna 148
Climate 148
Surface Water Characteristics 148
Disturbance Regimes 149
Land Use 149
Blackland Prairies (Section 255B) 149
Geomorphology 149
Lithology and Stratigraphy 149
Soil Taxa 149
Potential Natural Vegetation 150
Fauna 150
Climate 150
Disturbance Regimes 150
Land Use 150
Oak Woods and Prairies (Section 255O 150
Geomorphology 150
Lithology and Stratigraphy 151
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Soil Taxa 151
Potential Natural Vegetation 151
Fauna 151
Climate 152
Surface Water Characteristics 152
Disturbance Regimes 152
Land Use 152
Central Gulf Prairies and Marshes (Section 25 5D} 152
Geomorphology 152
Lithology and Stratigraphy 153
Soil Taxa 153
Potential Natural Vegetation 153
Fauna 153
Climate 153
Surface Water Characteristics 153
Disturbance Regimes 154
Land Use 154
Great Plains Steppe and Shrub 154
Redbed Plains (Section 311 A} 154
Geomorphology 154
Lithology and Stratigraphy 155
Soil Taxa 155
Potential Natural Vegetation 155
Fauna 155
Climate 155
Surface Water Characteristics 155
Disturbance Regimes 155
Land Use 155
Southwest Plateau and Plains Dry Steppe and Shrub 156
Texas High Plains (Section 315B) 156
Geomorphology 156
Lithology and Stratigraphy 156
Soil Taxa 156
Potential Natural Vegetation 156
Fauna 156
Climate 157
Surface Water Characteristics 157
Disturbance Regimes 157
Land Use 157
Rolling Plains (Section 315O 158
Geomorphology 158
Lithology and Stratigraphy 158
Soil Taxa 158
Potential Natural Vegetation 159
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Fauna 159
Climate 159
Surface Water Characteristics 159
Disturbance Regimes 159
Land Use 159
Edwards Plateau (Section 315D} 159
Geomorphology 159
Lithology and Stratigraphy 160
Soil Taxa 160
Potential Natural Vegetation 160
Fauna 160
Climate 161
Surface Water Characteristics 161
Disturbance Regimes 161
Land Use 161
Rio Grande Plain (Section 315E} 161
Geomorphology 161
Lithology and Stratigraphy 161
Soil Taxa 161
Potential Natural Vegetation 162
Fauna 162
Climate 163
Surface Water Characteristics 163
Disturbance Regimes 163
Land Use 163
Southern Gulf Prairies and Marshes (Section 315F) 163
Geomorphology 163
Lithology and Stratigraphy 164
Soil Taxa 164
Potential Natural Vegetation 164
Fauna 164
Climate 164
Surface Water Characteristics 164
Disturbance Regimes 165
Land Use 165
Arizona-New Mexico Mountains Semi-Desert - Open Woodland -
Coniferous Forest - Alpine Meadow 165
Sacramento-Manzano Mountain (Section M313B) 165
Geomorphology 165
Lithology and Stratigraphy 165
Soil Taxa 166
Potential Natural Vegetation 166
Climate 166
Surface Water Characteristics 166
Disturbance Regimes 166
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Cultural Ecology 166
Chihuahuan Semi-Desert 167
Basin and Range (Section 321A) 167
Geomorphology 167
Lithology and Stratigraphy 168
Soil Taxa 168
Potential Natural Vegetation 168
Climate 168
Surface Water Characteristics 168
Disturbance Regimes 169
Land Use 169
Cultural Ecology 169
Stockton Plateau (Section 32IE} 169
Geomorphology 169
Lithology and Stratigraphy 170
Soil Taxa 170
Potential Natural Vegetation 170
Fauna 170
Climate 171
Surface Water Characteristics 171
Disturbance Regimes 171
Land Use 171
Great Plains-Palouse Dry Steppe 171
Southern High Plains (Section 33 IE} 171
Geomorphology 171
Lithology and Stratigraphy 172
Soil Taxa 172
Potential Natural Vegetation 172
Fauna 172
Climate 172
Surface Water Characteristics 172
Land Use 172
APPENDIX B: Individual sub-layer maps 173
Diversity layer 176
Rarity layer 177
Sustainability layer 179
Figures 181
APPENDIX C: List of Acronyms 200
APPENDIX D: List of contributors 205
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List of Tables
Table 1. TPWD planning results. Priority ecoregions for conservation efforts 36
Table 2. Relationship of the EPA SAB framework ecological attributes to EPA Region 5
CrEAM and TEAP 39
Table3. Summary of TEAP layers 48
Table 4. GIS data layers used for TEAP 53
Table 5. Kuchler (1964) PNV classifications and corresponding NLCD land cover types 55
List of Figures
Figure A. Map of the diversity layer with ecoregion boundaries 5
FigureB. Map of the rarity layer with ecoregion boundaries 6
Figure C. Map of the sustainability layer with ecoregion boundaries 7
Figure D. Composite map with ecoregion boundaries 8
Figure 1. Map of Bailey's ecoregion sections 16
Figure 2. Map of Omernik ecoregions 17
Figure3. Map of Gould's vegetation types 18
Figure 4. Map of Texas natural areas 19
Figure 5. Map of the diversity layer with ecoregion boundaries. This map is a
composite of four sub-layers (Figures B1-B4) 75
Figure 6. Map of the rarity layer with ecoregion boundaries. This map is a
composite of four sub-layers (Figures B5-B8) 76
Figure 7. Map of the sustainability layer with ecoregion boundaries. This map is a
composite of eleven sub-layers (Figures B9-B19) 78
Figure 8. Composite map with ecoregion boundaries. This map is a composite
of the diversity layer (Figure 5\ rarity layer (Figure 6). and
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sustainability layer (Figure 7) 79
Figure 9. Southern High Plains composite map. A separate figure (Figure 8)
shows the entire state 81
Figure 10. Texas High Plains composite map. A separate figure (Figure 8)
shows the entire state 82
Figure 11. Rolling Plains composite map. A separate figure (Figure 8)
shows the entire state 84
Figure 12. Rio Grande Plain composite map. A separate figure (Figure 8)
shows the entire state 85
Figure 13. Redbed Plains composite map. A separate figure (Figure 8)
shows the entire state 86
Figure 14. Cross Timbers and Prairie composite map. A separate figure (Figure 8)
shows the entire state 87
Figure 15. Oak Woods and Prairies composite map. A separate figure (Figure 8)
shows the entire state 89
Figure 16. Blackland Prairie composite map. A separate figure (Figure 8)
shows the entire state 90
Figure 17. Mid Coastal Plains Western Section composite map. A separate figure
(Figure 8) shows the entire state 91
Figure 18. Coastal Plains and Flatwoods Western Gulf Section composite map.
A separate figure (Figure 8) shows the entire state 93
Figure 19. Edwards Plateau composite map. A separate figure (Figure 8)
shows the entire state 94
Figure 20. Stockton Plateau composite map. A separate figure (Figure 8)
shows the entire state 95
Figure 21. Chihuahuan Desert Basin and Range composite map. A separate
figure (Figure 8) shows the entire state 96
Figure 22. Sacramento-Manzano Mountain composite map. A separate figure
(Figure 8) shows the entire state 98
Figure 23. Louisiana Coast Prairies and Marshes composite map. A separate
figure (Figure 8) shows the entire state 99
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Figure 24. Eastern Gulf Prairies and Marshes composite map. A separate
figure (Figure 8) shows the entire state 100
Figure 25. Central Gulf Prairies and Marshes composite map. A separate
figure (Figure 8) shows the entire state 101
Figure 26. Southern Gulf Prairies and Marshes composite map. A separate
figure (Figure 8) shows the entire state 103
Figure 27. Composite map with public lands overlay. Public lands include
National and State Parks, National Forests and Grasslands,
Department of Defense lands, and National Wildlife Refuges 104
Figure 28. Composite map with transportation corridors overlay. IH69 and
Trans Texas Corridor are included 105
Figure 29. Composite map with watershed boundary overlay 106
Figure 30. Map depicting areas used for the accuracy assessment 107
Figure 31. a) Statewide frequencies of TEAP composite scores (by class) that
occur inside and outside TNC portfolio; b) statewide frequencies
expressed as a percentage of TEAP composite scores occurring
inside and outside TNC portfolio 108
Figure 32. Map of proposed IH69 corridor depicting areas used for
the accuracy assessment 110
Figure 33. a) IH69 corridor frequencies of TEAP composite scores (by class)
that occur inside and outside TNC portfolio; b) IH69 corridor
frequencies expressed as a percentage of TEAP composite scores
occurring inside and outside TNC portfolio Ill
Figure Bl. Map of diversity sub-layer: appropriateness of land cover. This map
is used to produce the map of the diversity layer (Figure 5) 181
Figure B2. Map of diversity sub-layer: contiguous size of undeveloped land.
This map is used to produce the map of the diversity layer (Figure 5) 182
Figure B3. Map of diversity sub-layer: Shannon land cover diversity index.
This map is used to produce the map of the diversity layer (Figure 5) 183
Figure B4. Map of diversity sub-layer: ecologically significant stream segments.
This map is used to produce the map of the diversity layer (Figure 5) 184
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Figure B5. Map of rarity sub-layer: vegetation rarity. This map is
used to produce the map of the rarity layer (Figure 6) 185
Figure B6. Map of rarity sub-layer: natural heritage rank. This map
is used to produce the map of the rarity layer (Figure 6) 186
Figure B7. Map of rarity sub-layer: taxonomic richness. This map
is used to produce the map of the rarity layer (Figure 6) 187
Figure B8. Map of rarity sub-layer: rare species richness. This map is
used to produce the map of the rarity layer (Figure 6) 188
Figure B9. Map of sustainability sub-layer: contiguous land cover type. This
map is used to produce the map of the sustainability layer (Figure 6) 189
Figure BIO. Map of sustainability sub-layer: regularity of ecosystem boundary. This
map is used to produce the map of the sustainability layer (Figure 7) 190
Figure Bll. Map of sustainability sub-layer: appropriateness of land cover. This
map is used to produce the map of the sustainability layer (Figure 7) 191
FigureB 12. Map of sustainability sub-layer: waterway obstruction. This map
is used to produce the map of the sustainability layer (Figure 7) 192
FigureB 13. Map of sustainability sub-layer: road density. This map is
used to produce the map of the sustainability layer (Figure 7) 193
FigureB 14. Map of sustainability sub-layer: airport noise. This map is
used to produce the map of the sustainability layer (Figure 7) 194
FigureB 15. Map of sustainability sub-layer: Superfund National Priority
List and state Superfund Sites. This map is used to produce the map
of the sustainability layer (Figure 7) 195
FigureB 16. Map of sustainability sub-layer: water quality. This map is
used to produce the map of the sustainability layer (Figure 7) 196
Figure B17. Map of sustainability sub-layer: air quality. This map is
used to produce the map of the sustainability layer (Figure 7) 197
FigureB 18. Map of sustainability sub-layer: RCRA TSD, corrective action and
state VCP sites. This map is used to produce the map of the
sustainability layer (Figure 7) 198
FigureB 19. Map of sustainability sub-layer: urban/agriculture disturbance. This
map is used to produce the map of the sustainability layer (Figure 7) 199
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EXECUTIVE SUMMARY
Background
Texas Environmental Resource Stewards (TERS) was established in July 2002 to seek
greater federal and state interagency collaboration on identifying and supporting joint priorities,
particularly regarding transportation issues. Leaders from participating agencies identified
common interests and target activities for collaborative ecosystem management of benefit to
each agency. Common interests included identification of ecologically important natural
resource areas (wetland, aquatic, and terrestrial) for avoidance, or potential compensatory
mitigation, preservation, or restoration; "streamlining" of regulatory processes; early
identification of some National Environmental Policy Act (NEPA) requirements in project
planning; and analysis of cumulative impacts. The TERS executives developed a vision which
included the following actions:
Improve mutual understanding
Use collective knowledge to support decision-making
Strive for synergism
The initial approach to achieving a portion of the TERS vision was to develop an ecosystem
approach to organize strategies that achieve effective and measurable environmental results, and
jointly communicate the results to the public. The initial goals of TERS were to identify
ecologically important areas, identify potential mitigation areas, and streamline regulatory
processes. This report serves to communicate progress on the first goal: the ecological
assessment and identification of ecologically important resources in the state of Texas.
1
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Technical experts from participating TERS agencies agreed to (1) develop a scientifically
valid, ecosystem prioritization protocol for Texas; (2) apply this protocol to existing, available
data using GIS: and (3) demonstrate the protocol to identify areas of highest ecological
importance in Texas. The Texas Ecological Assessment Protocol (TEAP) relies on a previously
developed methodology and consists of collecting and analyzing existing electronic data
available statewide, which was used to evaluate the following three ecological criteria:
1. Diversity What areas have the most diverse land cover?
2. Rarity What areas have the highest number of rare species
and land cover types?
3. Sustainability What areas can sustain ecosystems now and in the
future?
Chapter 2 of the full report provides details of TEAP. The results of the analysis for each layer
within each ecoregion are summarized below (Figures A-C). The eighteen ecoregion sections
developed by Bailey (1994) were used.
Diversity (Figure A): The diversity map shows higher diversity in west Texas
(Chihuahuan Desert Basin and Range ecoregion). There are areas of high diversity in the
southern portion of the Rolling Plains ecoregion, and the Rio Grande Plain ecoregion.
Rarity (Figure B): The rarity map shows the areas of highest rarity are in the Stockton
Plateau and the Coastal Plains and Flatwoods Western Gulf Section ecoregions. In
2
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addition, areas in the Chihuahuan Desert Basin and Range, Edward's Plateau, Oak
Woods and Prairies, and the southern portion of the Rio Grande Plain ecoregion show
moderately high levels of rarity.
Sustainability (Figure C): Figure C shows the combination of all eleven layers in a map
representing sustainability. There are only a few highly sustainable (top 1%, 10%)
locations in the Chihuahuan Desert Basin and Range, Stockton Plateau, southern Rio
Grande Plain, southern Rolling Plains, and a few other areas in Texas. The more
sustainable areas occur where there are fewer human disturbance activities. Most of the
population lives in the eastern half of the state. Thus, the Cross Timbers and Prairies,
Central Gulf Prairies and Marshes, Mid Coastal Plains Western Section, and Blackland
Prairies ecoregions show the lowest sustainability.
These three layers were combined into a composite map that shows where ecologically
important areas occur in Texas (Figure D). The top 1% highly ecologically important areas in
Texas are highlighted in red. Most of the ecologically important (1%, 10%) areas are located in
Chihuahuan Desert Basin and Range, Stockton Plateau, and Rio Grande Plain ecoregions. Other
areas that have high or moderately high ecologically important areas are the Edwards Plateau
and the southern portion of the Mid Coastal Plains Western Section. Conversely, the most
threatened areas are in the Blackland Prairies, Oak Woods and Prairies, Central Gulf Prairies and
Marshes, and Louisiana/Eastern Gulf Prairies and Marshes ecoregions which TEAP indicates
have the least sustainable ecological areas. The Nature Conservancy (The Conservancy)
performed an independent accuracy assessment on the TEAP comparing the composite scores
3
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and The Conservancy portfolio sites. This assessment showed, in general, that those areas
ranked as highly important ecologically by TEAP corresponded to areas identified as very
ecologically important in The Conservancy portfolio. Field investigation would be necessary to
better determine the accuracy of locations that had low TEAP composite scores.
TEAP was applied to rapidly assess the entire Texas landscape by ecoregion through the
use of a statewide GIS grid. The results of TEAP provide a tool for use in project planning and
for reducing very large corridors to more manageable areas for more detailed field investigation.
Identification of ecologically important areas in each ecoregion can be used as a tool to support
ecosystem-driven mitigation sequencing (avoidance of impacts, minimization, and then
compensation) and conservation planning throughout the state. TEAP can also be used to find
high quality habitat remnants in all ecoregions in Texas. The TEAP is intended to be a
supplemental tool for agency use, not to circumvent or replace agency policies, processes, or
regulations.
Actions
Updated analyses using 2002 land cover data can be performed once this data is made
available in a GIS format. In addition, several other databases (e.g., pipelines, oil and gas wells)
were suggested for incorporation. These databases, as well as modifications to the current
protocol, can be made in subsequent iterations. TEAP will be reevaluated every 2 to 3 years
when new land cover and other data become available. Therefore, TEAP can be used to identify
trends in ecological condition by comparing results from previous years.
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Southern High Plains
Oak Woods
ries
Mid Coastal
Plains, Western
Coastal Plains
and Flatwoods,
Western Gulf
Louisiana Coast
Prairies and
Marshes
Top 1 % (More Diverse)
2-10%
11 - 25%
26 - 50%
51 -100% (Less Diverse)
Rio Grande Plain
200
Miles
Figure A. Map of the diversity layer with ecoregion boundaries. This map is a composite of
four sub-layers: appropriateness of land cover, contiguous size of undeveloped land, Shannon
land cover diversity index, and ecologically significant stream segments.
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Southern High Plains
Mid Coastal
Plains, Western
Cross Timbers Oak Woods
and Prairies
Coastal Plains
and Flatwoods,
Western Gulf
Louisiana Coast
Prairies and
Marshes
•
Top1%
2-10%
1 1 - 25%
26 - 50%
51 -100%
(More Rare)
A
•\
L
r
(Less Rare)
200
Miles
Figure B. Map of the rarity layer with ecoregion boundaries. This map is a composite of four
sub-layers: vegetation rarity, natural heritage rank, taxonomic richness, and rare species richness.
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Southern High Plain:
Oak Woods
and Prairies
Mid Coastal
Plains, Western
Top1%
2-10%
11 - 25%
26 - 50%
51 -100% (Less Sustainable)
Coastal Plains
and Flatwoods,
Western Gulf
Louisiana Coast
Prairies and
Marshes
200
Miles
Figure C. Map of the sustainability layer with ecoregion boundaries. This map is a composite of
eleven sub-layers: contiguous land cover type; regularity of ecosystem boundary;
appropriateness of land cover; waterway obstruction; road density; airport noise; Superfund NPL
and state Superfund sites; water quality; air quality; RCRA TSD. corrective action, and state
VCP sites; and urban/agriculture disturbance.
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Southern High Plains
Oak Woods
ries
Miles
Figure D. Composite map with ecoregion boundaries. This map is a composite of the diversity layer
(Figure A), rarity layer (Figure BX and sustainability layer (Figure C).
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1.0 INTRODUCTION
1.1 TERS History
Texas Environmental Resource Stewards (TERS) was established by various state and
federal resource agencies in July 2002 to create greater interagency collaboration on identifying
and supporting joint priorities in Texas. Leaders from the U.S. Environmental Protection
Agency (EPA), U.S. Army Corps of Engineers (USAGE! U.S. Fish and Wildlife Service
(FWS), Federal Highway Administration (FHWA), Texas Commission on Environmental
Quality (TCEQX Texas Parks and Wildlife Department (TPWD), Texas Department of
Transportation (TXDOT), and the Texas Governor's Office met to develop a vision and
objectives for TERS. Other target participants, such as the General Land Office (GLO), Texas
Water Development Board (TWDB), Texas Historical Commission (THC), Texas Department of
Agriculture, U.S. Forest Service (USFSX and non-governmental organizations (NGO's), such as
The Nature Conservancy of Texas (The Conservancy) were also identified as possibly having an
interest in supporting the TERS vision and goals. The Conservancy was subsequently asked to
participate because of its expertise in producing ecoregional portfolios of important conservation
areas.
Participating agencies identified common interests and target activities for collaborative
ecosystem evaluation and management in Texas. Common interests and uses included
identification of ecologically important areas (wetland, aquatic, and terrestrial) to be targeted for
avoidance, minimization of impacts, or compensatory mitigation (enhancement, preservation, or
restoration); "streamlining" of regulatory processes; generation of additional data to support
regulatory decisions; early assistance with National Environmental Policy Act (NEPA) planning
9
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and analysis, project development and review; greater collaboration on environmental planning
and public outreach; analysis of cumulative impacts (also including direct, indirect, and
secondary impacts); preservation and improvement of surface water, ground water, and air
quality; identification of ecologically important habitats (wetland, aquatic, terrestrial,
endangered species); and providing improved indicators of biodiversity health and ecosystem
functionality (including fragmentation effects). Streamlining, as defined in this report, is a
cooperative and coordinated process that assures timely, cost effective, and environmentally
sound planning and project development based on concurrent, multi-agency review. Executive
Order (EO) 13274, Environmental Stewardship and Transportation Infrastructure Project
Reviews, suggests agencies take actions to expedite environmental reviews and permit decisions
specifically for transportation projects.
The following vision was developed for TERS:
Improve mutual understanding of agency needs and expectations.
Use collective knowledge and expertise to broaden perspectives and support
decision-making affecting regional environmental, economic and societal
policies, issues, and trends.
Strive for synergism, so that the total effect is greater than the sum of individual
agency efforts.
The initial goals of TERS were to identify ecologically important areas, identify
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potential mitigation areas, and streamline regulatory processes. The TERS agency
representatives chose to focus solely on environmental and ecological conditions, not historical
and cultural resources. This report is the initial step in meeting the first TERS goal: the
ecological assessment and identification of ecologically important resources in Texas.
1.2 Texas Ecological Assessment Protocol (TEAP) Goals
The approach to achieving the TERS vision was to identify and collaborate on common
priorities using an ecosystem approach to organize strategies that achieve effective and
measurable environmental results, and to jointly communicate the results to the public. The
TEAP is the method the TERS Steering Committee agreed to (1) develop a scientifically valid,
ecosystem-based process for Texas; (2) apply this process to existing available data and
information through the use of Geographical Information Systems (GIS): and (3) demonstrate
the process for identifying ecologically important resources throughout Texas. TERS
participants were asked to identify potential uses for the TEAP within each agency. However, at
the present time, no specific commitments or plans for the TEAP have been made.
The TEAP is a screening level, rapid assessment tool using existing electronic data
available statewide. The TEAP is an "ecoregional" assessment, applied to an entire state.
Therefore, it is general in nature and design. It is a planning tool and screening-level assessment
that should lead users to progressively narrow the scope of analysis. It is not an all-
encompassing predictive model for each land cover type, species, etc.
The potential intended use of the results of the TEAP include: 1) use in the NEPA
planning process (scoping, alternatives development, etc.), 2) use in streamlining the
authorization process for large projects (such as transportation) by narrowing the study corridor
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necessary for further field investigation, and 3) use in mitigation discussions to avoid
ecologically important areas, minimize impacts to those areas, and compensate for unavoidable
impacts. This list of intended uses is not exhaustive, nor all inclusive. The TEAP is not
designed to take the place of agency policies and procedures. It is a supplemental information
tool aiding in agency decision making. The initial TEAP product is a CD with the three main
layers and composite layer data in GIS format. The final version of this report will be included
on the CD.
1.3 Background
1.3.1 Geographical Information System (GIS)-Based Assessments
GIS is used in the development of assessment and geospatial screening tools not only
because of its spatial data visualization abilities (i.e., maps of different data layers, coverages,
landscape level, etc.), but also because of its modeling and analysis functions, including
landscape metrics (e.g. FRAGSTATS), and other calculations such as population density,
hydrological function. Given the direction of the TERS executives, it was apparent that GIS
would be useful for TEAP. GIS is a vital research and assessment tool (Dale et al. 1994.
Treweek and Veitch 1996. O'Neill etal. 1999. Iverson et al. 2001. Clevenger et al. 2002. Ji and
Leeberg 2002). When used at the landscape level, GIS can identify and prioritize areas for
protection to enable animal movement by evaluating different land management uses (Clevenger
et al. 20021
Regionally-scaled projects, such as those that use the ecoregion (Mysz et al. 2000) or
watershed (Dickert and Tuttle 1985. Tinker etal. 1998. Espejeletal. 1999. Steiner et al. 2000a.
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Steiner et al. 2000b. Serveiss 2002) as a base unit, have become more common with the advent
and subsequent increase in the use of spatial analysis tools such as GIS. These tools have
inspired scientists concerned about landscape level patterns and their effect on terrestrial and
aquatic communities (Steiner et al. 2000a. Jones et al. 2001. H. John Heinz III Center for
Science. Economics and the Environment 2002). Assessments, whether landscape- or
geographically-based, are more holistic than assessments performed locally, or those based on
political boundaries, because of their ability to relate potentially unrelated factors (Miller et al.
1998) and for comparisons at other scales. For example, several geographic units can be
aggregated (Montgomery et al. 1995).
Geographically-driven approaches have also been used to analyze environmental
problems (e.g. nonpoint source water pollution, regional studies) that do not fit into traditional
programs or assessment methods (Boughton et al. 1999. Serveiss 2002.) as well as those
problems needing a holistic or comprehensive analysis such as broad assessments like TEAP.
Landscape-level assessments also lead to improved intergovernmental coordination and more
informed decision-making on regulatory and management initiatives (Steiner et al. 2000a.
Serveiss 2002). Better interagency coordination and cooperation are goals of the TERS group.
As with TEAP. most geospatial tools use some sort of criteria or factors to evaluate the
data layers used in the assessment (Karydis 1996. Steiner et al. 2000b. Store and Kangas 2001.
Xiang2001). These ranks, or scores, simplify the analysis (Serveiss 2002). normalize disparate
data sets onto one nominal scale (Wickham et al. 1999. Clevenger et al. 2002). and provide an
easily understandable format to communicate the results to various audiences (Theobald et al.
2000). These 'scores' are helpful in comparing various aspects of projects since the 'score'
represents the relative value of one alternative to another (Abbruzzesee and Leibowitz 1997.
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Wickham et al. 1999. Steiner et al. 2000b). These scoring systems may represent the difference
between an ideal state of the environment and reality (Tran et al. 2002).
1.3.2 Ecoregion Delineation
TEAP uses eighteen ecoregion sections (hereafter referred to as ecoregions) developed
by Bailey (1994) as the base unit for calculation. Further details on the process of base unit
selection are provided in the Methods chapter. Ecoregions illuminate ecosystem patterns at
multiple scales, aiding the visualization of differences between ecosystems. They can be defined
as regions of relative homogeneity in ecological systems (Griffith et al. 1999). Most ecoregions
include minimally impacted areas that can be used to define reference conditions necessary to
provide a basis for comparison to impacted areas. Since multiple areas within an ecoregion are
relatively similar, they should respond similarly to stresses or management actions. Thus,
ecoregions are appropriate areas for extrapolation of monitoring, including statistical sampling
or research results (Bryce et all996. Harrison et al. 2000). Ecoregions can be used as reporting
frameworks that clarify patterns of environmental data (such as nutrient transport) reflecting
both natural and human influences. Griffith et al. (1999) contend that ecoregion frameworks are
highly effective tools for accomplishing comprehensive and integrative management approaches
due to their depiction of the whole mosaic of ecosystem components - biotic and abiotic,
terrestrial and aquatic, including human-related factors that affect water quality and quantity
(major components of watershed assessment).
Ecoregions allow the development of management strategies appropriate to regional
expectations. They define areas where standardized management practices can be applied after
being proven in individual sites or watersheds.
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1.3.2.1 Types of Ecoregion Delineation
Bailey (1985. 1987. 1994. 1996) developed a multi-tiered, broad-scale, hierarchical
system of ecoregions at a scale of 1:7,500,000 based on numerous environmental variables
(Figure 1). The first two tiers are based on combinations of climate, physiography, topography
and soils which were used to provide a general description of the ecosystem geography. The
ecoregion system can be used to address environmental issues that transcend agency, watershed,
and political boundaries and borders. Details of the ecoregion sections in Texas can be found in
Appendix A. Other delineations of ecoregions include Omernik (1987. 1995) (Figure 2). Gould
(1975) (Figure 3). and Lyndon B. Johnson School of Public Affairs (1978) (Figure 4). The
Omernik (1987) system constructs ecoregions based on perceived patterns of a combination of
causal and integrative factors including land use, land surface form, potential natural vegetation,
and soils (Omernik 1987). Bailey (1994. 1996) and Omernik (1987) plan to merge ecoregion
maps. The map of vegetative types of Texas (Gould 1975) provides a checklist and ecological
summary of Texas plants (Figure 3).
An interdisciplinary team of scientists and laymen developed a system of classifying
Texas into natural regions (Lyndon B. Johnson School of Public Affairs 1978). They recognized
that regions distinguished by physiographic or biologic differences could be readily identified by
scientists and local citizens, with the goal of preserving elements of Texas' natural diversity
(Figure 4).
1.3.3 Ecological Theory Used in TEAP
TEAP divides nineteen individual measures from databases into sub-layers which
comprise three separate main layers. These main layers are diversity, rarity, and sustainability.
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Southern High Plains
Sacramento-
Monzano
Mountain
Central Gulf
Prairi^HB
Marshes •,
Southern Gulf
Prairies and
Marshes
Coastal Plains
and Flatwoods,
Western Gulf
Louisiana Coast
Prairies and
Marshes
Eastern Gulf
Prairies and
Marshes
Figure 1. Map of Bailey's ecoregion sections (Bailey 1994).
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Western
High Plains
Western
High
Plains
southwestern
Central Oklahoma/
Texas Plain
Arizona/
New Mexico
Mtns
South
Central
Plains
Southern Deserts
Central Texas Plateau
Southern
Texas
Plains
Figure 2. Map of Omernik ecoregions (Omernik 1987).
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High Plains r\l Rolling Plains
I Miles
0 37.5 75 150 225 300
Figure 3. Map of Gould's vegetation types (Gould 1975).
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Figure 4. Map of Texas natural areas (Lyndon B. Johnson School of Public Affairs 1978).
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1.3.3.1 Diversity
The diversity layer shows land cover continuity and diversity in Texas. This layer
consists of four sub-layers: (1) appropriateness of land cover, (2) contiguous size of undeveloped
area, (3) Shannon land cover diversity, and (4) ecologically significant stream segments.
The diversity layer demonstrates an important fundamental ecological principle: the
species-area relationship. The species-area relationship states that larger areas have higher
diversity and/or species abundance than smaller areas (Diamond and May 1976. Schafer 1990.
Harte and Kinzig 1997). There are several hypotheses to explain the species-area relationship.
The one pertinent for TEAP is the habitat diversity hypothesis, which states that increases in the
number of types of habitat in an area increases the number of niches able to be filled, therefore
larger areas would have more species or land cover types (Jonson and Fahrig 1997). Other
species-area hypotheses include island biogeography (MacArthur and Wilson 1967) and the
random sample hypothesis (Arrhenius 1921).
1.3.3.1.1 Appropriateness of Land Cover. Appropriateness of land cover describes the predicted
natural vegetation under no human influence (Kuchler 1964) and compares it to the current
vegetation cover. The rationale for including this measure in the diversity layer is twofold: 1)
the area is ecologically stable and resistant to disturbance if pre-settlement vegetation and
current vegetation types are the same, and 2) it is a surrogate for species diversity.
1.3.3.1.2 Contiguous Size of Undeveloped Land. Contiguous size of undeveloped land is
calculated using the theory that the larger the contiguous area of undeveloped land, the higher
the diversity (MacArthur and Wilson 1967. Dale and Haeuber 2000).
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There are two similar measures calculated in the diversity and sustainability layers.
"Contiguous area of undeveloped area" is entitled and calculated slightly differently in the
diversity layer compared to the sustainability layer. In the diversity layer, all undeveloped land
cover types that are adjacent to each other are lumped into one polygon. In the sustainability
layer, the individual, undeveloped land cover types (that made up this larger polygon in the
diversity layer) are calculated separately. In diversity, the question being answered is, "how
extensive are the areas of undeveloped land?" In sustainability, the question answered is, "How
extensive are the cover types that make up the areas of undeveloped land?"
All adjacent undeveloped land cover is merged into one polygon (e.g., forest adjacent to
wetland adjacent to grassland). One polygon could have any number of cover types. For
example, one contiguous polygon may consist of three different, undeveloped land cover types.
As long as they are all undeveloped and adjacent to each other, the contiguous size of
undeveloped land sub-layer is calculated as one polygon (until interrupted by a developed cover
type).
1.3.3.1.3 Shannon Land Cover Diversity Index. The Shannon land cover diversity index
calculates the diversity, in terms of land cover types, for each of the contiguous polygons
calculated in the previous section. The Shannon index is an established method used to measure
ecological (species) diversity (richness and evenness) (Begon etal. 1986). It usually calculates
the proportion of individuals of a population related to the total number of individuals, but used
here to calculate the proportion of land cover types, related to the total number of land cover
types. Other ecological diversity measures used in landscape assessment are discussed in
Herzog et al. (20011
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The Shannon land cover diversity index does not view land cover diversity the same way
as the contiguous size of undeveloped land sub-layer. In general, the Shannon land cover
diversity index shows how many specific land cover types there are in these contiguous area
polygons and how they are dispersed.
A low value for Shannon land cover diversity index means there are fewer undeveloped
land cover types and that they may be clumped, compared to a more evenly dispersed pattern
within the geographical boundary. A high value would indicate that there are several
undeveloped land cover types that are more evenly dispersed throughout the geographic area.
The idea that the Shannon land cover diversity index should increase with less contiguous area is
not exactly true because the measures are somewhat independent. Logic indicates that it may be
more likely that there are more land cover types in larger areas (polygons), but that is not
necessarily the case. For example, there could be a large unbroken tract of desert in west Texas.
1.3.3.1.4 Ecologically Significant Stream Segments. Significant stream segments (Norris and
Linum 1999. El-Hage and Moulton 2000a. Norris and Linum 2000a. El-Hage and Moulton
2000b. Norris and Linum 2000b. El-Hage and Moulton 2001) represent natural systems that are
increasingly rare habitat and is the aquatic equivalent of the contiguous size of undeveloped land
sub-layer. Significant stream segments are ecologically unique areas determined by TPWD
based on biological function, hydrologic function, riparian conservation areas, high water quality
(including aquatic life and aesthetic value), and threatened or endangered species. TPWD used
scientific literature, existing data, and TPWD expertise to identify 228 segments meeting at least
one of the criteria listed above.
Stream or river segments are considered significant using five criteria: 1) biological
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function, where segments display a high level of biodiversity, age, and uniqueness; 2) hydrologic
function, where segments perform valuable functions related to water quality, flood attenuation,
flow stabilization, or ground water recharge; 3) riparian conservation areas, which includes state
and Federal refuges, wildlife management areas, preserves, parks, and mitigation areas; 4) high
water quality/exceptional aquatic life/high aesthetic value that represents unique or critical
habitat or exceptional aquatic life; and 5) threatened and endangered species/unique
communities where segments represent the presence of unique, exemplary, or unusually
extensive natural communities.
The ecologically significant stream segment designation is not the same as the
ecologically unique stream segment designation. The former has no legal status, but the later
represents a statutorily defined legal category. The criteria used for both stream definition types
are identical in many respects. The act of officially designating a stream segment as
"ecologically unique" is a combined effort of TPWD, TWDB. and the Texas legislature and does
not protect the segment from physical degradation. It prevents a state agency from obtaining a
fee title or easement that would compromise the ecological value of the designated stream
segment. Designation of a segment recognizes the importance of protecting the ecological
legacy of Texas' rivers and streams.
1.3.3.2 Rarity
The rarity layer was designed to show rarity of species and land cover in Texas. The
rarity layer consists of four sub-layers: (1) vegetation rarity, (2) natural heritage rank, (3)
taxonomic richness, and (4) rare species richness.
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1.3.3.2.1 Vegetation Rarity. The land cover or vegetation rarity measure is derived from the U.
S. Geological Survey (USGS) National Land Cover Dataset (NLCD) and represents rarity of all
natural cover types including water and bare rock. Vegetation rarity is a measure of the
particular land cover types that are considered rare within each ecoregion.
1.3.3.2.2 Natural Heritage Rank. The Global Heritage Ranking System created by The
Conservancy is described as:
Gl. SI. Critically imperiled. Critically imperiled globally (G) (or in the state, .81)
because of extreme rarity or because of some factor(s) making it especially
vulnerable to extinction. Typically, this rank consists of five or fewer
occurrences or very few remaining individuals (< 1,000) or acres (< 2,000) or
linear miles (< 10).
G2. S2. Imperiled. Imperiled globally (or in the state, S>2) because of rarity or
because of some factor(s) making it very vulnerable to extinction or elimination.
Typically, this rank consists of 6-20 occurrences or few remaining individuals
(1,000-3,000) or acres (2,000-10,000) or linear miles (10-50).
G3. S3. Vulnerable. Vulnerable globally (or in the state, S>3) either because they
are very rare and local throughout its range, or found only in a restricted range
(Even if abundant at some locations), or because of other factors making it
vulnerable to extinction or elimination. Typically, this rank consists of 21 to 100
occurrences or between 3,000 to 10,000 individuals.
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G4. S4. Apparently secure. Uncommon globally (or in the state, S4), but not rare
(although it may be rare in parts of its range, particularly on the periphery), and
usually widespread. Apparently not vulnerable in most of its range, but possible
cause for long-term concern. Typically, this rank consists of more than 100
occurrences and more than 10,000 individuals.
G5. S5. Secure. Common globally (or in the state, S>5), widespread, and abundant
(although it may be rare in parts of its range, particularly on the periphery). Not
vulnerable in most of its range. Typically, this rank consists of with considerably
more than 100 occurrences and more than 10,000 individuals.
1.3.3.2.3 Taxonomic Richness. Taxonomic richness, or the number of rare taxa is another
measure of rarity. This sub-layer measures the richness of broad taxonomic groupings; that is,
the locations that have a high degree of rarity in multiple taxa, e.g., birds, mammals, reptiles,
amphibians, etc. The number of rare taxa (taxonomic richness) indicates taxonomic diversity.
1.3.3.2.4 Rare Species Richness. Another measure of rarity is rare species richness, or the
number of rare species per ecoregion. The number of rare species (rare species richness) may
indicate the amount of endemism in an area. Rare species may be keystone/umbrella species
(Launer and Murphy 1994) or very productive communities or typify a particular ecological
community type (Poiani etal. 2001).
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1.3.3.3 Sustainability
The sustainability layer describes the state of the environment in terms of stability; that
is, how resistant to disturbance an area is, and how capable is the area in returning to its pre-
disturbance state, that is, resilience (Begon et al. 1986). For the purposes of this report,
sustainable areas are those that can maintain themselves into the future without human
management.
Stability has two components: resistance and resilience. Resistance is defined as an
ecological community's ability to withstand disturbance (Begon et al. 1986). whereas resilience
is the ability of an ecological community to recover from a disturbance (Begon etal. 1986).
Highly sustainable ecosystems are able to resist disturbance, but once disturbed can return to the
pre-disturbance state within a short time period (resilience) (Begon et al. 1986). The
sustainability layer consists of eleven measures that can be loosely grouped into fragmentors: (1)
contiguous land cover type, (2) regularity of ecosystem boundary, (3) appropriateness of land
cover, (4) waterway obstruction, and (5) road density and stressors: (1) airport noise, (2)
Superfund National Priority List (NPL) and state Superfund Sites, (3) water quality, (4) air
quality,(5) Resource Conservation and Recovery Act (RCRA) Treatment-Storage-Disposal sites
(TSD), corrective action and state Voluntary Cleanup Program (VCP) Sites, and (6)
urban/agricultural disturbance.
1.3.3.3.1 Contiguous Land Cover Type. Contiguous land cover is based on the principle that
larger areas having similar ecosystem types have greater sustainability. Contiguous area of
undeveloped land supports connectivity, the opposite of the isolating effects of fragmentation
(Gustafson and Gardner 1996). Larger habitat areas have less edge than smaller habitat areas
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and therefore, can preserve biodiversity (Lee etal. 2001). Larger areas of contiguous habitat can
support large animals or widely-dispersing animals such as carnivores and large ungulates. As
these large areas are fragmented, either through direct habitat loss or through insularization, the
remaining habitat may not maintain viable population of these organisms (Tigas et al. 2002).
Fragmentation of habitats comprises two ecological effects: 1) loss of habitat, and 2)
increased insularization (or isolation) of the remaining habitat (Noss and Csuti 1994). It is a
spatial phenomenon that affects landscape continuity (Robinson et al. 1992) and poses some of
the most significant challenges to ecologists. It is a major threat to landscape continuity and can
disrupt temporal and spatial habitat use by animals (Tigas et al. 2002). The effects of
fragmentation have been demonstrated for a variety of taxa: mammals (Brown 1986. Foster and
Gaines 1991. Chiarello 1999. Lindenmaver et al. 1999): birds (Askinsetal. 1987. Opdam 1991.
Walters et al. 1999): reptiles and amphibians (Johnson 1986. Vos and Stempel 1995): and insects
(Johnson 1986. Thomas and Harrison 1992. Wahlberg et al. 1996).
1.3.3.3.2 Regularity of Ecosystem Boundary. For all land cover types except open water,
conventional ecological wisdom suggests that the smaller the perimeter for a given area, the
larger the core interior habitat. It is based on the principle that the least amount of boundary
results in the lowest amount of "edge effect" thereby yielding the least disturbance and greatest
sustainability of the ecosystem. The reverse is also true; areas with larger perimeters compared
to their areas, will have a greater amount of "edge" habitat and less "interior" or core area. The
more complex the edge, the more opportunities for negative influences to affect the location.
The more negative influences, the less sustainable the location. Habitat edges differ from the
interior in their ecological processes (Donovan et al. 1997) and in physical impacts, such as
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changes in vegetation density, size, shape, matrix habitat, and fragment aggregation. Small
patches may have properties similar to the edge throughout.
The measure of regularity of ecoregion boundary reflects the perimeter to area ratios
(PAR) of areas of particular land cover types. Ecological theory suggests that perfectly circular
or square habitat areas will have higher diversity and/or species abundance compared to linear
habitat areas (Game 1980). However, small narrow areas may provide erosion control to
riparian areas (H. John Heinz III Center for Science. Economics and the Environment 2002).
Habitat edges differ from the interior in their ecological processes (Donovan et al. 1997)
including physical impacts, such as changes in vegetation density, size, shape, and matrix habitat
(Lidicker 1999). Biological impacts to species (Yahner 1988) are well documented. Edges are
transition zones where generalist species thrive. Conventional ecological wisdom concerning
"edge" demonstrate that invasive or opportunistic species prefer the types of habitat associated
with the "edge," or the boundary between two habitat types (H. John Heinz III Center for
Science. Economics and the Environment 2002). As one moves away from the edge there is a
change in species composition (Lee etal. 2001) which can be associated with abiotic factors,
such as temperature, humidity, and vegetation structure flVIcCollin 1998). Unique or rare species
typically use "interior" habitat or may need a large amount of habitat as a home range.
There are many examples concerning edge-interior species. For example, cowbirds and
other parasitic birds prefer the habitat on the agriculture-forest boundary and prey on birds, such
as the black-capped vireo or golden-cheeked warbler, that need a certain amount of habitat away
from this boundary, or interior habitat. Many birds, including warblers and red-cockaded
woodpeckers require forest interior habitat. Large-bodied animals, such as bears and mountain
lions, may need extended habitat areas in which to forage and mate, without the intrusion of
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urban or agricultural activities (Noss and Csuti 1994). Forest areas adjacent to non forest areas
may by more affected by abiotic elements (e.g., wind, heat) and consequently open to invasion
by exotic species (H. John Heinz III Center for Science. Economics and the Environment 2002).
It is widely accepted that the nature of patch edge in aquatic and terrestrial systems
differs greatly due to high differences in the land cover types (water vs land) and differences in
the nature of communities of the interface zones. A more convoluted water/land edge allows for
a greater amount of habitat suitable for the species and communities that live (and often can only
exist) in these interface zones. At the most general level, this land/water edge differs from the
edge between two (or more) terrestrial land cover types because of the difference in the cover
type media (i.e. water vs. land). There is less transfer in species, materials and energy between
these two patch types (i.e., there is less invasion possible either from water to land or vice versa,
and thus less deleterious "edge effect." The term "edge effect" is not widely used in the literature
for water/land boundaries compared to the description of dynamics between terrestrial land
cover patches.
As habitat areas become more fragmented and insularized, the edge habitat tends to
increase and the interior habitat tends to decrease; therefore, impacting the sustainability of rare
or unique species. Because of internal modifications and the lack of intact core areas, small
patches may have properties similar to the edge. A preference for the edge results in a negative
response to habitat area because large habitat areas have smaller PARs than small habitat areas
(Cappuccino and Root 1992). Studies describing habitat "shape" are related to edge effects
through the PAR (Collinge 1996. 1998. Collinge and Forman 1998). In addition, island
biogeographic theory (MacArthur and Wilson 1967) has been used to generate the following
"optimum" characteristics for land and species conservation: large circular, undivided sites (or
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"reserves"), or if the site is divided, then connectivity by corridors (Wilson and Willis 1975.
Diamond and May 1976. Burel 1989) based on these shape and "edge effect" theories.
1.3.3.3.3 Appropriateness of Land Cover. Appropriateness of land cover describes the predicted
natural vegetation under no human influence (Kuchler 1964) and compares it to the current
vegetation cover. The rationale for including this measure in the sustainability layer is that if
pre-settlement and current vegetation types are similar then the seed bank is intact and therefore
the area can recover from a disturbance more quickly (resilience).
1.3.3.3.4 Waterway Obstruction. The waterway obstruction sub-layer is based on the principle
that dams and corresponding reservoirs are interruptions to the continuity of waterways.
Waterway obstruction is a surrogate for fragmentation to water bodies. Dams disturb the natural
flow regime of a river, turning it into a reservoir and non-flowing system. The river
environment, both aquatic and riparian, is fragmented and insularized, thus creating disturbances
for the fish, aquatic organisms and plant communities associated with this habitat.
1.3.3.3.5 Road Density. The road density sub-layer is based on the principle that roads fragment
the landscape (Abbitt et al. 2000). In general, more roads and larger roads (multilane highways,
for example) occur near the population centers and also serve to connect them. The higher the
density of roads, the more fragmentation and disturbance occurs to natural communities (Abbitt
et al. 2000).
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1.3.3.3.6 Airport Noise. The airport noise sub-layer is based on the principle that noise around
airports stresses surrounding habitats thereby lowering the quality of wildlife habitat. Airport
noise is a disturbance to natural communities based upon the noise level from airplanes and
associated activities, maintenance on the runways themselves, and because they serve as a
catalyst for development surrounding the airport. Airports with larger runways typically have
wider areas of disturbance.
Aircraft noise is known to impact wildlife patterns especially those of birds (e.g., feeding,
resting and nesting) and to increase predation on amphibians has been observed. According to
the Federal Aviation Administration (FAA), the noise generated by an aircraft is generally
determined by the thrust powering the aircraft; the amount of thrust an aircraft needs is
proportional to the weight of the plane. That is, the heavier the aircraft, the more thrust it needs
and the more noise is produced. Runway length only defines the heaviest aircraft (total weight)
that can land and take off. While newer aircraft have shorter runway length take off
requirements and reduced noise, many of the older aircraft (e.g., 747 and Lear 25) with high
noise potential remain in service. The buffer distance around airports was used as an indication
of disturbance due to noise. To estimate the distance, the noise disturbance was assumed to be
proportional to the size of the aircraft, and that was proportional to the runway length.
1.3.3.3.7 Superfund National Priority List (NPL) and State Superfund Sites. These are sites
where hazardous substances have been released and are, by definition, disturbances or stressors
on the natural environment. While efforts are made to minimize the impacts of these sites and to
clean up or contain contaminants to acceptable risk level, the release of toxic chemicals may
permanently alter natural conditions. These areas and natural areas adjacent to them are less
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likely to be self sustaining and more likely to require human management for their continued
existence. Once clean up efforts have been completed, further development may be restricted or
prohibited at portions of those sites where waste has been left in place in order to prevent
disturbance of containment areas and subsequent human exposure. For example, future highway
or other construction activities at some sites may need to be avoided. However, with proper
engineering, many such sites can and have been put to productive use. As a consequence,
unique opportunities for low impact restoration of natural or near-natural habitat areas may be
available.
1.3.3.3.8 Water Quality. Water quality or the lack of water quality (defined by Clean Water Act
(CWA) Section 303(d), as not meeting designated uses) is another stressor on the natural
environment. This sub-layer in no way intends to abrogate any obligations or duties assigned by
law to TERS participating agencies.
1.3.3.3.9 Air Quality. Air quality can impact ecological communities due to outfall of chemicals
or particulates that become incorporated in the soil of food chain. Poor air quality may be due to
mobile sources such as the amount of cars or industrial activities, such as petroleum refining.
This sub-layer in no way intends to abrogate any obligations or duties assigned by law to TERS
participating agencies.
High concentrations of ozone can have negative effects on flora and fauna (H. John
Heinz III Center for Science. Economics and the Environment 2002). Ozone can affect water
movement, cycling of mineral nutrients, and habitats for various animal and plant species (EPA
2002). Pollutants such as lead, mercury, and others can be transported and deposited in water or
32
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soil where they may be incorporated into the food chain. Nitrogen and sulphur can acidify some
water bodies, making them uninhabitable for aquatic species (EPA 2002). Acid deposition can
leach nutrients from the soil, consequently affecting plant growth and soil fauna, and enhance
the movement of potentially toxic heavy metals, such as aluminum. Deposition of nitrogen can
cause eutrophic conditions such as algal blooms and decreased oxygen levels, which in turn may
result in fish kills.
1.3.3.3.10 RCRA TSD. Corrective Action and State VCP Sites. These sites are typically smaller
than Superfund sites. RCRA TSD sites are active facilities where hazardous wastes are managed
on site. RCRA corrective action sites are active TSD facilities which have had releases of
hazardous substances and are, by definition, disturbances or stressors on the natural
environment. VCP sites are inactive facilities contaminated by various pollutants which
typically do not qualify for the state or federal Superfund programs and where a third party
wishes to conduct a cleanup in order to redevelop the site. While efforts are made to minimize
the impacts of these sites and to clean up or contain contaminants to acceptable risk level, the
release of toxic chemicals may permanently alter natural conditions. These areas and natural
areas adjacent to them are less likely to be self sustaining and may require human management
for their continued existence. Once clean up efforts have been completed, further development
may be restricted or prohibited at portions of those sites where waste has been left in place in
order to prevent disturbance of containment areas and subsequent human exposure. For
example, future highway or other construction activities at some sites may need to be avoided.
However, with proper engineering, many such sites can and have been put to productive use. As
a consequence, unique opportunities for low impact restoration of natural or near-natural habitat
33
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areas may be available.
1.3.3.3.11 Urban/Agriculture Disturbance. This sub-layer is based on the principle that activities
in urban and agricultural areas generate disturbances (stressors) to surrounding areas. Stressors
such as pesticides, fertilizers, and noise are included.
The urban/agricultural disturbance sub-layer is a surrogate for general population
disturbance. These "developed" land cover types are not considered in the calculations in the
diversity and rarity layers, but are appropriate in this sustainability sub-layer. The sustainability
of an ecological community can be impacted by the amount of human activity, such as those
related to agriculture (e.g., pesticide use, nutrient runoff, erosion, etc.) and population (e.g.,
urban activities including roads, cars, urban sprawl, solid waste, Polycyclic Aromatic
Hydrocarbon (PAH) runoff, general environmental contamination, etc.) (White et al. 1996. H.
John Heinz III Center for Science. Economics and the Environment 2002. Tigas et al. 2002).
Urban uses and agriculture also fragment the community and change natural landscape from
desired vegetation types (e.g., wetland, forest, etc.) to undesirable vegetation types (e.g.,
agricultural monocultures, invasive or opportunistic species) (White et al. 1996. Tigas et al.
2002).
1.3.4 TEAP Development
EPA reviewed over twenty applicable studies and protocols throughout the U.S. (Critical
Ecosystems Workshop 2002). TERS participating agency representatives were invited to
identify studies and methodologies that could be helpful in addressing objectives and to decide
on an appropriate protocol. Reviews resulted in the selection of three protocols for further
34
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adaptation and development: (1) processes and information developed in the TPWD Land and
Water Resources Conservation and Recreation Plan (Texas Parks and Wildlife Department
2002). (2) information generated by The Nature Conservancy of Texas Ecoregional Planning
Process (Groves et al. 2000) and (3) EPA Region 5 Critical Ecosystems Assessment Model
(CrEAM) (Mvsz et al. 2000. White et al. 2003).
1.3.4.1 TPWD Conservation Planning
TPWD has drafted a strategic plan for ecological and recreational resources for both land
and water (Texas Parks and Wildlife Department 2002). TPWD performed an ecoregion priority
analysis, using three main criteria: conserved status, primary level of threat, and biological value.
Conserved status is determined by the percentage of publicly owned land, land owned by non-
governmental conservation groups, large local conserved parkland, and the percentage of the
ecoregion operated under TPWD management plans. Primary level of threat is determined by
comparing the percentage of land converted to urban or agricultural use, fragmentation of
agricultural lands and population growth projections. Biological value is determined by total
vertebrate species richness, vascular plant species richness or actual number of species occurring
in each ecoregion. Over twenty-two categories of data were collected and mapped. Results by
ecoregion are summarized in Table 1.
1.3.4.2 The Nature Conservancy Ecoregional Planning Process
The Conservancy's Ecoregional Planning Process applies a planning and validation
process that includes GIS-based analysis, field investigations, and ecological expertise as to
endangered community types (Poiani etal. 1998. Groves et al. 2000. Poiani etal. 2001). The
35
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Table 1. TPWD planning results. Priority ecoregions for conservation efforts.
Ecoregion
Blackland
Prairie
Gulf Coast
Prairies &
Marshes
South Texas
Plains
Cross
Timbers &
Prairies
Edwards
Plateau
High Plains
Piney Woods
Post Oak
Savannah
Rolling
Plains
Trans Pecos
Priority
High
High
High
Medium
Medium
Medium
Medium
Low
Low
Low
Conserved
Status
Medium
High
High
Low
Medium
Low
Medium
Medium
Low
Highest
Threats
Severely
altered
Most
threatened
High (Lower
Rio Grande)
Medium
Low
Medium
High
Low
Medium
Lowest
Rare Plants Rare
Animals
Lowest Drastic
decline
High Many rare
birds in need
of attention
High Rich bird &
butterfly
faunas and
endangered
cats
Low 2 T&E birds
Highest Important for
herpetological
and
invertebrate
species
Low Numerous
birds and
other species
of concern
Low Highly
diverse
Low Several
species of
concern
One 2 Fed listed
1 state listed
Rarest & Highest
most unique percent of
vertebrate
species of
concern
36
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Conservancy uses four criteria to identify and select areas of biodiversity significance:
occurrence of conservation elements, functionality of those elements, representativeness, and
complimentarity. Conservation elements are those species, natural communities, and ecological
systems that are chosen as the focus for conservation within an ecoregion. The Conservancy has
completed this process, with multiscale mapping of priority ecological areas for Gulf Coast
Prairies and Marshes, West Gulf Coastal Plain, Edwards Plateau, Chihuahuan Desert, Upper
West Gulf Coastal Plain, and the Southern Shortgrass Prairie in Texas. The Cross Timbers and
Southern Tallgrass Prairie and Tamaulipan Thornscrub were scheduled to be completed by June
2003.
The Conservancy process involved field verification of ecological type and because The
Conservancy has not completed its process statewide, The Conservancy data and portfolio
conservation areas are to be used in the preliminary accuracy assessment of TEAP results.
1.3.4.3 EPA Region 5 CrEAM
The EPA Region 5 CrEAM (White et al. 2003) model incorporated three key criteria
based on established ecological theory: 1) diversity, 2) rarity, and 3) sustainability. Twenty
geographically referenced data sets were used to develop indicators for these three criteria. All
data sets were pre-existing or derived from pre-existing data sets. Because of the differences in
data sets, the CrEAM used 25 acres as its smallest unit of measure. Since TEAP modifies the
CrEAM. further details are located in the methods section.
The CrEAM fits within the EPA Science Advisory Board (SAB) ecological framework.
In 2002, the EPA Science Advisory Board (SAB) Ecological Processes and Effects Committee
released a draft framework for assessing and reporting on ecological condition. The purpose of
37
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which was to guide practitioners on designing systems to assess and report ecological conditions.
The framework also helps investigators to organize and decide what features to measure for a
picture of ecological 'health.' Program goals and objectives are used to determine what essential
ecological attributes will be used. There are six broad categories and several subcategories
under each: landscape condition, biotic condition, chemical and physical characteristics,
ecological processes, hydrology/geomorphology, and natural disturbance regimes. The set of six
attributes can be used to determine ecological indicators, or characteristics of ecological systems,
and specific measures and monitoring data used to determine the indicator, or endpoint. It is a
hierarchical structure where measures can be aggregated into indicators and indicators can be
aggregated into attributes. The six attributes are independent of program goals and objectives,
but serve as a stimulus for practitioners to decide what attributes and subcategories are essential
to a project.
Not every attribute category or subcategory is appropriate in every situation; a user must
select those attributes from the SAB framework that provide the best measure and analysis of the
project objectives. Table 2 shows the SAB ecological attribute categories, subcategories,
suggested measure, and corresponding TEAP criterion. The SAB also suggests that the
framework aids in designing the assessment and subsequent report in that it should
"transparently record the decision tree and professional judgements used to develop it." The
TEAP follows this framework since the measures are aggregated into four broad categories
which follow the SAB framework of aggregating measures and indicators; therefore, both single
'media' and aggregate effects (ecological, socioeconomic, etc.) can be considered.
The TEAP allows users to analyze ecological condition, project consequences, and
suggest mitigation within watersheds or ecoregions. The TEAP also adheres to the SAB
38
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framework by being 1) 'multimedia'; 2) interagency (a repository for coordinating other
agencies' data); and 3) understandable to non-scientists by using an intuitive 0 to 100 decision
structure.
The SAB also suggests that reference conditions be defined so that ecological indicators
can be compared and later normalized for aggregation. This concept is imbedded within TEAP
by using a 0 to 100 ranking structure which serves to normalize disparate criteria values.
Table 2. Relationship of the EPA SAB framework ecological attributes to EPA Region 5
CrEAM and TEAP.
ECOLOGICAL PROCESSES
Category
Energy flow
Material flow
Subcategory
primary production
net ecosystem
production
growth efficiency
organic C cycling
N & P cycling
other nutrient
cycling
SAB example
measure
tree growth
CO2flux
carbon transfer
organic matter
quality
N-fixation capacity
input/output budgets
TEAP criterion
NONE
NONE
NONE
NONE
NONE
NONE
LANDSCAPE CONDITION
Extent of habitat
types
Landscape condition
perimeter-area ratio
number of habitat
types
39
regularity of ecosystem
boundary
contiguous size of
undeveloped areas
land cover rarity
-------
Category
Subcategory
SAB example
measure
TEAP criterion
Landscape pattern
contagion
land cover diversity
significant stream
segments
contiguous land cover
appropriateness of land
cover
land cover suitability
urban & agricultural
disturbance
road density
NATURAL DISTURBANCE REGIMES
Ecosystems &
communities
frequency
intensity
extent
duration
BIOTIC
community extent
community
composition
recurrence interval
spatial extent
length of event
CONDITION
extent of
successional state
presence of focal
species
NONE
NONE
NONE
NONE
NONE
number of rare taxa
trophic structure
community
dynamics
feeding guilds
predation rate
number of rare species
species rarity using G/S
rankings
NONE
NONE
40
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Category
Subcategory
SAB example
measure
TEAP criterion
Species &
populations
Organism condition
physical structure
population size
genetic diversity
population
structure
population
dynamics
habitat suitability
physiological
status
symptoms of
disease
signs of disease
tree canopy height
density
degree of
heterozygosity
age structure
dispersal rates
focal species
requirements
hormone levels
tumors, lesions
tissue burden of
contaminants
NONE
NONE
NONE
NONE
NONE
Combination of GIS
layers
NONE
NONE
TRI weighted air/water
releases
CHEMICAL AND PHYSICAL CHARACTERISTICS
Nutrient
concentrations
Trace inorganic &
organic chemicals
Nitrogen
Phosphorus
other nutrients
metals
concentration of N water quality
concentration of total water quality
P
concentration of Ca, water quality
K,Si
Cu, Zn in sediment NONE
trace elements Se in water and soil NONE
organic compounds methyl-Hg NPL (Superfund) Sites
RCRA corrective action
sites
41
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Category
Chemical properties
Physical parameters
Subcategory
PH
dissolved O
salinity
organic matter
other
soil/sediment
SAB example
measure
pH in water & soil
DO in streams
conductivity
soil organic matter
buffering capacity
temperature, texture
TEAP criterion
NONE
water quality
NONE
NONE
NONE
soil permeability,
air/water
concentration of
particulates
air quality
change in elevation
airport noise
temperature &
precipitation maxima
HYDROLOGY & GEOMORPHOLOGY
Surface &
groundwater flows
Dynamic structural
characteristics
pattern of surface
flow
hydrodynamics
pattern of groundwater
flows
spatial salinity
patterns
water storage
channel morphology
complexity
dist. of connected
floodplain
water level
fluctuations
water movement
watershed obstructions
waterway
impoundments
NONE
depth to groundwater NONE
surface salinity NONE
gradients
aquifer capacity NONE
length of natural NONE
shoreline
2yr or 1 Oyr floods NONE
42
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Category
Subcategory
SAB example
measure
TEAP criterion
Sediment & material
transport
aquatic physical
habitat
sediment
movement
particle size
distribution
pool-riffle ratio
NONE
sediment deposition NONE
distribution of grain NONE
size
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2. 0 METHODS
2.1 Base Unit Selection
Technical experts from TERS agencies discussed the relative merits of using ecoregions
or watersheds as the base unit for the assessment. It is generally agreed that both watersheds and
ecoregions provide "essential geographic frameworks necessary to describe, diagnose, and
eventually, predict landscape influences on water resources" (Harrison et al. 2000). The TERS
Steering Committee concluded that ecoregions have the following distinct advantages over
watersheds for ecosystem management:
An ecoregion approach provides a comprehensive review of an area's
functionality in relationship to terrestrial habitat, aquatic habitat, and the species
and communities they supported. Some species and communities depend upon a
single large patch or several different kinds of habitat that span more than one
watershed.
Texas has over 200 watersheds. A watershed-based assessment would be time
and resource intensive. Therefore, using watershed-based assessment would not
be expedient enough to meet the initial needs identified by the TERS executives.
Large watersheds, particularly basins, do not necessarily correspond to areas that
contain a similarity in the mosaic of geographic characteristics which include,
physiography, soils, vegetation, geology, climate, that influence the physical,
chemical or biological nature of water bodies (Omernik 1995. Omernik and
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Bailey 1997). However, the quantity and quality of water tends to be similar
within ecoregions (Griffith et al. 1999).
Land cover and other spatial data are readily available by ecoregion to summarize
and map numerous landscape features thought to be important to water quality
concerns.
Ecoregions are functional conservation areas that maintain focal species,
communities, and/or systems, and support ecological processes within their
natural ranges of variability (Poiani et al. 1998. Poiani and Richter 1999. Poiani et
al. 2001).
TEAP used ecoregions, developed by Bailey (1985. 1987. 1994. 1996) because of
extensive delineation of representative ecoregions and sub-regions within Texas and the use of
plant community relationships (Bailey 1994) (Figure 1). There are eighteen ecoregions
identified by Bailey in Texas. The characteristics of each are described in Appendix A. Bailey's
ecoregions has broad usage by a number of agencies and organizations, including the USFS.
USGS. FWS. EPA, and The Conservancy.
GIS data, particularly NLCD. used in specific calculations were summarized for each
square kilometer (1km2). Although NLCD has a 30 m2. pixel resolution, performing calculations
for a "1 km2 grid" allowed maintenance of confidentiality of rare species occurrences, as well as
reducing computer computation resources.
The NLCD classification contains twenty-one different land cover categories with a
45
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spatial resolution of 30 m. The NLCD was produced as a cooperative effort between USGS and
EPA to produce a consistent, land cover data layer for the conterminous U.S. using early 1990s
Landsat thematic mapper data purchased by the Multi-resolution Land Characterization (MRLC)
Consortium. The MRLC Consortium is a partnership of federal agencies that produce or use
land cover data. Partners include the USGS. EPA. USFS. and the National Oceanic and
Atmospheric Administration (NO A A).
Several steps are used to process NLCD: 1) an automated process is used to create
clusters of pixels for a given regional area, 2) these clusters are interpreted and labeled with the
help of aerial photographs, 3) in cases where clusters of pixels include multiple land cover types,
models that use data such as elevation or population density, are used to help assign land cover
classes, and 4) lands that are bare and many grassy areas, such as parks and golf courses are not
easily distinguished from other land cover classes, so on-screen verifications are used for
clarification (Vogelmann et al. 1998. 20011
The analysis and interpretation of the satellite imagery was conducted using very large,
sometimes multi-state image mosaics (i.e. up to eighteen Landsat scenes). Using a relatively
small number of aerial photographs for 'ground truth', the thematic interpretations were
necessarily conducted from a spatially-broad perspective.
The accuracy of NLCD and satellite-derived data is related to many factors including the
amount of data available, the detail of the required land cover information, classification
methods, computing power, and time and money (H. John Heinz III Center for Science.
Economics and the Environment 2002). Furthermore, the accuracy assessments are performed
on groupings of contiguous states. Thus, the reliability of the data is greatest at the state or
multi-state level. Assessments of the NLCD for the eastern U.S. indicate an accuracy of
46
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approximately 80% or higher for general land cover categories (e.g., forest, agriculture,
developed) (H. John Heinz III Center for Science. Economics and the Environment 2002).
2.2 TEAP Sub-layers and Layers
Ultimately, the CrEAM (Mvsz et al. 2000. White et al. 2003) was selected as a base
method. Due to differences between Region 5, the Midwest U. S., and Texas, subsequent
modifications were made (Table 3).
Data were provided by EPA. TPWD. TCEQ (Table 4) and The Conservancy (for the
spatial accuracy assessment). Data were processed and analyzed by EPA Region 6, TPWD. and
The Conservancy (spatial accuracy assessment). Several processing steps were needed to
convert the data or coverages to the same scale. General descriptions of the layers and sub-
layers can be found in the Introduction.
2.2.1 Diversity Layer
The overall diversity layer was calculated for each ecoregion by taking the mean of the
four diversity sub-layers and reseating on a 0-100 scale. The values of the 30 m pixels that made
up each 1 km2 grid cell were averaged to determine the Diversity Index score for each cell.
2.2.1.1 Appropriateness of Land Cover
TEAP reclassified the Potential Natural Vegetation (PNV) 2000 (Kuchler 1964) grid to
the NLCD classification (Table 5). Reservoirs were also reclassified and grouped according to
ecoregion because of their anthropogenic nature. The current NLCD was compared to the
modified PNV 2000 data and values that were the same received a score of 10,000, representing
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Table 3. Summary of TEAP layers.
Criterion
Diversity
Indicator
Shannon land
cover diversity
index
Description
1 . Shannon Diversity
Index
2. Considers both
Data
Source
NLCD.
Bailey's
ecoregions
Analysis
Unit
ecoregion
Analysis
Resolution
1km
Pixel
Scoring
continuum,
exponential
distribution
Land cover
appropriate-
ness
Contiguous
size of
undeveloped
land
Ecologically
significant
stream
segments
Temperature
and
precipitation
maxima
2.
richness (# of different
specific land cover
types) and evenness
(dispersion of cover
types)
Undeveloped land
cover types only
Relative land cover
diversity within
ecoregions
Evaluation of land
cover type currently
present (c. 1993)
relative to potential
dominant vegetation
native to the area as an
appropriateness factor
of measured diversity
Comparison of NLCD
land cover and PNV
Selection of largest
contiguous non-
developed areas based
on principle that larger
non-developed areas
favor diversity
All undeveloped cover
types that are adjacent
form one polygon
1. Relates health of
waterways relative to
pristine conditions of
water quality, habitat
quality, and occurrence
of health indicator
aquatic species
1. Based on assumption
that higher
temperatures and
greater precipitation
favors diversity
NLCD.
PNV
Texas
30m
0/1
NLCD.
Bailey's
ecoregions
ecoregion 1 km
continuum,
exponential
distribution
TPWD
Texas
stream
segments
0/1
ecoregion
meteoro-
logical
bands
0/1
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Criterion
Rarity
Sustainability:
Fragmentation
Indicator
Vegetation
rarity
Natural
heritage rank
Rare species
richness
Taxonomic
richness
Contiguous
land cover
type
Description
1. Determination of
which land cover type
is the rarest
1. Gl, G2, G3, SI, S2,
and S3 occurrences
1 . The number of species
rated as Gl-3
2. The number of
observations
associated with each
species
1 . The number of species
rated as Gl-3
2. The number of broad
taxonomic groups
represented
1 . Selection of largest
contiguous areas by
specific land cover type
Data
Source
NLCD
BCD
BCD
BCD
NLCD.
Bailey
ecoregions
Analysis
Unit
ecoregion
7.5 minute
quadrangle
7.5 minute
quadrangle
7.5 minute
quadrangle
ecoregion
Analysis
Resolution
30m
point
observations
point
observations
point
observations
30m
Pixel
Scoring
continuum,
log
distribution
continuum,
exponential
distribution
continuum,
exponential
distribution
continuum,
exponential
distribution
continuum,
exponential
distribution
Appropriate-
ness of land
cover
2. Based on the principle
that larger areas having
similar ecosystem
types have greater
Sustainability
3. Each undeveloped land
cover type is a separate
polygon
4. Only polygons >10 ha
considered
1. Comparison of NLCD
land cover with PNV
2. Evaluation of land
cover type currently
present (c. 1993)
relative to potential
dominant native
vegetation as an
indicator of resilience
and the likelihood of
Sustainability (seed
bank) of the
corresponding
ecosystems
NLCD.
PNV
Texas
30m
0/1
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Criterion Indicator Description Data Analysis Analysis Pixel
Source Unit Resolution Scoring
Road density 1.
2.
Roads fragment the TIGER 1km cells 1km
landscape
Road density index
continuum,
exponential
distribution
Regularity of
ecosystem
boundaries
Waterway
obstruction
Waterway
impoundment
applied to TIGER road
data set considers the
total road lengths of
different road
classifications,
classification of 1 km
cells into road density
ranges
Selection of contiguous
areas possessing the
smoothest or least
irregular boundaries
(i.e., lowest PAR by
land cover)
Based on the principle
that the least amount of
boundary results in the
lowest amount of "edge
effect" thereby yielding
the least disturbance or
greatest sustainability
of the interior
ecosystems
Only polygons >10 ha
considered
Dam density per
watershed (normalized
by stream miles)
Dams and the
corresponding
reservoirs are
interruptions
(fragmentation) to the
continuities of
waterways
Selection of reservoirs
for downgrading
Intersection of NLCD
open water class and
STORET dam
locations
NLCD.
Bailey's
ecoregions
ecoregion 30 m
continuum,
exponential
distribution
8-digit
HUC
HUC
continuum,
log
distribution
STORET Region 5 30 m
0/-1
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Criterion Indicator
Sustainability: Airport noise
Stressors
NPL sites
(Superfund) &
state
Superfund
sites
RCRA TSD.
corrective
action, and
state VCP
sites
* Air quality
Description
1 . The zone of
disturbance
surrounding airports
are directly related to
the sizes of the
airplanes using them.
2. Airplane sizes are
directly related to
airport runway lengths.
3 . The extent of the zone
of disturbance is
directly related to the
runway length.
1. Un-owned sites where
hazardous waste was
released to the
environment and which
were in the formal
clean-up process
1 . Owned sites where
hazardous waste was
released to the
environment and which
were in the formal
clean-up process
1. Nonattainment and
state near
nonattainment areas
Data Analysis
Source Unit
Bureau of airport
Transportat
ion
Statistics
runway
length
CERCLIS Texas
data,
TCEO
RCRIS Texas
data,
TCEO
EPA green county
book,
TCEQ
Analysis Pixel
Resolution Scoring
site or runway
runway w/buffer
length w/
buffer
site w/buffer 0/1
facility 0/1
w/buffer
county 0/0.5/1
Urban/
agricultural
disturbance
Activities in urban &
agricultural areas
generate disturbances
to surrounding areas.
Takes into account
stressors such as
pesticides, fertilizers,
and noise
NLCD
Texas
30m
0/1
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Criterion
Indicator
Water quality
Description
1 . Ambient levels of total
suspended solids,
dissolved oxygen, and
Data
Source
TCEQ
CWA
303(d) list
Analysis
Unit
Texas
Analysis
Resolution
stream
Pixel
Scoring
0/1
ammonia based on
modeling of 1990-1994
NPDES permitted
discharges levels
Status of water quality
use support, including
waters identified as
impaired, with water
quality concerns, or
fully meeting uses
Only use support
pertaining to aquatic
life is included
(includes depressed
dissolved oxygen, pH
extremes, ambient
toxicity, elevated heavy
metals, and nutrient or
sediment quality
concerns)
*addition/modification to CrEAM
**deletion from CrEAM
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Table 4. GIS data layers used for the TEAP.
Criterion
Database
Description
Scale
Date Agency
Diversity
NLCD
PNV
Bailey's
ecoregions
section map
ecological
stream
segments of
concern
Sustainability NLCD
Bailey's
ecoregions
reservoirs/dams
STORE!
TIGER road
data
CERCLIS
RCRIS
land use/land
cover interpreted
from satellite
imagery
PNV is the climax
vegetation that
will occupy a site
without
disturbance or
climatic change.
It is an expression
of environmental
factors such as
topography, soils,
and climate across
an area.
ecosystem
geography based
on plant
community
relationships
ecologically
significant
river/stream
segments
waterway
impoundments
NPL sites
RCRA corrective
action sites
30m
PNV map was
digitized for the
coterminous US
then adjusted to
match terrain
using a 500 m
DEM. 4th code
HUC. and Bailey
ecological
subregions
1:7,500,000
1990- USGS
1992
1964 USFS
(v.
2000)
1994 USFS
1:200,000
2000- TPWD
2001
EPA
Census
EPA
EPA
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Criterion Database
TMDLs
14-digit & 8-
digitHUC
TRI
Description Scale
CWA 303(d)
listed impaired
waterbodies
watersheds 1:1,000,000
reported facility
Date
1993-
1998
2002
Agency
TCEO
USGS,
NRCS
EPA
Rarity
Other
BCD
natural heritage
conservation
planning areas
air emissions
T&E elemental
occurrences
G/S species
rankings
aquatic and
terrestrial areas
capturing a range
of rare and
representative
native plants,
animals and
natural
communities
7.5' quadrangle
and county
7.5' quadrangle
and county
1994 TPWD
1994 TPWD
TNC
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Table 5. Kuchler (1964) PNV classifications and corresponding NLCD land cover types.
PNV
Class. No. NLCD
Class. No.
Cross timbers 40
Oak-hickory 45
Pine-Douglas fir 3
Pine forest 1
Juniper-pinyon 22
Chaparral 26
Oak-hickory-pine 55
Southern mixed forest 56
Southwest shrub steppe 27
Desert shrub 28
Shinnery 29
Texas savannah 35
Plains grassland 32
Prairie 33
Desert grassland 34
Open water 11
Perennial ice/snow 12
Low intensity residential 21
High intensity residential 22
Commercial/Industrial/Transportation 23
Bare rock/sand/clay 31
Quarries/strip mines/gravel pits 32
Transitional 33
Deciduous forest 41
Deciduous forest 41
Evergreen forest 42
Evergreen forest 42
Evergreen forest 42
Mixed forest 43
Mixed forest 43
Mixed forest 43
Shrubland 51
Shrubland 51
Shrubland 51
Shrubland 51
Orchards/vineyards/other 61
Grasslands/Herbaceous 71
Grasslands/Herbaceous 71
Grasslands/Herbaceous 71
Pasture/Hay 81
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PNV
Southern floodplain
Wet grassland
Reservoirs
Class. No. NLCD
Row crops
Small grains
Fallow
Urban/recreational grasses
61 Woody wetlands
36 Emergent herbaceous wetlands
63 Various; dependent on ecoregion
Class. No.
82
83
84
85
91
92
no change from pre-settlement to modern times and those that were not the same received a
score of zero, indicating disturbance due to human activities. The 0 to 10,000 values, based on
thirty meter pixels, were then converted to a 0 to 250 scale and reclassified the resulting data
onto an 8-bit grid. It was rescaled so that the data could be stored as 8-bit. Eight-bit data avoids
computer memory and buffer overloads during processing and in no way affects the outcome,
since the relative scores within the data set accurately reflect the content of the data. The final
score is an average of all pixels in a 1 km2.
Kuchler's PNV map was refined by USFS to match terrain using a 500 m Digital
Elevation Model (DEM). 4th level Hydrologic Unit Codes (HUC), and Ecological Subregions
(Bailey's Sections). These biophysical data layers were integrated with current vegetation layers
to develop generalized successional pathway diagrams. Expert regional panels refined the PNV
map based on these successional pathways. Summaries of the data were restricted to state or
USFS regional scales.
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2.2.1.2 Contiguous Size of Undeveloped Land
Using NLCD coverage and land cover classes, the data were classified as either
developed or non-developed within each ecoregion. "Non-developed" classes are identified by
the following land cover categories: 1) open water, 2) bare rock/sand/clay, 3) deciduous forest,
4) evergreen forest, 5) mixed forest, 6) shrubland, 7) grasslands/herbaceous, 8) woody wetlands,
and 9) emergent herbaceous wetlands. All other classes are considered "developed."
For this measure in TEAP. adjacent undeveloped land cover types in each ecoregion are
combined into one polygon, e.g., adjacent forest, wetlands, and grasslands are all one polygon.
Thirty meter pixels of each land cover type were scored in each ecoregion. The size of the
contiguous area in each Texas ecoregion was computed as was a linear index based on area using
the following parameters: (1) contiguous areas < 10 hectares (ha) received a score of zero,
indicating small areas of an undeveloped land cover type; and (2) contiguous areas > 100,000 ha.
received a score of 250, indicating large areas of an undeveloped land cover type in each
ecoregion. All other areas were ranked in the index by dividing the total contiguous area by 400.
Reseating was done so that the data could be stored as 8-bit data which avoids computer memory
and buffer overloads during processing. Reseating does not affect the outcome, since the
relative scores within the data set accurately reflect the content of the data.
2.2.1.3 Shannon Land Cover Diversity Index
This calculation applies the Shannon-Weiner diversity index using the NLCD coverage
to the relative land cover diversity within each ecoregion. The Shannon index is an established
method used to measure ecological diversity (richness and evenness) (Begon et al. 1986). It
usually calculates the proportion of individuals, but as used here, land cover types, related to the
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total number of land cover types. Other ecological diversity measures used in landscape
assessment are discussed in Herzog et al. (2001). The Shannon-Wiener equation considers both
richness (the quantity of different categories) and the evenness (the similarity of relative
abundance).
The Shannon land cover diversity index for each ecoregion was calculated using the
Analytical Tools Interface for Landscape Assessments Version 3.0 (ATtlLA) (Harrison et al.
2000). Water land cover classes were removed in the GIS coverage used due to human-made
reservoirs. Calculations were made by summarizing 30 rnf pixels into a one kilometer grid. The
results of the Shannon land cover diversity index calculations using ATtlLA were normalized to
a 1 to 250 scale so that the highest value in an ecoregion is equal to 250 and the lowest value is
equal to one. The 1 to 250 scores were then used to populate the 1 km raster grid.
Reservoirs are considered "developed" due to the managed and many, characteristically
"unnatural" attributes when compared to natural lakes. Differences in shoreline shape, nutrient
balance, water temperature, drainage characteristics, salinity, plus the lack of or reduced
seasonal flow fluctuation (though this may be simulated by controlled dam releases) contribute
to lower biodiversity, and lower "ecological value" of this land cover type as compared to
natural and non managed aquatic ecosystems.
2.2.1.4 Ecologically Significant Stream Segments
For this sub-layer, the initial data was reprojected from the Texas State Mapping System
(TSMS) to TxAlbers map projection and attribute data was added to facilitate overlays with
other coverages. The results were applied to the raster grid and all grid cells containing
significant stream segments received a value of 10,000.
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2.2.2 Rarity Layer
The overall rarity layer was calculated by taking the mean of the four rarity layer sub-
layers and reseating on a 0 to 100 scale. The values of the 30 m pixels that made up each 1 km2
grid cell were averaged to determine the rarity score for each cell. Overall rarity was calculated
by receding rarity ranks using an exponential growth function 0 to 250 to produce a statewide
land cover rarity data set. Data were scaled 0 to 250, due to machine processing of 8-bit data.
Because the input data sets for Texas were large, reseating the data from 1 to 250 (8-bit) allowed
for much faster machine processing without any significant loss of granularity. Exponential
scaling was chosen to give appropriate weight to rarer features. The statewide land cover rarity
data set and the land cover rarity by ecoregion data set were input into an averaging model to
compute the mean value of each grid cell for the combined data sets.
2.2.2.1 Vegetation Rarity
The land cover or vegetation rarity measure is derived from the NLCD and represents
rarity of all natural (undeveloped) cover types including water and bare rock. The following
cover types are represented in this data set: 1) open water, 2) bare rock/sand/clay, 3) deciduous
forest, 4) evergreen forest, 5) mixed forest, 6) shrubland, 7) grasslands/herbaceous, 8) woody
wetlands, and 9) emergent herbaceous wetlands. All developed (non-natural) cover types were
receded as no-data. Because some land cover types may be common at the ecoregion level but
rare statewide (e.g. coastal wetlands), land cover rarity was assessed at both the ecoregional and
statewide level, then combined to produce a final land cover rarity measure. This process avoids
under-evaluation of many important and rare cover types. For example, wetlands are rare
statewide, but may be locally common in an ecoregion. The results of the two analyses
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(ecoregion and state) were combined by averaging the values of the corresponding grid cells to
obtain an "average score" reflecting both the ecoregional and state scales. Pixel counts were
conducted for each of the ecoregions and each cover type was receded to a rarity rank based on
its frequency distribution. Land cover rarity ranks were then receded using an exponential
growth function of 0 to 250 scale. Reseating was done so that the data could be stored as 8-bit.
Eight-bit data avoids computer memory and buffer overloads during processing and in no way
affects the outcome, since the relative scores within the data set accurately reflect the content of
the data. A shape file containing ecoregions was overlain on the NLCD coverage and a
frequency distribution of land cover type by ecoregion was tabulated. The highest number of
occurrences of a land cover type was considered the most common and given a score of one.
The smallest number of occurrences of a land cover type was considered the rarest, and it was
given a score of 10,000. Vegetation rarity was averaged over 30 m pixels in each 1 km2 grid
cell.
2.2.2.2 Natural Heritage Rank
This measure is derived from the TPWD's Biological Conservation Database (TXBCD).
TXBCD. established in 1983, is TPWD's most comprehensive source of information on rare,
threatened, and endangered plants, animals, invertebrates, high quality natural communities, and
other significant features. The TXBCD is continually updated, providing current or additional
information on statewide status and locations of these unique elements of natural diversity.
However, the data are not all-inclusive. There are gaps in coverage and species data due to the
lack of access to land or data, and insufficient staff and resources to collect and process data on
all rare and significant resources.
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The TXBCD was developed by The Conservancy back in the early 1970's and was
continually maintained and updated by The Conservancy until its central science function was
established as the Association for Biodiversity Information (now NatureServe). The data set that
TPWD maintains as TXBCD is operating on an expired license. The official node of the
NatureServe network in Texas is the Texas Conservation Data Center (TxCDC) housed within
The Conservancy. The TxCDC collaborates with and provides data to TPWD. but there is no
data sharing agreement at this time. The TxCDC database (BIOTICS), is a geographically-based
system that contains records on nearly 9,000 species and communities in Texas.
Natural heritage rank for TEAP is derived from TXBCD attributes of global rank, state
rank, federal protection and state protection. Natural heritage rank for TEAP is an absolute rank
based upon natural heritage ranking criteria; which is itself a measure of rarity. Very specific
criteria are used to determine rarity both globally and statewide, which is reflected in the natural
heritage ranking system.
The natural heritage rank sub-layer reflects the combination of the state and global
rankings for rare species in the state. Those that have a combined Gl and £1 rank are the "most
imperiled." Locations that support Gl or £1 species are by definition unique ecological areas.
Any state or federal listed species gets a rank= 1. TEAP ranks of 2-10 were computed by
combining the SRANK and GRANK into a single score, e.g. Gl + S2 = TEAP rank 3 etc.
Because the spatial accuracy of each TXBCD point ranged from 30m to 8km. initial
attempts at producing a polygon data set reflecting the spatial and attribute accuracy of the
TXBCD produced a complex series of "regions" where polygons overlapped. Each of the
thousands of resulting regions had multiple values for the class attribute. Accordingly, a
decision was made to compute rarity by USGS quadrangle (7.5 minute) by intersecting the
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TXBCD points with the USGS quadrangle boundaries. To better reflect the spatial extent of
actual TXBCD data, the resulting USGS quadrangle shapes (attributed for rarity) were then
intersected with the buffers (based on the spatial accuracy attribute of each point) of the TXBCD
points, thus eliminating areas of the quad sheets beyond the actual spatial limits of the buffered
points
After Natural heritage rank was computed, its value was used to populate the "class"
field for TXBCD point shape file. Each class was then selected iteratively and separate shape
files were created for each class. A spatial select of each TXBCD class was then done by USGS
quadrangle boundary using a USGS quadrangle boundary shape file. Each quadrangle was
accordingly attributed with a single class attribute reflecting the highest class rank that occurred
within it. A separate polygon file was then generated from the TXBCD point shape file
corresponding to the documented spatial accuracy of each point using the "precision" field.
Seconds precise points were buffered to 30 m, minutes precise to 1800 m, etc. This file was then
used to clip out the 7.5 minute quadrangle polygons to create a polygon coverage reflecting the
known spatial extent (spatial accuracy of the TXBCD points) attributed with the corresponding
USGS quadrangle's "class" attribute. Finally, the polygons were attributed for class rank using
the process used for the TXBCD point data described above. The resulting attributed polygon
shape file was then merged with the output from the clip process described above to produce a
species rarity shape file.
2.2.2.3 Taxonomic Richness
The taxonomic richness measure, or the number of rare taxa per USGS quadrangle, is
derived from the TXBCD. The TXBCD point data were filtered by the same method used for
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the rarity rank measure. The number of observations of discrete broad taxonomic groups was
based on classifications by The Conservancy (bryophyte, pterodophyte, gymnosperm plant, dicot
plant, monocot plant, lichen, platyhelminthe, uniramian arthropod, insect, chelicerate,
crustacean, mollusk, fish, amphibian, reptile, bird, and mammal). Unique values for the attribute
for taxa were summed for each quad in which an observation occurred. The unique number of
taxa per grid cell was sorted using a max filter to preserve the highest possible number of taxa
per grid cell then receded 0 to 250.
2.2.2.4 Rare Species Richness
The rare species data set suffers from a lack of geographic coverage and up-to-date
inventories for many species, but is the best data set available. The species richness measure, or
the number of rare species per USGS quadrangle, is derived TXBCD. The TXBCD point data
were filtered by the same method used for the rarity rank measure and further processed and
computed similar to the taxonomic richness measure described above.
2.2.3 Sustainabilitv Layer
2.2.3.1 Contiguous Land Cover Type
Sources used for this layer were the NLCD and Bailey's Ecoregion Sections. Only
undeveloped land cover types over 10 ha (100,000 square meters) were scored. The land cover
types that were identified as undeveloped were 1) open water, 2) bare rock/sand/clay, 3)
deciduous forest, 4) evergreen forest, 5) mixed forest, 6) shrubland, 7) grasslands/herbaceous, 8)
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woody wetlands, and 9) emergent herbaceous wetlands. The bare rock/sand/clay class
designation contains features such as natural rock exposures, beaches, and sandbars and does not
include mines and quarries. Using the ArcGIS Spatial Analyst Extension, adjacent cells of the
same land cover type were grouped together and then the total area was calculated for each
region (contiguous cells of the same land cover type). The Iog10 of each area was calculated and
then normalized to a 0 to 100 in each ecoregion by land cover type. The largest area of each
land cover type within each ecoregion received a score of 100. The smallest area of each land
cover type within each ecoregion received a score of one. Other areas were scored exponentially
between 1-100. Developed lands and undeveloped lands under 10 ha received a score of zero.
2.2.3.2 Regularity of Ecosystem Boundary
Sources used for this layer were the NLCD and Bailey's Ecoregions. Only undeveloped
land cover types over 10 ha were scored. The land cover types that were identified as
undeveloped were 1) open water, 2) bare rock/sand/clay, 3) deciduous forest, 4) evergreen forest,
5) mixed forest, 6) shrubland, 7) grasslands/herbaceous, 8) woody wetlands, and 9) emergent
herbaceous wetlands.
The optimum case would be a perfect circle where the PAR approaches or is equal to
one. Therefore, PAR would be (2*pi*r)/(pir2) = 2/r. Since it is preferable to represent PAR as a
relative measure, rather than in absolute units, PAR is represented as [ideal PAR / real PAR].
This ratio is always less than or equal to one. Using the ArcGIS Spatial Analyst Extension,
adjacent cells of the same land cover type were grouped together and the area and perimeter
were then calculated for each region (contiguous cells of the same land cover type). The values
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for each polygon region ranged from 1.0 to 0.0000001. This value was then normalized to a 0 to
100 in each ecoregion by land cover type. With the exception of open water cells, the largest
value of each land cover type within each ecoregion received a score of 100. The smallest value
of each land cover type within each ecoregion received a score of one. Other values were scored
exponentially between 1 to 100. For open water, the smallest value received the score of 100
and the largest value received the score of zero. Developed lands and undeveloped lands under
10 ha received a score of zero. A score of 100 means that the polygon is nearly a circle and a
score of one is the most irregular polygon in the layer. This was done for each land cover type.
For open water, irregular shorelines were deemed as being more ecologically important and
received a score of 100. The open water portion of these reservoirs was scored zero to account
for the reduced ecological value of open water as compared to the shoreline habitat.
2.2.3.3 Appropriateness of Land Cover
Appropriateness of land cover is calculated as described in the diversity section. TEAP
reclassified the PNV 2000 (Kuchler 1964} grid to the NLCD classification (Table 5Y
Reservoirs were also reclassified and grouped according to ecoregion because of their
anthropogenic nature. The current NLCD data was compared to the modified PNV 2000 data
and values that were the same received a score of 10,000 representing no change from pre-
settlement to modern times and those that were not the same received a score of zero, indicating
disturbance due to human activities. The 0 to 10,000 values, based on thirty meter pixels, were
then converted to a 0 to 250 scale and reclassified the resulting data onto an 8-bit grid.
Reseating was done so that the data could be stored as 8-bit. Eight-bit data avoids computer
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memory and buffer overloads during processing and in no way affects the outcome, since the
relative scores within the data set accurately reflect the content of the data. The final score is an
average of all pixels in a 1 km2.
2.2.3.4 Waterway Obstruction
Sources used for this layer were data on dams from TCEQ. the National Hydrography
Dataset (NHD) and 4th level (8-digit) HUCs from the USGS. This is the most refined level of
hydrologic data that covers the entire state and is the best available data for the State of Texas.
For each HUC in the state, the number of dams and the total length in miles of all streams and
rivers was calculated. The number of dams was then divided by the stream miles to calculate
dams per stream mile. This number was then normalized from 1 to 100 for each ecoregion.
Those hydrologic units without dams received a score of 100 and the hydrologic unit in each
ecoregion with the highest number of dams per stream mile received a score of one.
2.2.3.5 Road Density
Sources used for this layer was the 2000 Topological Integrated Geographic
Encoding and Referencing System (TIGERVline files from the U.S. Bureau of the Census. For
each 1 km2 cell the number of road miles by road classification was calculated. The road miles
were then modified by multiplying the road miles with a factor based on the road classification.
The following factors were applied to each road type:
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TIGER Code Classification Factor
AO-A9 Miscellaneous Roads 1
A10-A29 Primary Roads 3
A30-A39 Secondary Roads 2.67
A40-A49 Local & Rural Roads 2
A50-A79 Miscellaneous Roads 1
After multiplying the road length by the road factor above, the totals for each classification were
summed for each 1 km2 cell. The Iog10 was then calculated for each cell. These were then
normalized to 0 to 100. Cells having no roads would indicate no fragmentation and would be the
ideal condition. These cells were given a score of 100. Cells having the highest density of roads
were scored zero. Road density was calculated using the following formula:
(R*F) i-v = L
S = {l-[loglo(L)/5.919]}*100
where R = the total road length of a classification code type within a grid cell
F = the loading factor for a classification code type
i-v = the five classification code types
L = the total loaded road length for a grid cell
S = the inverse loaded road length for a grid cell, i.e., road score
5.919 = Iog10 [road length*F]
A road score of 100 indicates an absence of roads and represents the ideal condition for self-
sustainability.
The factors were derived from Sutherland (1994). In this document, the conclusion is
made that disturbance effects may extend 500 to 600 m from quiet rural roads to 1600 to 1800 m
from busy highways. Therefore, a factor of three presumably exists between the zones of
disturbance generated by the smallest, least used roads and large, interstate highways. Local and
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rural roads are presumed to be intermediate generators of disturbance (thereby receiving a factor
of two), whereas secondary roads, which include U.S. highways and state roads, are presumed to
create disturbance regimes more similar to primary roads than to local and rural roads, thereby
receiving a factor of 2.67. Since a road score of 100, indicates the complete absence of any
roads, it represents ideal road presence for ecological self-sustainability.
2.2.3.6 Airport Noise
All runways were buffered, representing a zone of minimum disturbance around the
airport based on runway size (Sutherland 1994). The buffer distances used were selected
because the size of the zone of disturbance surrounding an airport is proportional to the size of
the aircraft using it. Airplane size is directly related to the length of the runway. Therefore, the
extent of the area of disturbance around an airport is related to runway length. The buffer zone
is proportional to the runway length and each runway was grouped as follows (White et al.
2003V
Airport Category Buffer (m) = Runway Length (m)
very large
large
medium
small
very small
very very small
7500
5300
3100
900
755
610
> 1950
1500-1800
1200-1500
540-1200
183-540
< 183
All areas in the state within the buffer were scored zero and areas outside the buffer were scored
100. This layer was then converted to a grid with a cell size of 1 km2.
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2.2.3.7 Super fund NPL and State Super fund Sites
Sources used for this layer include the NPL sites (in polygon and point format) from EPA
and state Superfund Sites from TCEQ (in point format). For sites where polygon data was
available, the polygon data was used. Otherwise a buffer of 610 m was used as a default
(Sutherland 1994) and applied to the points. All areas in the state within a buffer were scored
zero and areas outside of the buffer were scored 100. This layer was then converted to a grid
with a cell size of 1 km2. These are un-owned sites where hazardous waste was released and
where there was a formal clean up process during fiscal year 2000.
2.2.3.5 Water Quality
This includes waters identified as impaired with water quality concerns or meeting
designated uses in CWA Section 303(d). Only designated use data pertaining to aquatic life is
included (e. g., dissolved oxygen, pH extremes, ambient toxicity, elevated heavy metals, nutrient
or sediment levels in excess of the statewide 85th percentile). The CWA 303(d) year 2000 list is
an assessment of water quality data collected during 1993-1998 by TCEQ. The impaired waters
layer was intersected with the 1 km2 cell grid. Cells with impaired waters were scored zero and
all others cells were given a score of 100.
2.2.3.9 Air Quality
The Air Quality layer characterizes areas with poor air quality. The source for this layer
is ozone nonattainment from EPA's Office of Air Quality Planning and Standards (OAQPS) and
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TCEQ. All the counties in Texas were scored from 0 tolOO based on their nonattainment status.
Counties that are in attainment were scored 100 and counties that are in severe nonattainment
status were scored zero. The scores were assigned as follows:
Attainment Status Normalized Score
Severe Nonattainment 0
Serious Nonattainment 25
Moderate Nonattainment 50
Near Nonattainment 75
Attainment 100
2.2.3.10 RCRA TSD, Corrective Action and State VCP Sites
Data sources used for this layer include RCRA corrective action sites (in point format)
from EPA. RCRA TSD sites (in polygon and point format) from EPA and state Superfund Sites
from TCEQ (in point format). For sites where polygon data was available, the polygon data was
used otherwise a buffer of 610 m was used as a default (Sutherland 1994) and applied to the
points. All areas in the state within a buffer were scored zero and areas outside of the buffer
were scored 100. This layer was then converted to a grid with a cell size of 1 km2. These are
sites where hazardous waste was released and where there is a formal clean up process during
fiscal year 2000.
2.2.3.11 Urban/Agriculture Disturbance
Sources used for this layer were land cover types from the NLCD. Only urban/
agricultural regions over 10 ha were included. A buffer of 600 m was included around the
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urban/agriculture areas to represent disturbance to surrounding areas. This is a minimum buffer
size based on differences in road size and traffic in these developed land cover types (Sutherland
1994). The land cover types that were identified as urban and agricultural were low intensity
residential, high intensity residential, commercial/ industrial/transportation, orchards/vineyards,
pasture/hay, row crops, small grains, fallow, and urban/recreational grasses in NLCD. Using the
ArcGIS Spatial Analyst Extension, the land cover types in the NLCD were reclassified to
urban/agriculture or non-urban/agriculture. Adjacent cells of the same type were then grouped
together and the area was calculated for each region (contiguous cells of the same land cover
type). Urban/agricultural areas that were smaller than 10 ha were reclassified to non-
urban/agriculture. A buffer of 610 m was then created around the urban/agriculture areas. All
areas that are in urban/agriculture or within 610m of urban/agriculture received a score of zero.
All other areas were assigned a score of 100. This is a binary sub-layer, with scores for either
developed land cover types (urban and agriculture) scoring zero and all natural land cover types
scoring 100.
2.2.4 Accuracy Assessment
The Conservancy ecoregion portfolios for the Edwards Plateau, Southern Shortgrass
Prairie, Chihuahuan Desert, Upper West Gulf Coastal Plain, West Gulf Coastal Plain, and Gulf
Coast Prairies and Marshes were combined into a single GIS coverage. Of these portfolios,
which consist of both aquatic and terrestrial conservation areas, only aquatic portfolio areas rated
as Tier I (strong confidence that viable target populations and/or high quality system occurrences
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are present) within the Edwards Plateau and Southern Shortgrass Prairie were used since Tier II
portfolio sites have a lower conservation value primarily due to lack of ground-truthing.
The single Conservancy portfolio coverage was then converted into a grid matching the
TEAP composite grid layer specifications. To ensure a similar area of comparison, the TEAP
composite grid was clipped to mask out data for the ecoregions not yet completed by The
Conservancy (Tamaulipan Thornscrub and Crosstimbers and Southern Tallgrass Prairie).
However, it should be noted that small areas of these two ecoregions were included where
adjacent ecoregion conservation areas crossed ecoregion boundaries.
To reduce noise within the data, The Conservancy classified the data into thirty equal
classes. Each class contained ten pixel values; for example class 1 equals TEAP composite
values 1 tolO, class 2 equals TEAP composite values 11 to 20, and so on.
All the data processing was performed utilizing ArcGIS 8.3 (ESRI Inc., Redlands, CA
2001). The individual TEAP files were imported as ESRI GRID (raster) files and merged to
create four statewide grids representing Rarity, Sustainability, Diversity, and Composite. The
resulting grids were 1,183 rows by 1,245 columns with each pixel representing 1 km2.
The intersect between the TEAP composite layer and The Conservancy portfolio grids
was calculated using the raster calculator function in ArcGIS. The result was two statewide
grids, one for inside and one for outside The Conservancy combined portfolio. Summary
statistics generated for each grid layer (e.g., mean, standard deviation, count, minimum,
maximum, and sum). A frequency table of the TEAP composite pixel values was calculated and
used to compare the frequency of pixel values found inside The Conservancy portfolio versus
those found outside the portfolio. An additional map focusing on the IH69 corridor study site
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was created by clipping these three data sets to the IH69 corridor extent and recalculating the
summary statistics to generate a new frequency table.
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3.0 RESULTS
The composite map and underlying three layers are designed to assess the State of Texas
by ecoregion and to identify the optimum ecological areas for protection and mitigation based on
ecological theory (i.e., no political boundaries or regulatory programs). For presentation
purposes, this report identifies "ecological importance" as percentages of the total score
(theoretical maximum of 300) a grid cell can receive. Figures depicting the individual sub-layer
data for the entire state can be found in Appendix B.
3.1 Diversity Layer
The diversity layer was designed to show land cover continuity and diversity in Texas
(Figure 5). The statewide depiction shows a number of locations that scored in the top 1% per
ecoregion. The individual sub-layer maps can be found in Appendix B. The diversity layer
consists of four sub-layers: (1) appropriateness of land cover (Figure BIX (2) contiguous size of
undeveloped land (Figure B2\ (3) Shannon land cover diversity index (Figure B3X and (4)
significant stream segments (Figure B4).
3.2 Rarity Layer
The rarity layer was designed to show rarity of species and land cover in Texas (Figure
6). The individual sub-layer maps can be found in Appendix B. The rarity layer consists of four
sub-layers: (1) vegetation rarity (Figure B5X (2) natural heritage rank (Figure B6X (3) taxonomic
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Southern High Plains
foods
Mid Coastal
Plains, Western
Coastal Plains
and Flatwoods,
Western Gulf
Louisiana Coast
Prairies and
Marshes
Top 1 % (More Diverse)
2-10%
11 - 25%
26 - 50%
51 -100% (Less Diverse)
Rio Grande Plain
0 25 50
100
150
200
Miles
Figure 5. Map of the diversity layer with ecoregion boundaries. This map is a composite of four
sub-layers (Figures B1-B4). Even though this map shows the entire state of Texas, the measures
included in the diversity layer and subsequent composite maps (Figures 8-26) were calculated
for each ecoregion.
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Southern High Plain;
Mid Coastal
Plains, Western
. . ,.-i??^--f. '^ •:•• , :•»•/
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and Flatwoods,
Western Gulf
Louisiana Coast
Prairies and
Marshes
Top 1 % (More Rare)
2-10%
11 - 25%
26 - 50%
51 -100% (Less Rare)
Miles
Figure 6. Map of the rarity layer with ecoregion boundaries. This map is a composite of four
sub-layers (Figures B5-B8). Even though this map shows the entire state of Texas, the measures
included in the rarity layer and subsequent composite maps (Figures 8-26) were calculated for
each ecoregion.
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richness (Figure B7). and (4) rare species richness (Figure B8).
The overall rarity map shows large areas of high rarity in the Stockton Plateau, Edward's
Plateau Chihuahuan Desert Basin and Range, Mid Coastal Plains Western Section, and the
southern portion of the Rio Grande Plain (Figure 6).
3.3 Sustainability Layer
The sustainability layer (Figure 7) consists of eleven sub-layers that can be loosely
grouped into fragmentors: (1) contiguous land cover type (Figure B9). (2) regularity of
ecosystem boundary (Figure BIO). (3) appropriateness of land cover (Figure Bill (4) waterway
obstruction (Figure B12). and (5) road density (Figure B13) and stressors: (1) airport noise
(FigureB 14). (2) Superfund NPL and state Superfund Sites (Figure B15). (3) water quality
(FigureB 16). (4) air quality (Figure B17).(5) RCRA TSD. corrective action and State VCP Sites
(FigureB 18). and (6) urban/agricultural disturbance (FigureB 19). The individual sub-layer
maps can be found in Appendix B. The more sustainable areas occur where there are fewer
human disturbance activities.
3.4 Composite Layer
The composite map is the combination of the diversity, rarity, and sustainability layers
(Figure 8). The top 1% highly important ecological areas in each ecoregion in Texas are
highlighted in red. Most of the highly important ecological areas (1%, 10%) are those areas that
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Southern High Plains
Top1%
2 - 10%
11 - 25%
26 - 50%
51 -100% (Less Sustainable)
Miles
Figure 7. Map of the sustainability layer with ecoregion boundaries. This map is a composite of
eleven sub-layers (Figures B9-B19). Even though this map shows the entire state of Texas, the
measures included in the sustainability layer and subsequent composite maps (Figures 8-26)
were calculated for each ecoregion.
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Texas
High
Plains
Sacramento-
Monzano
Southern High Plains
Oak Woods
'rairies
-
. .-.Jr-. MKsLi'?: "••-Fir. :.W -Si-'
Mid Coastal
ains, Western
Coastal Plains
md Flatwoods,
.Western Gulf
Louisiana Coast
Prairies and
Marshes
150 200
Miles
Figure 8. Composite map with ecoregion boundaries. This map is a composite of the diversity
layer (Figure 5\ rarity layer (Figure 6). and sustainability layer (Figure 7). Even though this
map shows the entire state of Texas, the measures included in this map were calculated for each
ecoregion. Individual sub-layer maps for each of the three main layers can be found in
Appendix B. Those areas identified in red as the top 1% represent higher ecological importance,
those identified in white as 51-100% represent lower ecological importance.
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represent the intersection of the top 1% for diversity, rarity, and sustainability. Ecoregion results
(Figures 9-26) are explained in the following section.
3.4.1 Ecoregion Composites
Descriptions of each of the ecoregions analyzed as well as representative photos appear
in Appendix A. The following paragraphs contain brief summaries of the TEAP results by
ecoregion.
3.4.1.1 Southern High Plains
The Southern High Plains is represented by a thin section on the north edge of the Texas
panhandle. Most of the ecologically important areas (e.g., 1%, 10%, 25%) occur in the eastern
portion of this ecoregion (Figure 9).
3.4.1.2 Texas High Plains
The Texas High Plains ecoregion shows several areas with high ecological importance.
For example, the Canadian River is highlighted at the 1% and 10% levels as well as a larger
riparian buffer at the 25% level. The northwest corner and an area southeast of the Canadian
River are also highlighted and may have a high degree of rarity (Figure 10).
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0 510 20 30 40
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Miles
Figure 10. Texas High Plains composite map. A separate figure (Figure 8) shows the entire
state. Those areas identified in red as the top 1% represent higher ecological importance, those
identified in white as 51-100% represent lower ecological importance.
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3.4.1.3 Rolling Plains
The southern portion of the Rolling Plains ecoregion shows a high level of ecologically
important areas (Figure 11). Other areas representing the top 1% ecologically important areas
are scattered throughout the ecoregion and may indicate locations of high rarity.
3.4.1.4 Rio Grande Plain
The Rio Grande Plain ecoregion contains areas of high levels of ecological importance
throughout, although the northeastern portion of the ecoregion contains areas of lower
importance (Figure 12). Relatively large ecological diversity and sustainable areas can be noted
at the 10% level in this ecoregion.
3.4.1.5 RedbedPlains
The Redbed Plains is a very small, disjunct ecoregion in Texas, but extends into
Oklahoma. Most of the ecologically important areas occur in the western portion of this
ecoregion in Texas (Figure 13).
3.4.1.6 Cross Timbers and Prairie
The Cross Timbers and Prairies ecoregion shows ecological areas in the top 1% and 10%
levels in the western half of the ecoregion (Figure 14). Several important riparian areas are
noted.
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0 510 20 30 40
^
Miles
Figure 11. Rolling Plains composite map. A separate figure (Figure 8) shows the entire state.
Those areas identified in red as the top 1% represent higher ecological importance, those
identified in white as 51-100% represent lower ecological importance.
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0 5 10 20 30 40
^=
Miles
N
Figure 12. Rio Grande Plain composite map. A separate figure (Figure 8) shows the entire state.
Those areas identified in red as the top 1% represent higher ecological importance, those
identified in white as 51-100% represent lower ecological importance.
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86
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20 30
*=
Miles
Figure 14. Cross Timbers and Prairie composite map. A separate figure (Figure 8) shows the
entire state. Those areas identified in red as the top 1% represent higher ecological importance,
those identified in white as 51-100% represent lower ecological importance.
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3.4.1.7 Oak Woods and Prairies
There are ecologically important locations scattered throughout the Oak Woods and
Prairies Ecoregion (Figure 15). The northern portion of this ecoregion may include the outskirts
of large population centers such as Fort Worth. Several riparian corridors within this ecoregion
are highlighted.
3.4.1.8 Blackland Prairie
The Blackland Prairie ecoregion may be one of the least sustainable ecoregions because
of the large population centers, such as Dallas, located there; and the amount of ongoing
agricultural activities. There seems to be a noticeable difference between the northern portion
and the southern portion of this ecoregion (Figure 16). The southern portion shows much higher
levels of ecologically important areas, including noticeable riparian areas.
3.4.1.9 Mid Coastal Plains Western Section
Traditionally called the "pineywoods", the Mid Coastal Plains Western Section contains
many areas of high ecological importance (Figure 17). Primarily in the southern portion of this
ecoregion, several areas of high rarity and riparian areas are highlighted.
3.4.1.10 Coastal Plains andFlatwoods Western Gulf Section
Like the Mid Coastal Plains ecoregion, the Coastal Plains and Flatwoods Western Gulf
Section ecoregion shows several areas of ecologically importance, primarily related to a high
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Figure 15. Oak Woods and Prairies composite map. A separate figure (Figure 8) shows the
entire state. Those areas identified in red as the top 1% represent higher ecological importanc
those identified in white as 51-100% represent lower ecological importance.
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Figure 16. Blackland Prairie composite map. A separate figure (Figure 8) shows the enti
Those areas identified in red as the top 1% represent higher ecological importance, those
identified in white as 51-100% represent lower ecological importance.
entire state.
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^"™—*1L
.-. .Ttt-
Figure 17. Mid Coastal Plains Western Section composite map. A separate figure (Figure 8)
shows the entire state. Those areas identified in red as the top 1% represent higher ecological
importance, those identified in white as 51-100% represent lower ecological importance.
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degree of rarity throughout the ecoregion (Figure 18).
3.4.1.11 Edwards Plateau
The Edwards Plateau ecoregion has been studied extensively and is noted for its
ecological importance, especially in terms of rare, endemic biota. The results of the TEAP
indicate several relatively large areas in the south and southwest portions of the ecoregion due to
the high degree of rarity (Figure 19). The northeastern portion of this ecoregion has primarily
lower diversity, rarity, and sustainability. This area also includes the metropolitan center of
Austin.
3.4.1.12 Stockton Plateau
The Stockton Plateau contains several relatively large areas of highly important
ecological locations scattered throughout the ecoregion (Figure 20). These areas have a high
level of rarity as well as diversity.
3.4.1.13 Chihuahuan Desert Basin and Range
The Chihuahuan Basin and Range ecoregion is a fairly large ecoregion in West Texas.
Ecologically important areas at the 1%, 10% and 25% levels are scattered throughout the
ecoregion. A relatively large ecologically important area is located in the southern portion of
this ecoregion, representing a high degree of land cover diversity, rarity, and sustainablility
(Figure 21).
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Top1%
2 - 10%
11 - 25%
26 - 50%
51 -100%
N
0 2.5 5 10 15
*=
Miles
20
Figure 18. Coastal Plains and Flatwoods Western Gulf Section composite map. A separate
figure (Figure 8) shows the entire state. Those areas identified in red as the top 1% represent
higher ecological importance, those identified in white as 51-100% represent lower ecological
importance.
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Top 1 %
2 -10%
11 - 25%
26 - 50%
51 -100%
Figure 19. Edwards Plateau composite map. A separate figure (Figure 8) shows the entire state.
Those areas identified in red as the top 1% represent higher ecological importance, those
identified in white as 51-100% represent lower ecological importance.
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Figure 20. Stockton Plateau composite map. A separate figure (Figure 8) shows the entire state.
Those areas identified in red as the top 1% represent higher ecological importance, those
identified in white as 51-100% represent lower ecological importance.
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0 5 10 20 30 40
^t=
Miles
N
Figure 21. Chihuahuan Desert Basin and Range composite map. A separate figure (Figure 8)
shows the entire state. Those areas identified in red as the top 1% represent higher ecological
importance, those identified in white as 51-100% represent lower ecological importance.
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3.4.1.14 Sacramento-Manzano Mountain
The Sacramento-Manzano Mountain ecoregion is represented in Texas, but extends into
New Mexico and Arizona. In this small ecoregion, the highly important areas occur near the
Guadalupe Mountains (Figure 22).
3.4.1.15 Louisiana Coast Prairies and Marshes
The Louisiana Coast Prairies and Marshes ecoregion is represented as a small wedge in
eastern Texas, but extends further into Louisiana. There are a few areas that are within the top
1% and 10% for ecological importance near the Louisiana border (Figure 23).
3.4.1.16 Eastern Gulf Prairies and Marshes
The Eastern Gulf Prairies and Marshes ecoregion contains highly ecologically important
areas on the coastline in the eastern portion ecoregion (Figure 24). The Houston metropolitan
area is located on western border of this ecoregion. A relatively large ecological area with a
high degree of rarity, is located just north of Galveston Bay.
3.4.1.17 Central Gulf Prairies and Marshes
The Central Gulf Prairies and Marshes ecoregion represents a large portion of the Texas
coastline. Several important ecological areas, mostly representing riparian areas or coastal areas
appear in this ecoregion (Figure 25).
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Miles
Figure 22. Sacramento-Manzano Mountain composite map. A separate figure (Figure 8) shows
the entire state. Those areas identified in red as the top 1% represent higher ecological
importance, those identified in white as 51-100% represent lower ecological importance.
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Figure 23. Louisiana Coast Prairies and Marshes composite map. A separate figure (Figure 8)
shows the entire state. Those areas identified in red as the top 1% represent higher ecological
importance, those identified in white as 51-100% represent lower ecological importance.
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N
0 2.5 5
10
15
20
Miles
Figure 24. Eastern Gulf Prairies and Marshes composite map. A separate figure (Figure 8)
shows the entire state. Those areas identified in red as the top 1% represent higher ecological
importance, those identified in white as 51-100% represent lower ecological importance.
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Top1%
2-10%
11 - 25%
26 - 50%
51 - 100%
Figure 25. Central Gulf Prairies and Marshes composite map. A separate figure (Figure 8)
shows the entire state. Those areas identified in red as the top 1% represent higher ecological
importance, those identified in white as 51-100% represent lower ecological importance.
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3.4.1.18 Southern Gulf Prairies and Marshes
The Southern Gulf Prairies and Marshes ecoregion represents the southern portion of the
Texas coast and includes South Padre Island. Several ecologically important areas occur on the
barrier islands as well as being scattered throughout the ecoregion near the coastline (Figure 26).
3.4.2 Overlays
The TEAP results can be used in conjunction with other databases to show where public
lands (Figure 27) or transportation corridors (Figure 28) or watershed boundaries (Figure 29) are
in relation to the ecologically important areas identified using TEAP. Each TERS agency can
use the TEAP and data and overlay other GIS layers of interest. For example, Figure 29 shows
the composite TEAP map with 6-digit HUCs overlaid.
3.4.3 Accuracy Assessment
Figure 30 shows the overlap between highly ranked TEAP composite layer pixels and
The Conservancy portfolio locations. As mentioned in Section 2.0, the Tamaulipan Thornscrub
and Crosstimbers and Southern Tallgrass Prairie portfolio locations are excluded. In general,
highly scored TEAP locations corresponded to the locations of The Conservancy portfolio sites.
Correspondence was particularly high for pixels in classes 26 to 30 which represent TEAP
composite scores of 251 to 300 (Figure 3 la). At lower ranked TEAP composite layer locations,
the match between TEAP and The Conservancy portfolio sites is lower. This relationship can
also be expressed as a percentage of the TEAP pixel classes residing inside or outside The
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0 5 10 15 20
•<
Miles
Figure 26. Southern Gulf Prairies and Marshes composite map. A separate figure (Figure 8)
shows the entire state. Those areas identified in red as the top 1% represent higher ecological
importance, those identified in white as 51-100% represent lower ecological importance.
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200
Figure 27. Composite map with public lands overlay. Public lands include National and State
Parks, National Forests and Grasslands, Department of Defense lands, and National Wildlife
Refuges. Those areas identified in red as the top 1% represent higher ecological importance,
those identified in white as 51-100% represent lower ecological importance.
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200
Figure 28. Composite map with transportation corridors overlay. IH69 and Trans Texas
Corridor are included. Those areas identified in red as the top 1% represent higher ecological
importance, those identified in white as 51-100% represent lower ecological importance.
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200
Figure 29. Composite map with watershed boundary overlay. Watershed boundaries reflect 6-
digit HUCs. Those areas identified in red as the top 1% represent higher ecological importance,
those identified in white as 51-100% represent lower ecological importance.
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Classes
• -
.11
2fl
Figure 30. Map depicting areas used for the accuracy assessment. The TNC portfolio does not
include the areas in white. The scale reflects the different classes used in the accuracy
assessment. A higher class equals a higher TEAP score for that location.
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50000 i
State Composite
Outside TNC Portfolio
Inside TNC Portfolio
M illinium
M axinium
Pixel Count
9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30
1 2 3
b)
100%
93.42%
\
PH 40%
\
6.58%
1234567
9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30
Class
Frequency - Inside TNC Portfolio —•—% Frequency - Outside TNC Portfolio
Figure 31. a) Statewide frequencies of TEAP composite scores (by class) that occur inside and
outside TNC portfolio; b) statewide frequencies expressed as a percentage of TEAP composite
scores occurring inside and outside TNC portfolio. A higher class equals a higher TEAP score
for that location.
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Conservancy portfolio. For example, Figure 31b shows that 93.42% of the pixels in class 30
(TEAP scores of 291 to 300) are found inside The Conservancy portfolio, whereas only 6.58%
of the pixels in this class exist outside The Conservancy's portfolio.
A similar accuracy assessment was performed for the proposed IH69 corridor in Texas
(Figures 32 and 33). Most of the IH69 corridor is covered by The Conservancy portfolio except
for locations in south Texas (Tamaulipan Thornscrub and Crosstimbers and Southern Tallgrass
Prairie) (Figure 32). The results are similar to those seen for the entire state. Highly scored
TEAP composite layer locations (approximately classes 24 to 30) showed high correspondence
with The Conservancy portfolio sites and lower scored TEAP composite locations showed a
weaker match (Figure 33a). All TEAP composite layer pixels in the highest ranked classess
(classes 29-30) were located inside The Conservancy portfolio (Figure 33b). The opposite trend
is seen for TEAP scores located outside The Conservancy portfolio. For example, 90-100% of
the pixels in classes 1 to 7 fall outside The Conservancy porfolio. This is expected since TEAP
classified all lands in Texas whereas The Conservancy's conservation process focuses on
identifying the highest quality ecological communities only.
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Classes
•• 1
:
m
]13
zi*
j"
118
I 19
| 20
21
| 22
| 23
| 24
| 26
I 27
| 29
I 30
Figure 32. Map of proposed IH69 corridor depicting areas used for the accuracy assessment.
The scale reflects the different classes used in the accuracy assessment. A higher class equals a
higher TEAP score for that location.
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4000
a)
3500 -
3000
2500
O 2000
1500
1000
500
Mean
Mode
11.4038
10
Std. Deviation 4.5028
Minimum
Maximum
Pixel Count
1
30
33,801
77
-Corridor Composite
-Outside TNC Portfolio (1-69 corridor)
-Inside TNC Portfolio (1-69 corridor)
Mean
Mode
Std.Deviation
Minimum
Maximum
Pixel Count
10.3612
10
3.8742
1
28
25,295
9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31
12345
b)
:
: /
70%
^ 50%
<-> 40%
30%
20%
10%
\
\
\
0%
|—I—-—I
1 2 3 4 5 6 7 8 9 10 1 1 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30
Class
Frequency - Inside TNC Portfolio
—.— % Frequency - Outside TNC Portfolio
Figure 33. a) IH69 corridor frequencies of TEAP composite scores (by class) that occur inside
and outside TNC portfolio; b) IH69 corridor frequencies expressed as a percentage of TEAP
composite scores occurring inside and outside TNC portfolio. A higher class equals a higher
TEAP score for that location.
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4.0 DISCUSSION
Similar to other reports that characterize the environment at a landscape-level (H. John
Heinz III Center for Science. Economics and the Environment 2002. Schweiger et al. 2002). the
individual sub-layers and main layers selected for TEAP reflect important attributes relating to
ecosystem condition, and by extension, ecosystem function. TEAP characterizes ecological
conditions in terms of three different aspects of ecosystems using existing data coupled with
ecological theory, while recognizing that there are judgements involved in such an enterprise.
Given the complexity of ecosystems, these judgements include determining which measures to
concentrate on and which to exclude, and communicating the uncertainties and limitations of the
data and TEAP analysis.
The TEAP is a relatively simple model that uses stratified data that are combined to give
a total or composite picture of the state of Texas at the ecoregion level. Since complicated
modeling and analysis tools are less likely to be used in regulatory processes, beneficial
properties of GIS assessment tools such as TEAP include 1) simplicity (expert modeling abilities
are not needed), 2) use of available data (rather than experimentation), 3) analytical (numerical
simulation is not needed), 4) approximation (need matches level of effort), 5) measurable
change, and 6) expandability (use in more sophisticated models) (Leibowitz et al. 2000). TEAP
assesses and prioritizes locations when information is limited. Due to the scale at which the
TEAP was performed it has limitations in utility with regard to regulatory decisions or processes
requiring more detail. TEAP is a screening tool that can assist in overall conservation efforts
(including project planning, mitigation, preservation, or restoration activities) and to identify
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areas where more detailed, site-specific data are needed. TEAP results should be used in
conjunction with agency-specific information to support decisions. (Schweiger et al. 2002).
TEAP should enable managers to consider specific decisions within an ecoregion context.
4.1 Data Limitations
Several limitations of the data and analysis should be noted. No individual sub-layers
were removed a posteriori from this iteration of the protocol. The limitations and other issues
concerning specific sub-layers or their use in the protocol or their application to regulatory
processes are discussed, so that they can be modified or excluded in the next iteration of TEAP.
It was also felt that by removing individual sub-layers, the composite may only have a few
relatively non-ecological sub-layers to account for the majority of a main layer. Multivariate
evaluation of the results may yield a clearer picture of the relative contribution of each sub-layer
to each of the three main layers and the composite.
The scoring methods per layer and per ecoregion result in an issue at ecoregion
boundaries. Two adjacent cells with the same land cover type and the same stressors can score
differently in different ecoregions. For example, two cells both have a PAR of 0.123, but cell A
could get a score of 75 while cell B could receive a score of 50 because of the differences in
their respective ecoregions. The two cells could also have a composite score that is different,
even though they are basically the same. The reverse is also true; sites with the same composite
score could end up in a different category for similar reasons. Adjacent cells A and B both have
a composite score of 225, but cell A is in the top 1% cell (colored red) in its ecoregion, but cell B
scores in the top 10% cell (colored green) in an adjacent ecoregion.
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Each sub-layer within the diversity layer represents different, but somewhat overlapping,
attributes of diversity, that when combined, gives a broader picture of diversity in each
ecoregion. It can be true that there is a dichotomy between contiguous area and appropriate land
cover. These are reasons why the TEAP (and CrEAM) is a stratified approach (i.e., equally-
weighted sub-layers feed into layers which are then combined into a composite).
Kuchler (1964) data was used in the diversity and sustainability layers. The comparison
between the PNV (Kuchler 1964) and 1992 NLCD is the most common method of describing the
original spatial distribution of land cover and current conditions (Geneletti 2003). In addition,
maintaining vegetation in proportion to its former, pre-settlement abundance is a goal of
biodiversity conservation (Geneletti 2003).
The TXBCD is an observational data set that does not specifically consider communities.
It is not comprehensive or synoptic like the GIS coverages. This is the reason that the TXBCD
(or any other individual sub-layer, for that matter) was not used to exclusively represent rarity,
but was combined with vegetation rarity (using NLCD). and is included as a separate sub-layer
of equal weight in the rarity main layer. Other studies use measures of rarity, and highlight its
relevance, especially for biodiversity conservation. However, there is no consensus on the
attributes to include for its evaluation (Geneletti 2003).
Actual habitat information is better than somewhat arbitrary buffers around species
observation points. However, this type of data does not exist statewide, although gap analysis
data may be available in the future to address this concern. Other databases or scientific studies
may exist, but did not meet the general guideline of TEAP to use pre-existing data that was
available statewide. The reason for not using localized study data is to avoid the bias that results
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because some species are better studied than others. For example, a great deal is known about
the organisms that inhabit the Edwards Aquifer and recharge zone of the Edwards Plateau
ecoregion (Figure 19). However, biota in other portions of this ecoregion may not be as well
studied or have systematic data available. EPA Region 5 found a similar situation in its analysis
where one state had a much more active monitoring and data collection program than other
states. EPA Region 5 addressed this by using multiple measures or sub-layers to characterize
rarity.
The TEAP sub-layers do not explicitly account for supporting habitat for species (versus
the actual observation point), although the contiguous size of undeveloped land (Figure B2)
describes polygons of adjacent undeveloped land cover types. While it is correct that any land
cover patch is generally influenced in some way by its adjacent neighboring patches, the TEAP
is not able to explicitly incorporate adjacency effects as would be possible in a dynamic
simulation model. The TEAP is a static model which characterizes the landscape through a
mono-temporal multi-criteria evaluation approach. Detailed spatial and temporal dynamics
between landscape patches cannot be modeled in this class of static models. Given the goals and
objectives of TERS. it is unlikely that a dynamic model would provide a better solution than the
type of model used.
Unlike EPA Region 5, Texas does not contain any natural lakes (other than isolated playa
basins). Therefore, the open water land cover types (i.e., reservoirs) had to be excluded from
sustainability sub-layers such as regularity of ecosystem boundary. It is a long and tedious
manual process in GIS to "mask out" these areas so that only the shoreline was used. Including
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the entire area of these reservoirs (rather than just the shoreline) could tend to skew the area
included in the one percentile fraction of the total area in an ecoregion.
The watershed obstruction sub-layer calculates dams per stream miles within each HUC
whereas the water quality sub-layer uses actual stream segments. These two sub-layers should
be more consistent in the next iteration because both could use stream segments (vs HUC5).
However, a significant amount of technical assistance would be required to modify the
calculations for these two layers for the next iteration of TEAR
The road density sub-layer did not intentionally include or exclude water bodies. Cells
that had zero roads scored 100, therefore cells that are all water are scored 100 (predominately
found in the coastal areas).
In the urban/agriculture disturbance sub-layer (FigureB19\ a 600 m buffer around urban
and agricultural areas may tend to mask the presence of riparian and greenbelt areas. Though
highly susceptible to development pressures, these areas may be among the most important to
maintain and protect, especially for adequate water quality necessary to sustain aquatic species
and to reduce downstream pollutant transport. TEAP is not intended to discourage use or
designation of buffer zones around riparian, urban, or recreation areas. TEAP should point out
places for conservation and enhancement (especially in terms of potentially restoring landscape
connectivity) in areas that are currently not sustainable without intensive human management.
Given the available data and timeline, the EPA Region 5 model was at a scale (300 m2)
that allowed them to pick out a single or a few pixels of important ecological areas in or near
cities (e.g., within the top 25% of all sites in the midwest.). This iteration of TEAP did not use
such a fine scale resolution because of data quality and computer calculation time.
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4.2 Accuracy Assessment
The accuracy assessment was performed by The Conservancy, an independent entitynoy
involved with the calculations of the TEAP main and composite layers. The portfolio sites used
in the accuracy assessment were derived independently from the TEAP using The Conservancy's
process. Both TEAP and The Conservancy's processes use GIS information at some level;
however, The Conservancy's process also includes field investigations whereas TEAP does not.
As explained in the results section, the match between The Conservancy's portfolio sites and
highly scored TEAP composite locations is good; however, there is less of a match at lower
TEAP scores. This may be due to the fact that The Conservancy's process is designed to
identify the highest quality or rare ecological communities for protection rather than identifying
lower quality sites for restoration or mitigation process opportunities. It is difficult to determine
the degree or "goodness" of the match between TEAP and The Conservancy without further
field investigations. The decision to proceed with field investigations depends on the priority of
such investigations for the TERS member agencies and the usefulness of these lower scored
TEAP composite locations to agency programs (e.g., agencies looking for restoration
opportunities).
Further analysis using multivariate statistics is needed to further verify the results of
TEAP. Future actions such as the application of landscape metrics to study the pattern found at
a finer resolution are also recommended to understand the spatial landscape patterns (McGarigal
and Marks 1994. Riitters et al. 1995. Hargisetal. 1998. Roy and Tomar 2000. Herzog et al.
2001. Lee etal. 2001. Ochoa-Gaona2001. Lausch and Herzog 20021
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4.3 Conservation
TEAP uses generally accepted ecological theory as the basis for its analysis. However,
an aspect that affects potential conservation and protection of ecologically important locations in
Texas regards the protection of large contiguous tracts of land versus protection of small high-
value remnants that are possibly unsustainable areas without intense human management. The
argument of protecting Several Small or Single Large areas/reserves (SLOSS) has been
discussed considerably in the scientific literature (see Ovaskainen 2003). In the end, questions
related to the spatial configuration of reserves and how the surrounding matrix was managed
became more important as conservation goals.
Conservation is not the primary mission of many regulatory agencies. For these
agencies, the TEAP may be useful in meeting NEPA requirements and in making project
planning level analyses and decisions.
It seems obvious that planners should avoid negatively impacting ecologically important
areas, especially in areas where there are few ecologically important areas remaining. On the
other hand, the most threatened and rarest species and communities are often found in areas that
TEAP would identify as less important. The key is to strike a balance between protecting and
enhancing highly ecologically important areas versus protecting and enhancing vulnerable
species/communities in less ecologically important areas.
Eventually, the decision should be determined by several factors. Ovaskainen (2003)
suggested that the SLOSS decision should promote 1) maximizing the number of species that
will eventually survive, 2) maximizing the number of currently occurring species, 3) lengthening
species time to extinction, and 4) maximizing metapopulation capacity. Similarly, Noss and
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Csuti (1994) proposed that 1) critical ecological processes must be maintained, 2) goals and
objectives must come from an ecological understanding of the system, 3) external threats must
be minimized and external benefits maximized, 4) evolutionary processes should be conserved,
and 5) management must be adaptive and minimally intrusive. Harris et al. (1996) and Noss
(1996) suggest a connectivity approach to protect landscapes from further fragmentation and to
restore connectivity to culturally fragmented landscapes, where possible. Linking such areas
may enhance landscape connectivity (e.g., organism dispersal, optimal foraging areas) and
reduce the effects of fragmentation (Beier and Noss 1998. Hoctor et al. 2000. Swenson and
Franklin 2000).
The ecologically important areas identified through TEAP do not represent areas that, if
left undisturbed, would capture all of the remaining biodiversity in the state, nor does it give
license to destroy areas that have lower TEAP scores of ecological importance. The use of
TEAP would be the first step in avoidance of impacts, not the last. TEAP identifies the top 1%
ecologically important areas in each ecoregion and provides information to aid streamlining
agency decisions used to protect the biodiversity of Texas. When communicating with decision-
makers concerning the results of TEAP. protecting (or avoiding) every square inch of an area
falling in the 1% category does not necessarily protect biodiversity per se. It can, however, help
protect places that make a significant contribution to the biodiversity of Texas.
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5.0 CONCLUSIONS
5.1 Streamlining
The TEAP effort supports streamlining and the EO 13274 by providing a tool agencies
can use to rapidly assess some of the environmental impacts of large projects, including
transportation projects. The TEAP accomplishes one of the goals of TERS, which is to develop
an ecosystem-based tool to assist in identifying important ecological areas in the state for use in
the planning of large scale projects. It may also aid in alternatives analysis, some compensatory
mitigation, and preservation.
Another goal of the TERS is to improve the overall quality of agency decision-making,
with respect to the environmental concerns, in the state of Texas. The information provided by
TEAP better informs agencies facilitating better decisions.
5.2 Next Steps
Large-scale projects present many special problems. The following are obstacles to
achieving adequate mitigation of environmental impacts: 1) They often affect diverse habitats,
land forms and watersheds, 2) Adequate amounts or types of lands needed for appropriate
compensatory action may not be easily accessible, and 3) They may intersect numerous
regulatory agency jurisdictions that must be addressed (Reid and Murphy 1995). Linear projects
are a special challenge because the avoidance of impacts in one segment may define the impact
in the next. Identification of the most important resources present for an entire project is a tool
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that can be used to avoid impacts, minimize impacts, identify potential compensatory mitigation,
and select the least environmental damaging project alternative.
Large projects such as IH69, challenge agency staffing, funding, and the ability to
provide timely decisions if conducted in a "business-as-usual" manner. Regulatory agency
authority and policy may or may not provide guidance to deal with the demands associated with
very large and complex projects.
In the past, impacts of public works projects have not been evaluated on an ecoregion
scale in Texas. Inclusion of ecoregion information, such as that found in the TEAP. into the
planning process of large public works projects facilitates project impact analysis and the
mitigation of impacts while realizing conservation of ecologically important lands. This tool
may help streamline the project development process through early identification of project
impacts, and enhances the capability of avoidance and minimization of those impacts.
TEAP has great potential for enhancing environmental impact analysis. However, it still
needs to be validated. TEAP should be updated approximately every two years to maximize
utility. This will allow the performance of trend analysis as new data becomes available. The
results described in this report can be used in discussions for mitigation opportunities and
identification of key locations for more effective species protection (Abbitt et al. 2000). For
example, TEAP information can be of assistance in locating, designing and establishing
mitigation areas, mitigation banks, or other conservation areas. Finally, TEAP identifies
strategic indicators that can be modified in subsequent iterations, can be compared across time
periods, can potentially serve as reference points for project and long range planning, and can
provide supplemental data to aid in regulatory discussions. TEAP is not designed to take the
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place of agency policies and procedures, but to be a supplemental information tool to aid in
agency decision making.
6.0 ACKNOWLEDGMENTS
The TERS Steering Committee would like to thank the following individuals who also provided
input to the TEAP process: Mark Ball (TXDQI), Kathy Boydston (TPWD), Dale Davidson
(USAGE). Andrea Donio (TPWD). Lee Elliott (The Nature Conservancy). Luis Fernandez
(EPA). Jeff Francell (TPWD). Presley Hatcher (USAGE). Everett Laney (USAGE). Wayne Lea
(USAGE). Mike Leary (FHWA). David A. Manning (USAGE). Jessica Napier (USAGE).
Dianna Noble (TXDOT). Irene Rico (FHWA), Jeanne Roddy (TXDOT). Jeff Saitas (TCEO).
Terri Seales (TCEO). Steve Swihart (USAGE). Tom Weber (TCEO). and Mary White (EPA).
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APPENDIX A
Descriptions of Bailey's Ecoregions
(McNab and Avers 1994)
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Table of Contents
Chapter Page
Southeastern Mixed Forest 140
Mid Coastal Plains. Western (Section 23 IE) 140
Geomorphology 140
Lithology and Stratigraphy 140
Soil Taxa 140
Potential Natural Vegetation 141
Fauna 141
Climate 141
Surface Water Characteristics 141
Disturbance Regimes 141
Land Use 141
Eastern Gulf Prairies and Marshes (Section 23 IF) 141
Geomorphology 141
Lithology and Stratigraphy 142
Soil Taxa 142
Potential Natural Vegetation 142
Fauna 143
Climate 143
Surface Water Characteristics 143
Disturbance Regimes 143
Land Use 143
Outer Coastal Plain Mixed Forest 143
Louisiana Coast Prairies and Marshes (Section 232E) 143
Geomorphology 143
Lithology and Stratigraphy 144
Soil Taxa 144
Potential Natural Vegetation 144
Fauna 144
Climate 145
Surface Water Characteristics 145
Disturbance Regimes 145
Land Use 145
Coastal Plains and Flatwoods. Western Gulf (Section 232F) 145
Geomorphology 145
Lithology and Stratigraphy 146
Soil Taxa 146
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Potential Natural Vegetation 146
Fauna 146
Climate 146
Surface Water Characteristics 147
Disturbance Regimes 147
Land Use 147
Prairie Parkland (Subtropical) 147
Cross Timbers and Prairies (Section 255 A) 147
Geomorphology 147
Lithology and Stratigraphy 148
Soil Taxa 148
Potential Natural Vegetation 148
Fauna 148
Climate 148
Surface Water Characteristics 148
Disturbance Regimes 149
Land Use 149
Blackland Prairies (Section 25 5B) 149
Geomorphology 149
Lithology and Stratigraphy 149
Soil Taxa 149
Potential Natural Vegetation 150
Fauna 150
Climate 150
Disturbance Regimes 150
Land Use 150
Oak Woods and Prairies (Section 255O 150
Geomorphology 150
Lithology and Stratigraphy 151
Soil Taxa 151
Potential Natural Vegetation 151
Fauna 151
Climate 152
Surface Water Characteristics 152
Disturbance Regimes 152
Land Use 152
Central Gulf Prairies and Marshes (Section 25 5D) 152
Geomorphology 152
Lithology and Stratigraphy 153
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Soil Taxa 153
Potential Natural Vegetation 153
Fauna 153
Climate 153
Surface Water Characteristics 153
Disturbance Regimes 154
Land Use 154
Great Plains Steppe and Shrub 154
Redbed Plains (Section 311 A) 154
Geomorphology 154
Lithology and Stratigraphy 155
Soil Taxa 155
Potential Natural Vegetation 155
Fauna 155
Climate 155
Surface Water Characteristics 155
Disturbance Regimes 155
Land Use 155
Southwest Plateau and Plains Dry Steppe and Shrub 156
Texas High Plains (Section 3 \5E} 156
Geomorphology 156
Lithology and Stratigraphy 156
Soil Taxa 156
Potential Natural Vegetation 156
Fauna 156
Climate 157
Surface Water Characteristics 157
Disturbance Regimes 157
Land Use 157
Rolling Plains (Section 315O 158
Geomorphology 158
Lithology and Stratigraphy 158
Soil Taxa 158
Potential Natural Vegetation 159
Fauna 159
Climate 159
Surface Water Characteristics 159
Disturbance Regimes 159
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Land Use 159
Edwards Plateau (Section 315D} 159
Geomorphology 159
Lithology and Stratigraphy 160
Soil Taxa 160
Potential Natural Vegetation 160
Fauna 160
Climate 161
Surface Water Characteristics 161
Disturbance Regimes 161
Land Use 161
Rio Grande Plain (Section 315E^ 161
Geomorphology 161
Lithology and Stratigraphy 161
Soil Taxa 161
Potential Natural Vegetation 162
Fauna 162
Climate 163
Surface Water Characteristics 163
Disturbance Regimes 163
Land Use 163
Southern Gulf Prairies and Marshes (Section 315F) 163
Geomorphology 163
Lithology and Stratigraphy 164
Soil Taxa 164
Potential Natural Vegetation 164
Fauna 164
Climate 164
Surface Water Characteristics 164
Disturbance Regimes 165
Land Use 165
Arizona-New Mexico Mountains Semi-Desert - Open Woodland - Coniferous Forest - Alpine
Meadow ' 165
Sacramento-Manzano Mountain (Section M313B) 165
Geomorphology 165
Lithology and Stratigraphy 165
Soil Taxa 166
Potential Natural Vegetation 166
Climate 166
Surface Water Characteristics 166
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Disturbance Regimes 166
Cultural Ecology 166
Chihuahuan Semi-Desert 167
Basin and Range (Section 321A) 167
Geomorphology 167
Lithology and Stratigraphy 168
Soil Taxa 168
Potential Natural Vegetation 168
Climate 168
Surface Water Characteristics 168
Disturbance Regimes 169
Land Use 169
Cultural Ecology 169
Stockton Plateau (Section 32IE) 169
Geomorphology 169
Lithology and Stratigraphy 170
Soil Taxa 170
Potential Natural Vegetation 170
Fauna 170
Climate 171
Surface Water Characteristics 171
Disturbance Regimes 171
Land Use 171
Great Plains-Palouse Dry Steppe 171
Southern High Plains (Section 33 IE) 171
Geomorphology 171
Lithology and Stratigraphy 172
Soil Taxa 172
Potential Natural Vegetation 172
Fauna 172
Climate 172
Surface Water Characteristics 172
Land Use 172
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Southeastern Mixed Forest
Mid Coastal Plains, Western (Section 231E)
Photo courtesy Texas Parks and Wildlife Dept. O2003
Geomorphology. This Section is in the Coastal Plains geomorphic province. The predominant
landform occupying about 80% of the Section consists of moderately dissected irregular plains
of marine origin. The plains were formed by deposition of continental sediments onto
submerged, shallow continental shelf, which was later exposed by sea level subsidence. Other
landforms consist of plains with hills and smooth plains. Elevations range from 80 to 650 ft (25
to 200 m). Local relief ranges from 100 to 300 ft (30 to 90 m).
Lithology and Stratigraphy. Rock units formed during the Cenozoic Era. Strata consist of
Tertiary marine deposits (glauconitic sands and clays with lenses of coquinid limestone; clay and
silty clay).
Soil Taxa. Soils are predominantly Udults. Paleudults, Hapludults, Hapludalfs, Paleudalfs, and
Albaqualfs are on uplands. Fluvaquents, Udifluvents, Eutrochrepts, and Glossaqualfs are on
bottom lands along major streams. Soils have a thermic temperature regime, a udic moisture
regime, and siliceous or mixed mineralogy. Most soils have formed from sandstone and shale
parent materials. Soils are generally coarse textured, deep, and have adequate moisture for plant
growth during the growing season.
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Potential Natural Vegetation. Kuchler mapped this area as oak-hickory-pine forest, southern
mixed forest, and southern floodplain forest. The predominant vegetation form consists of
needle-leaved evergreen trees. Belts of cold deciduous, broad-leaved hardwoods are prevalent
along rivers. The principal forest cover type is loblolly and longleaf pines. Where hardwoods
are prevalent, species consist of post, white, blackjack, and southern red oaks. Species of bottom
lands are red maple, green ash, Nuttall oak, sweetgum, and swamp hickory.
Fauna. The elk, mountain lion, wolf, Carolina parakeet, and ivory-billed woodpecker once
inhabited this Section. Presently, the fauna include white-tailed deer, black bear, bobcat, gray
fox, raccoon, cottontail rabbit, gray squirrel, fox squirrel, striped skunk, swamp rabbit, and many
small rodents and shrews. The turkey, bobwhite, and mourning dove are game birds in various
parts of this Section. In flooded areas, ibises, cormorants, herons, egrets, and kingfishers are
common. Songbirds include the red-eyed vireo, cardinal, tufted titmouse, wood thrush, summer
tanager, blue-gray gnatcatcher, hooded warbler, and Carolina wren. The herpetofauna include
the box turtle, common garter snake, and timber rattlesnake.
Climate. Annual precipitation averages 40 to 54 inches (1,000 to 1,300 mm). Temperature
averages 61 to 68 F (16 to 20 CT). The growing season lasts about 200 to 270 days.
Surface Water Characteristics. There is a moderate density of small to medium size perennial
streams and associated rivers, most with moderate volume of water flowing at low velocity.
Dendritic drainage pattern has developed. Major rivers draining this Section include the Red and
Ouachita.
Disturbance Regimes. Fire has probably been the principal historical disturbance. Climatic
influences include occasional summer droughts and winter ice storms, and infrequent hurricanes.
Insect disturbances are often caused by southern pine beetles.
Land Use. Natural vegetation has been cleared for agriculture on about 25% of the area. Much
of the non-cleared land is managed for forestry.
Eastern Gulf Prairies and Marshes (Section 231F)
Geomorphology. This Section is in the Coastal Plains geomorphic province. The predominant
landform is a flat, weakly dissected alluvial plain formed by deposition of continental sediments
onto submerged, shallow continental shelf, which was later exposed by sea level subsidence.
Along the coast, fluvial deposition and shore zone processes are active in developing and
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maintaining beaches, swamps, and mud flats. Elevation ranges from 10 to 330 ft (3 to 100 m).
Local relief ranges from 0 to 100 ft (0 to 30 m).
Lithology and Stratigraphy. Rock units formed during the Cenozoic Era. Strata consist of
Quaternary marine deposits (non-glacial sand, silt, and clay deposits of upland origin).
Soil Taxa. Aquolls, Saprists, Aquents, and Hemists are the principal soils along the coast. Also
along the coast are Aquolls, Haplaquolls, Medisaprists, Hydraquents, and Medihemists, all of
which are poorly drained and subject to flooding and high water tables. These soils have a
thermic temperature regime and an aquic moisture regime. Farther inland, Uderts and Aqualfs
are the main soils, especially where saline prairie vegetation is present. Soils farther inland on
low lands are Pelluderts, Pellusterts, Albaqualfs, Ochraqualfs, and Glossaqualfs. Situated on
flood plains are Argiaquolls, Haplaquolls, and Haplaquepts. Soils have a thermic to
hyperthermic moisture regime, and an aquic moisture regime. These soils are deep, clayey,
poorly drained, and have subsoils that are slowly permeable.
Photo courtesy Texas Parks and Wildlife Dept. O2003
Potential Natural Vegetation. Kuchler classified vegetation as bluestem-sacahuista prairie and
southern cordgrass prairie. Predominant vegetation is mid to tall grass grasslands. Species
consist of little bluestem, indiangrass, switchgrass, and big bluestem. Occasional areas of live
oak are present. Poorly drained areas along the coast support freshwater and saltwater marsh
vegetation of sedges, rushes, saltgrass, and cordgrass.
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Fauna. Typical large herbivores and carnivores include manatee, coyote, red wolf, ringtail,
ocelots, and river otter. Smaller herbivores include swamp rabbit, fulvous harvest mouse,
eastern wood rat, and nutria. Common birds of freshwater marshes, lakes, ponds, and rivers
include reddish egret, white-faced ibis, white-fronted goose, and olivaceous cormorant.
Attwater's prairie chicken was once common in the grasslands. Reptiles and amphibians include
American alligator, Gulf coast salt marsh snake, Gulf coast toad and pig frog, diamondback
terrapin, Mediterranean gecko, and the Texas horned lizard.
Climate. Average annual precipitation is from 30 to 55 inches (750 to 1,400 mm). Temperature
averages 66 to 74 F (19 to 23 C°). The growing season lasts 250 to 330 days.
Surface Water Characteristics. There is a moderate density of small to medium size perennial
streams and very low density of associated rivers; most have a moderate volume of water at very
low velocity. Water table is high in many areas, resulting in poor natural drainage and
abundance of wetlands. Poorly defined drainage pattern has developed on this very young,
weakly dissected plain. Abundance of palustrine systems having seasonally high water level.
This Section adjoins the Louisianian Marine and Estuarine Province delineated by the USDI
FWS.
Disturbance Regimes. Fire and ocean tides have likely been the principal historical disturbance.
Climatic influences include occasional hurricanes.
Land Use. Natural vegetation has been cleared for agricultural crops on about 40% of the area.
Outer Coastal Plain Mixed Forest
Louisiana Coast Prairies and Marshes (Section 232E)
Geomorphology. This Section is in the Coastal Plains geomorphic Province. The predominant
landform is a flat, weakly dissected alluvial plain formed by deposition of continental sediments
onto submerged, shallow continental shelf, which was later exposed by sea level subsidence.
Along the coast, fluvial deposition and shore zone processes are active in developing and
maintaining beaches, swamps, and mud flats. Elevation ranges from 0 to 160 ft (0 to 50 m).
Local relief ranges from 0 to 50 ft (0 to 15 m).
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Photo courtesy Texas Parks and Wildlife Dept. O2003
Lithology and Stratigraphy. Rock units formed during the Cenozoic Era. Strata consist of
Quaternary marine deposits of terrestrial origin, non glacial sand, silt, and clay.
Soil Taxa. Aquolls, Saprists, Aquents, and Hemists are the principal soils along the coast. Also
along the coast are Aquolls, Haplaquolls, Medisaprists, Hydraquents, and Medihemists, all of
which are poorly drained and subject to flooding and high water tables. These soils have a
thermic temperature regime and an aquic moisture regime.
Potential Natural Vegetation. Kuchler classified vegetation as bluestem-sacahuista prairie and
southern cordgrass prairie. Much of the existing vegetation is nonforested grasslands. Prairie
grasslands dominate areas inland from the coast and consist of little bluestem, indiangrass,
switchgrass, and big bluestem. Occasional areas of live oak are present. Poorly drained areas
along the coast support freshwater and saltwater marsh vegetation of sedges, rushes, saltgrass,
and cordgrass.
Fauna. Large herbivores and carnivores include manatee, coyote, red wolf, ringtail, and river
otter. Ocelots were once common, but are now rare. Smaller herbivores include swamp rabbit,
fulvous harvest mouse, eastern wood rat, and nutria. Birds of fresh water marshes, lakes, ponds,
and rivers include reddish egret, white-faced ibis, white-fronted goose, and olivaceous
cormorant. Birds of grasslands include Attwater's prairie chicken. Reptiles and amphibians
include the Gulf coast salt marsh snake, Gulf coast toad, pig frog, American Alligator,
diamondback terrapin, Mediterranean gecko, and Texas horned lizard.
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Climate. Annual precipitation averages 25 to 55 inches (620 to 1,400 mm). Temperature
averages 68 to 70 F (20 to 21 CT). The growing season lasts 280 to 320 days.
Surface Water Characteristics. There is a moderate density of small to medium size perennial
streams and very low density of associated rivers, most with moderate volume of water at very
low velocity. Water table is high in many areas, resulting in poor natural drainage and an
abundance of wetlands. The Mississippi River flows through this Section into the Gulf of
Mexico. Palustrine systems are abundant and have seasonally high water levels. This Section
adjoins the Louisianian Marine and Estuarine Province delineated by the USDIFWS.
Disturbance Regimes. Fire and ocean tides have probably been the principal historical
disturbance. Climatic influences include occasional hurricanes.
Land Use. Natural vegetation has been converted to agricultural crops on about 40% of the area.
Coastal Plains and Flatwoods, Western Gulf (Section 232F)
Photo courtesy Texas Parks and Wildlife Dept. O2003
Geomorphology. This Section is in the Coastal Plains geomorphic province. The predominant
landform consists of weakly to moderately dissected irregular plains of alluvial origin formed by
deposition of continental sediments onto a submerged, shallow continental shelf, which was later
exposed by sea level subsidence. Along the coast, fluvial deposition and shore zone processes
are active in developing and maintaining beaches, swamps, and mud flats. About 80% of this
Section consists of irregular plains. Other landforms include flat plains and plains with hills.
Elevation ranges from 80 to 660 ft (25 to 200 m). Local relief mostly ranges from 100 to 300 ft
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(30 to 90 m) on irregular plains; however, relief ranges from 0 to 100 ft (0 to 30 m) on flat plains
and 300 to 500 ft (90 to 150 m) where plains with hills are present.
Lithology and Stratigraphy. Rocks in this Section formed during the Cenozoic Era. About 80%
of the geologic strata consist of Tertiary marine deposits, including glauconitic, calcareous, and
fossiliferous strata with lignitic sandy and argillaceous contents. Quaternary marine deposits are
present along the Red River.
Soil Taxa. Soils are mostly Udults. Paleudults, Hapludults, Hapludalfs, Paleudalfs, and
Albaqualfs are on uplands. Fluvaquents, Udifluvents, Eutrochrepts, and Glossaqualfs are along
major streams. Soils are mostly derived from weathered sandstone and shale. Soils have a
thermic temperature regime, a udic moisture regime, and siliceous or mixed mineralogy. Soils
are deep, coarsely textured, mostly well drained, and have an adequate supply of moisture for
use by vegetation during the growing season.
Potential Natural Vegetation. Kuchler mapped vegetation as southern mixed forest, oak-
hickory-pine forest, and southern flood plain forest. The predominant vegetation form is
evergreen needle-leaved forest with a small area of cold-deciduous alluvial forest. The slash
pine and longleaf pine cover type dominates most of the Section. The loblolly pine-shortleaf
pine cover type is common in the northern parts of the Section. A bottomland type is prevalent
along most major rivers and consists of cottonwood, sycamore, sugarberry, hackberry, silver
maple, and red maple.
Fauna. The elk, mountain lion, wolf, Carolina parakeet, and ivory-billed woodpecker once
inhabited this Section. The endangered Florida panther may be encountered rarely. Presently,
the fauna include white-tailed deer, black bear, bobcat, gray fox, raccoon, cottontail rabbit, gray
squirrel, fox squirrel, striped skunk, swamp rabbit, and many small rodents and shrews. The
presence of turkey, bobwhite, and mourning dove is widespread. Resident and migratory
nongame bird species are numerous, as are species of migratory waterfowl. In flooded areas,
ibises, cormorants, herons, egrets, and kingfishers are common. Songbirds include the red-eyed
vireo, cardinal, tufted titmouse, wood thrush, summer tanager, blue-gray gnatcatcher, hooded
warbler, and Carolina wren. The endangered red-cockaded woodpecker and bald eagle inhabit
this Section. The herpetofauna include the box turtle, common garter snake, eastern
diamondback rattlesnake, timber rattlesnake, and American alligator.
Climate. Precipitation averages 40 to 54 inches (1,020 to 1,350 mm) annually. Annual
temperature averages 61 to 68 F (16 to 20 CT). The growing season lasts 200 to 270 days.
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Surface Water Characteristics. This Section has a moderate density of small to medium size
perennial streams and associated rivers. Dendritic drainage pattern has developed without
bedrock structural control. Major rivers include the Sabine, Red, and Mississippi.
Disturbance Regimes. Fire has probably been the principal historical disturbance. Climatic
influences include occasional summer droughts and winter ice storms and infrequent hurricanes.
Insect disturbances are often caused by southern pine beetles.
Land Use. Natural vegetation has been cleared for agriculture on about 60% of the area.
Prairie Parkland (Subtropical)
Cross Timbers and Prairies (Section 255A)
Photo courtesy Texas Parks and Wildlife Dept. O2003
Geomorphology. This Section is in the Central Lowlands geomorphic province. The
predominant landform on about 70% of the Section consists of irregular plains that originated
from uplift of level bedded continental sediments, that had been deposited into a shallow inland
sea, followed by a long period of erosion. Other landforms include plains with hills and open
high hills. Elevation ranges from 330 to 1,300 ft (100 to 400 m). Local relief ranges from 100
to 300 ft (30 to 90 m).
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Lithology and Stratigraphy. Rock units were formed during the Paleozoic (30%) and Mesozoic
(70%) Eras. Paleozoic strata consist of Pennsylvanian marine deposits (sandstone, shale, coal,
and limestone). Mesozoic strata consist of Lower Cretaceous marine deposits (limestone).
Soil Taxa. Soils in the Cross Timbers region are mainly Ustalfs. Paleustalfs and Haplustalfs are
on uplands. Ustifluvents and Haplustolls are on narrow flood plains. Soils have a thermic
temperature regime, a ustic moisture regime, and mixed or siliceous mineralogy. Soils are deep,
well drained, and moderate textured; moisture is limited for use by vegetation during part of the
growing season. Soils in the Prairie region are Ustolls, Userts, and Ochrepts. Pellusterts and
Chromusterts are on upland valleys. Calciustolls are on smooth uplands. Haplustolls,
Calciustolls, and Argiustolls are on areas of limestone parent material. Ustochrepts and
Calciustolls occur on steep plateau sideslopes. Haplustolls are on flood plains. Argiustolls and
Haplustalfs are on smooth uplands in northern areas of the Section. Soil temperature regime is
thermic, moisture regime is ustic, and mineralogy is montmorillonitic, mixed, or carbonatic.
Generally, soils are deep, fine textured, and well drained; moisture is limited for use by
vegetation during parts of the growing season.
Potential Natural Vegetation. Kuchler classified vegetation as cross timbers (Quercus-
Andropogon), oak-hickory forest, and oak-hickory-pine forest. The predominant vegetation
form is cold-deciduous broad-leaved forest and extensive areas of tall grassland with a tree layer.
Forest cover consists of post, live, and blackjack oaks, and pignut and mockernut hickories.
Grasses consist of big and little bluestems, indiangrass, and sunflower.
Fauna. Among the fauna in this Section are white-tailed deer, black bear, bobcat, gray fox,
raccoon, cottontail rabbit, gray squirrel, fox squirrel, eastern chipmunk, white-footed mouse,
pine vole, short-tailed shrew, and cotton mouse. The turkey, bobwhite, and mourning dove are
game birds in various parts of this Section. Songbirds include the red-eyed vireo, cardinal,
tufted titmouse, wood thrush, summer tanager, blue-gray gnatcatcher, hooded warbler, and
Carolina wren. The herpetofauna include the box turtle, common garter snake and timber
rattlesnake.
Climate. Precipitation averages 35 to 40 inches (900 to 1,050 mm). About 5 to 18 inches (120
to 450 mm) of snow falls annually. Temperature averages 55 to 63 F (13 to 17 CT). The
growing season lasts 190 to 235 days.
Surface Water Characteristics. This Section has a low to moderate density of perennial streams
and associated rivers, mostly with low to moderate rates of flow and moderate velocity.
Dendritic drainage patterns have developed. One of the major rivers draining this Section is the
Red River. A relatively large number of water reservoirs have been constructed.
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Disturbance Regimes. Fire and drought have probably been the principal historical sources of
disturbance.
Land Use. Natural vegetation has been cleared for agricultural crops on about 75% of the area.
Blackland Prairies (Section 255B)
Photo courtesy Texas Parks and Wildlife Dept. O2003
Geomorphology. This Section is in the Coastal Plains geomorphic province. The predominant
landform is irregular plains. This Section is an elevated sea bottom that has been shaped by
marine and shore-zone processes resulting from repeated episodes of submergence and
emergence of the land from the ocean. Some geomorphic processes currently active throughout
the area are gentle gradient valley stream erosion, transport and deposition. Elevation ranges
from 330 to 660 ft (100 to 200 m). Local relief ranges from 100 to 300 ft.
Lithology and Stratigraphy. Rock units in this Section formed during the Mesozoic (10%) and
Cenozoic (90%) Eras. Mesozoic strata consist of Upper Cretaceous marine deposits (shales,
marls, and chalks). Cenozoic strata consists of Tertiary marine deposits.
Soil Taxa. Soils are Usterts, Ustolls, Aqualfs, and Ustalfs. Pellusterts are in upland valleys.
Chromusterts are on eroded uplands. Haplustrolls and Ustorthents are along an Austin chalk
escarpment. Calciustolls and Haplustolls are along stream terraces. Albaqualfs, Ochraqualfs,
and Paleustalfs are on uplands. Pelluderts, Haplaquolls, and Chromusterts are on flood plains.
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These soils have a thermic temperature regime, a ustic or aquic moisture regime, and
montmorillonitic or mixed mineralogy. Generally, soils are deep, mostly well drained, medium
to fine textured, and have limited soil moisture supplies for use by vegetation during parts of the
growing season.
Potential Natural Vegetation. Kuchler mapped vegetation as blackland prairie (Andropogon-
Stipa) and juniper-oak savanna. The predominant vegetation form is tall grassland consisting
mainly of bunch grasses, such as indiangrass, big bluestem, switchgrass, and eastern gamagrass.
A savanna community occurs along many major rivers, consisting of elm, pecan, cottonwood,
and hackberry, with grasses between the trees.
Fauna. Faunal communities are characterized by species associated with a prairie climate and
vegetation. Typical large herbivores and carnivores include coyote, ringtail, and collared
peccary. Smaller herbivores include plains pocket gopher, fulvous harvest mouse, and northern
pygmy mouse. Ocelots were once common, but are now rare. The bison is historically
associated with the Section. Birds are typical of grass and shrublands; residents include many
common species, such as turkey vulture, hairy woodpecker, cardinal, and yellow warbler.
Smith's longspur, a bird of the Arctic tundra, winters here. Amphibians and reptiles typical of
this area include eastern spadefoot toad, Great Plains narrow-mouthed frog, green toad, Texas
toad, Gulf Coast toad, yellow mud turtle, Texas horned lizard, Texas spiny lizard, and Texas
blind snake.
Climate. Precipitation ranges from 30 to 45 inches (750 to 1,150 mm), occurring mainly in
spring from April through May. Temperature averages 63 to 70 F (17 to 21 CT). The growing
season lasts 230 to 280 days.
Disturbance Regimes. Fire and drought have probably been the principal historical sources of
disturbance.
Land Use. Natural vegetation has been changed to agricultural crops on about 75% of the area.
Oak Woods and Prairies (Section 255C)
Geomorphology. This Section is in the Coastal Plains geomorphic province. The predominant
landform on about 80% of the Section consists of irregular plains. Other landforms include
plains with hills and smooth plains. This Section is an elevated sea bottom that has been shaped
by marine and shore-zone processes resulting from repeated episodes of submergence and
emergence of the land from the ocean. Some geomorphic processes currently active throughout
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the area are gentle gradient valley stream erosion, transport and deposition. Elevation ranges
from 650 to 1,310 ft (200 to 400 m). Local relief ranges from 100 to 300 ft.
Photo courtesy Texas Parks and Wildlife Dept. O2003
Lithology and Stratigraphy. Rocks units formed during the Cenozoic Era. Strata are Tertiary
marine sediments consisting of glauconitic, calcarious, fossiliferous strata with lignitic sandy
and argillaceous deposits.
Soil Taxa. Soils are mostly Ustalfs. Paleustalfs and Albaqualfs are on uplands and other areas
with thick sandy surface. Pelluderts, Pellusterts, and Hapludolls are on flood plains and clayey
terraces along major rivers. These soils have a thermic temperature regime, an ustic moisture
regime, and montmorillonitic mineralogy. Soils are deep, medium textured, and generally have
a slowly permeable, clayey subsoil. Moisture may be limiting for plant growth during parts of
the year.
Potential Natural Vegetation. Kuchler classified vegetation as oak-hickory forest, cross timbers
(Querciis-Andropogon), and juniper-oak savanna. The predominant vegetation type is cold-
deciduous, broad-leaved forest. The oak-hickory cover type consists of scarlet, post, and
blackjack oaks, and pignut and mockernut hickories. Forests of elm, pecan, and walnut are in
bottomlands. Little bluestem is the dominant grass.
Fauna. Faunal communities are characterized by species associated with a temperate, subhumid,
forested environment. Common large herbivores and carnivores include coyote, ringtail, ocelot,
and collared peccary. Smaller herbivores include plains pocket gopher, fulvous harvest mouse,
northern pygmy mouse, southern short-tailed shrew, and least shrew. Jaguar and bison are
historically associated with this Section. Birds typical of this Section include many wide-spread
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species, such as eastern bluebird, eastern meadowlark, grasshopper sparrow, mourning dove,
Cooper's hawk, and mockingbird. Amphibians and reptiles include eastern spadefoot toad, Great
Plains narrow-mouthed frog, green toad, yellow mud turtle, Texas horned lizard, Texas spiny
lizard, and Texas blind snake.
Climate. Annual precipitation ranges from 27 to 40 inches (700 to 1,000 mm). Temperature
ranges from 63 to 70 F (17 to 21 CT). The growing season lasts 200 to 260 days.
Surface Water Characteristics. There is a low density of small to medium size perennial streams
and associated rivers, most with moderate volume of water flowing at low velocity. A major
river draining this Section is the Trinity.
Disturbance Regimes. Fire and drought have probably been the principal historical disturbances.
Land Use. Natural vegetation has been converted to agricultural crops on about 75% of the area.
Central Gulf Prairies and Marshes (Section 255D)
Photo courtesy Texas Parks and Wildlife Dept. O2«)«
Geomorphology. This Section is in the Coastal Plains geomorphic province. The predominant
landform consists of a flat, weakly dissected alluvial plain formed by deposition of continental
sediments onto a submerged, shallow continental shelf, which was later exposed by sea level
subsidence. Along the coast, fluvial deposition and shore-zone processes are active in
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developing and maintaining beaches, swamps, and mud flats. Elevation ranges from sea level to
160 ft (0 to 50 m). Local relief ranges from 0 to 100 ft.
Lithology and Stratigraphy. Rock units formed during the Cenozoic Era. Strata consist of
Quaternary marine deposits (non-glacial sand, silt, and clay deposits) of continental origin.
Soil Taxa. Soils are Aquents, Aqualfs, Aquolls, and Aquepts. Psammaquents, Udipsamments,
Fluvaquents, and Salorthids are on barrier islands and long bays. Haplaquolls, Natraqualfs,
Pelluderts, and Pellusterts are on low coastal terraces. Ochraqualfs, Albaqualfs, and Paleudalfs
are found on plains. Haplaquolls, Haplaquents, and Fluvaquents are on coastal flats and flood
plains. These soils have a hyperthermic and thermic temperature regime, an aquic moisture
regime, and montmorillonitic, mixed, or siliceous mineralogy. Soils are fine to coarse textured,
saline, and mostly poorly drained with high water tables.
Potential Natural Vegetation. Kuchler classified vegetation as bluestem-sacahuista prairie and
southern cordgrass prairie. The predominant vegetation form is tall grassland consisting mainly
of bunch grasses. Prairie grasslands dominate areas inland from the coast and consist of little
bluestem, indiangrass, switchgrass, and big bluestem. Occasional areas of live oak are present.
Poorly drained areas along the coast support freshwater and saltwater marsh vegetation of
sedges, rushes, saltgrass, and cordgrass.
Fauna. Large to medium size herbivores and carnivores include coyote, ringtail, hog-nosed
skunk, river otter, ocelot, and collared peccary. Smaller herbivores include swamp rabbit, plains
pocket gopher, fulvous harvest mouse, northern pygmy mouse, and nutria. Bison and jaguar are
historically associated with this Section. Birds of fresh water marshes, lakes, ponds, and rivers
include reddish egret, white-faced egret, white-fronted goose, and olivaceous cormorant. Birds
of these grassland include white-tailed hawk, bronzed cowbird, and Attwater's prairie chicken.
The rare whooping crane winters in this Section at the Aransas National Wildlife Refuge.
Reptiles include American alligator, Gulf coast salt marsh snake, Mediterranean gecko, keeled
earless lizard, Texas horned lizard, Texas spiny lizard, and Texas blind snake. Amphibians
common to this Section include Gulf coast toad and diamondback terrapin.
Climate. Annual precipitation ranges from 25 to 55 inches (620 to 1,400 mm). Temperature
averages 68 to 70 F (20 to 21 C°). The growing season lasts 280 to 320 days.
Surface Water Characteristics. There is a moderate density of small to medium size perennial
streams and a low density of associated rivers, most with moderate volume of water flowing at
very low velocity. The water table is high in many areas, resulting in poor natural drainage and
abundance of wetlands. A poorly defined drainage pattern has developed on very young plains.
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An abundance of palustrine systems are present, having seasonally high water level. This
Section adjoins the Carolinian and Louisianian Marine and Estuarine Provinces.
Disturbance Regimes. Ocean tides have probably been the principal historical disturbance.
Climatic influences include occasional hurricanes.
Land Use. Natural vegetation has been converted to agricultural crops on about 40% of the area.
Great Plains Steppe and Shrub
Redbed Plains (Section 311 A)
Geomorphology. This Section is in the Central Lowlands geomorphic province. Platform uplift
of continental sediments deposited previously into a shallow inland sea, followed by a long
period of erosion; these processes resulted in a moderately to strongly dissected region. About
70% of this Section consists of irregular plains. Other landforms include about equal areas of
plains with low mountains, smooth plains, and tablelands. Elevation ranges from 1,600 to 3,000
ft (500 to 900 m). Local relief in much of the Section ranges from 100 to 300 ft (30 to 90 m).
Smaller areas are present where relief ranges from 30 to 60 ft (10 to 20 m) in tablelands and up
to 1,000 ft (300 m) in low mountains.
Photo courtesy Texas Parks and Wildlife Dept. G2003
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Lithology and Stratigraphy. Rocks formed during the Paleozoic Era. About 80% of the geologic
strata consist of Permian marine deposits (sandstone, shale, and limestone). Other strata include
Quaternary marine deposits and small isolated areas of Lower Cretaceous marine deposits
(limestone).
Soil Taxa. Soils are Ustolls, Ustalfs, and Ochrepts. Most soils are on uplands and include
Argiustolls, Paleustolls, Natrustolls, Haplustalfs, Paleustalfs, and Ustochrepts. Localized areas
of Ustifluvents are on flood plains. These soils have a thermic temperature regime, a ustic
moisture regime, and mixed mineralogy. Most soils are deep, well drained, variable in texture,
and have limited moisture supplies for use by vegetation during part of the growing season.
Potential Natural Vegetation. Kuchler classified vegetation as bluestem-grama prairie, and cross
timbers (Quercus-Andropogon); shinnery (Quercus-Andropogon); and sandsage-bluestem
prairie. The predominant vegetation form is medium-tall grasslands with sparse tree cover.
Grasses consist mainly of sand bluestem, little bluestem, and sand saltbrush.
Fauna. Representative large to medium size herbivores and carnivores include coyote, ringtail,
and ocelot. Small herbivores include eastern cottontail, desert shrew, plains pocket mouse,
Texas kangaroo rat, and prairie vole. Bison and black-footed ferret are historically associated
with this Section. Common birds of thickets and grasslands include the roadrunner, bobwhite,
barn owl, scissor-tailed flycatcher, and common crow. The golden-fronted woodpecker has a
more restricted range. Amphibians common to this environment include Plains spadefoot toad,
Great Plains narrow-mouthed frog, green toad, spotted chorus frog, and yellow-mud turtle.
Typical reptiles include lesser earless lizard, Texas horned lizard, Prairie skink, and Texas blind
snake.
Climate. Precipitation averages 20 to 30 inches (500 to 750 mm): snow averages 20 to 30 inches
(500 to 750 mm) annually. Temperature averages 57 to 64 F (14 to 18 C°). The growing season
lasts 185 to 230 days.
Surface Water Characteristics. The area has a low density of small to medium intermittent
streams and associated rivers, most with a low volume of water flowing at low velocity.
Dendritic drainage pattern has developed without bedrock structural control. Major rivers
include the Washita, Canadian, and Red Rivers.
Disturbance Regimes. Fire and drought have probably been the principal historical disturbances.
Land Use. Natural vegetation has been converted to agricultural crops or pasture on about 90%
of the area.
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Southwest Plateau and Plains Dry Steppe and Shrub
Texas High Plains (Section 315B)
Geomorphology. This Section is in the Great Plains geomorphic province. The predominant
landform consists of a broad, extensive flat plain formed by fluvial sedimentation of continental
erosional products from adjacent mountain ranges, followed by sheet erosion and transport.
These processes resulted in a region of moderate dissection. Elevation ranges from 2,600 to
6,500 ft (800 to 2,000 m). Local relief in most of the Section ranges from 100 to 300 ft,
however, relief in the tablelands ranges from 300 to 500 ft.
Lithology and Stratigraphy. Rocks were formed during the Paleozoic (10%), Mesozoic (10%),
and Cenozoic (80%) Eras. Paleozoic strata consist of Permian marine deposits (sandstone, shale,
and limestone). Mesozoic strata consist of Triassic continental deposits (sandstone). Cenozoic
strata consist of Tertiary Period deposits (poorly consolidated silt, sand, and gravel in varying
proportions).
Soil Taxa. Soils are Ustolls and Ustalfs. Paleustolls, Argiustolls, Paleustalfs, and Haplustalfs are
on uplands. Calciustolls, Haplustolls, and Paleustolls are on ridges and steeper slopes.
Haplustolls occur on young valley floors. Pellusterts are in clayey playa-lake basins.
Calciorthids, Paleorthids, and Torriorthents are on steep slopes in breaks. These soils have a
mesic or thermic temperature regime, a ustic moisture regime, and mixed or carbonatic
mineralogy. Soils are deep, fine to coarse textured, well drained, and have limited soil moisture
for use by vegetation during parts of the growing season.
Potential Natural Vegetation. Kuchler classified vegetation as grama-buffalo grass and shinnery
(Quercus-Andropogon). The predominant vegetation form is short grass communities composed
of bunch grasses with a sparse shrub layer. Species include short grasses (blue gramma, and
buffalograss), sagebrush, mesquite, and yucca.
Fauna. Typical large to medium size herbivores and carnivores include pronghorn, coyote, swift
fox, ringtail, and ocelot. Typical smaller herbivores include desert shrew, desert cottontail,
black-tailed prairie dog, yellow-faced pocket gopher, plains pocket mouse, silky pocket mouse,
hispid pocket mouse, and white-throated woodrat. Bison are historically associated with this
Section. Birds of grasslands include many species that typically occur over a wide area, such as
roadrunner, house finch, yellow warbler, willow flycatcher, cedar waxwing, western kingbird,
and golden eagle. The lesser prairie chicken, found here, is restricted to the more arid
grasslands. Amphibians found in this Section include plains spadefoot toad, Couche's spadefoot
toad, western spadefoot toad, plains leopard frog, Great Plains toad, green toad, red spotted toad,
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spotted chorus frog, and yellow-mud turtle. Reptiles include species such as Texas horned
lizard, round-tailed horned lizard, Great Plains skink, Texas blind snake, and plains black-
headed snake.
Photo courtesy Texas Parks and Wildlife Dept. O2003
Climate. Precipitation averages 14 to 18 inches (350 to 450 mm), occurring mainly in the spring
and fall. Temperature averages 55 to 63 F (13 to 17 CT). The growing season lasts 130 to 220
days.
Surface Water Characteristics. There is a low density of small intermittent streams and few
associated rivers, all with low volume of water flowing at low velocity. A shallow dendritic
drainage pattern has developed. Major rivers include the Canadian and Red. The Canadian
River, in north Texas, is deeply incised into the Great Plains plateau and has developed a broad
area (up to 50 miles wide) of complex topography locally known as "The Breaks." Playa lakes
are common in the western part of this Section.
Disturbance Regimes. Fire and drought have probably been the principal historical disturbances.
Land Use. Natural vegetation has been converted to agricultural crops or pasture on about 90%
of the area.
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Rolling Plains (Section 315C)
Photo courtesy Texas Parks and Wildlife Dept. O2003
Geomorphology. This Section is in the Central Lowlands geomorphic province. Landforms
originated from platform uplift of continental sediments deposited previously into a shallow
inland sea, followed by a long period of erosion. These processes resulted in a moderately
dissected landscape. About 80% of this Section is equally divided between irregular plains and
tablelands. Smaller areas of smooth plains and plains with hills are also present. Elevation
ranges from 1,640 to 2,950 ft (500 to 900 m). Local relief in most of the Section ranges from
100 to 300 ft. Smaller areas are present where local relief ranges from 300 to 500 ft.
Lithology and Stratigraphy. Rocks were formed during the Paleozoic and Mesozoic Eras.
Geologic strata consist of about equal amounts of Permian marine deposits and Triassic
continental deposits (sandstone). A small area of Permian continental deposits (sandstone, shale,
and limestone) is also present.
Soil Taxa. Soils are Ustolls, Ustalfs, and Ochrepts. Most soils are on uplands and include
Argiustolls, Paleustolls, and Natrustolls, Haplustalfs, Paleustalfs, and Ustochrepts. Localized
areas of Ustifluvents are on flood plains. These soils have a thermic temperature regime, a ustic
moisture regime, and mixed mineralogy. Most soils are deep, well drained, variable in texture,
and have limited moisture supplies for use by vegetation during part of the growing season.
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Potential Natural Vegetation. Kuchler classified vegetation as mesquite-buffalo grass. The
predominant vegetation form is medium-tall grassland with a sparse shrub cover. The vegetative
community consists of sand and little bluestems and sagebrush.
Fauna. The faunal community consists of species suited to a semi-arid environment. Large to
medium-size mammals include coyote, ringtail, ocelot, and collared peccary. Typical smaller
herbivores include desert cottontail, hispid pocket mouse, Texas kangaroo rat, Texas mouse,
desert shrew, and rock squirrel. Bison and black-footed ferret are historically associated with
this Section. Domesticated cattle are the most common large herbivore. Birds of thickets and
grasslands include black-capped vireo, Harris' sparrow, scaled quail, golden-fronted
woodpecker, and pyrrhuloxia. Amphibians include Couche's spadefoot toad, Great Plains
narrow-mouthed frog, green toad, red-spotted toad, and Texas toad. The spotted chorus frog,
yellow-mud turtle, and Texas map turtle are in wetter areas. Common reptiles include lesser
earless lizard, crevice spiny lizard, Texas spotted whiptail, Great Plains skink, prairie skink,
four-lined skink, western hook-nosed snake, Harter's water snake, and plains black-headed
snake.
Climate. Precipitation averages 18 to 24 inches (450 to 600 mm). Temperature averages 57 to
64 F (14 to 18 CT). The growing season lasts 185 to 230 days.
Surface Water Characteristics. There is a low density of small intermittent streams and few
associated rivers, all with low volume of water flowing at low velocity. A dendritic drainage
pattern has developed. Major rivers include the Colorado and Brazos.
Disturbance Regimes. Fire and drought have probably been the principal historical disturbances.
Land Use. Natural vegetation has been converted to agricultural crops or pasture on about 90%
of the area.
Edwards Plateau (Section 315D)
Geomorphology. This Section is in the Great Plains geomorphic province. The predominant
landform consists of a broad, extensive flat plain formed by fluvial sedimentation of continental
erosional products from adjacent mountain ranges, followed by sheet erosion and transport; these
processes resulted in a region of moderate dissection. About 90% of this Section consists of
landforms equally divided between smooth plains and tablelands having moderate relief. Also
included are smaller areas of open high hills, high hills, and plains with hills. Elevation ranges
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from 650 to 4,000 ft (200 to 1,200 m). Local relief in most of the Section ranges from 100 to
300 ft (30 to 90 m). In a small area of hills, relief ranges from 300 to 500 ft (90 to 150 m).
Photo courtesy Texas Parks and Wildlife Dept. O2003
Lithology and Stratigraphy. Rock units in this Section were formed during the Precambrian
(10%), Paleozoic (30%), and Mesozoic (60%) Eras. Precambrian strata consist of metamorphic
rocks of paragneiss and schist structures and plutonic and intrusive rocks of granitic
composition. Paleozoic strata consist of a mixture of Cambrian (carbonates) and lower
Ordovician marine deposits (carbonates). Mesozoic strata consist of Cretaceous marine deposits
(limestone and sandstone).
Soil Taxa. Soils are mostly Ustolls. Calciustolls are on limestone hills and plateaus.
Chromusterts are on outwash plains and broad plateaus. Ustochrepts are on marl and chalk hills.
Haplustolls are on stream deposits of valley floors. These soils have a thermic temperature
regime, a ustic moisture regime, and carbonatic or montmorillonitic mineralogy. Soils are
generally shallow, fine textured, and have limited soil moisture for use by vegetation during
parts of the growing season.
Potential Natural Vegetation. Kuchler classified vegetation as juniper-oak savanna and
mesquite-acacia-savanna. The predominant vegetation form is mid to short grasslands and
evergreen scale-leaved woodlands with a sparse cover of drought-deciduous shrubs. A mixture
of species may occur, including blackjack oak, red cedar, mesquite, live oak, and species of mid
and short grass grasslands.
Fauna. Common large to medium size herbivores and carnivores include coyote, ringtail, coati,
hog-nosed skunk, ocelot, and collared peccary. Smaller herbivores include Mexican ground
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squirrel, white-ankled mouse, and prairie vole. Bison are historically associated with this
Section. Domesticated cattle are the most common large herbivores. Birds of thickets typically
found here include scaled quail, golden-fronted woodpecker, golden-cheeked warbler,
pyrrhuloxia, and long-billed thrasher. Amphibians include Couche's spadefoot toad, Rio Grande
leopard frog, Great Plains narrow-mouthed frog, green toad, Texas toad, spotted chorus frog,
barking frog, cliff chirping frog, and Texas map turtle. A number of salamanders in this Section
have a very restricted range: San Marcas, Texas, Cormal blind, Valdina Farms, and Texas blind.
Typical reptiles include Mediterranean gecko, spot-tailed earless lizard, keeled earless lizard,
Texas spiny lizard, Great Plains skink, and four-lined skink.
Climate. Annual precipitation ranges from 15 to 30 inches (375 to 750 mm). Average
temperature is 64 to 68 F (18 to 20 CT). The growing season lasts 230 to 270 days.
Surface Water Characteristics. A low density of small intermittent and occasional perennial
streams occurs here. All generally have a low volume of water flowing at low velocity, except
along the plateau escarpment, where flow rates can be high. A dendritic drainage pattern has
developed. Major rivers include the Brazos and Colorado.
Disturbance Regimes. Fire and drought have probably been the principal historical disturbances.
Land Use. Natural vegetation has been changed to agricultural crops or pasture on about 90% of
the area.
Rio Grande Plain (Section 315E)
Geomorphology. This Section is in the Coastal Plains geomorphic province. The predominant
landform in this Section is a flat, weakly dissected alluvial plain formed by deposition of
continental sediments onto submerged, shallow continental shelf, which was later exposed by
sea level subsidence. Elevation ranges from 80 to 1,000 ft (25 to 300 m). Local relief in most of
the Section ranges from 100 to 300 ft (30 to 90 m).
Lithology and Stratigraphy. Rocks formed during the Cenozoic Era. These strata consist of
Tertiary marine deposits (glauconitic, calcareous, fossiliferous layers with lignitic sandy and
argillaceous deposits).
Soil Taxa. Soils are Usterts, Torrerts, and Ustalfs. Pellusterts are on plains over clayey marine
sediments. Paleustalfs are on eolian plains. Torrerts, Haplustolls, Calciustolls, Paleustalfs, and
Haplustalfs are on plains. Calciustolls and Calciorthids are on plains over marine sediments.
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Soils have a hyperthermic temperature regime, a ustic or aridic moisture regime, and mixed
mineralogy. Soils are mostly deep, fine to coarse textured, well drained, and have limited soil
moisture for use by vegetation during the growing season.
Potential Natural Vegetation. Kuchler classified vegetation as mesquite-acacia-savanna and
ceniza shrub. The predominant vegetation form is short grassland with a sparse cover of drought
deciduous shrubs. Species include mesquite, cactus, and tall and mid grasses. Live oaks and
cottonwoods may be present along stream banks.
Photo courtesy Texas Parks and Wildlife Dept. O2003
Fauna. Typical large to medium size herbivores and carnivores include coyote, ringtail, hog-
nosed skunk, and ocelot. Smaller herbivores include Mexican ground squirrel, Texas pocket
gopher, and southern plains woodrat. Bats typical of this Section include the ghost-faced and
Sanborn's long-nosed. Bison, jaguar, and jaguarundi are historically associated with this
Section. This Section and adjacent 315E form the northern range of a number of birds common
to Mexico and South America. Typical birds include chachalaca, green kingfisher, pauraque, elf
owl, white-winged dove, red-billed pigeon, black-headed oriole, kiskadee flycatcher, yellow-
green vireo, Lichtenstein's oriole, tropical kingbird, beardless flycatcher, buff-bellied
hummingbird, green jay, long-billed thrasher, and white-collared seedeater. Amphibians include
Mexican burrowing toad, Rio Grande leopard frog, sheep frog, giant toad, spotted chorus frog,
Mexican tree frog, Rio Grande chirping frog, and Berlandier's tortoise. Reptiles include Texas
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banded gecko, reticulate collared lizard, spot-tailed earless lizard, keeled earless lizard, blue
spring lizard, mesquite lizard, rose-bellied lizard, Laredo striped whiptail, black-striped snake,
indigo snake, speckled racer, and cat-eyed snake.
Climate. Precipitation ranges from 17 to 30 inches (420 to 750 mm), decreasing from east to
west and occurring mostly during May and June. Temperature averages 70 to 72 F (21 to 22 C°).
The growing season lasts 260 to 310 days.
Surface Water Characteristics. A sparse density of small to medium intermittent streams is
present in a dendritic drainage pattern. Major rivers include the Rio Grande and Nueces.
Disturbance Regimes. Drought has probably been the principal historical disturbance.
Land Use. Natural vegetation has been converted to dry-land pasture for cattle grazing on about
90% of the area.
Southern Gulf Prairies and Marshes (Section 315F)
Photo courtesy Texas Parks and Wildlife Dept. O2003
Geomorphology. This Section is in the Coastal Plains geomorphic province. The predominant
landform consists of a flat, weakly dissected alluvial plain formed by deposition of continental
sediments onto a submerged, shallow continental shelf, which was later exposed by sea level
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subsidence. Along the coast, fluvial deposition and shore-zone processes are active in
developing and maintaining beaches, swamps, and mud flats. Elevation ranges from sea level to
160 ft (0 to 50 m). Local relief ranges from 0 to 50 ft (0 to 18 m).
Lithology and Stratigraphy. Rock units formed during the Cenozoic Era. These strata consist of
Quaternary marine deposits of non-glacial sand, silt, and clay.
Soil Taxa. Soils are Aquents, Aqualfs, Aquolls, and Aquepts. Psammaquents, Udipsamments,
Fluvaquents, and Salorthids are on barrier islands and long bays. Haplaquolls, Natraqualfs,
Pelluderts, and Pellusterts are on low coastal terraces. Ochraqualfs, Albaqualfs, and Paleudalfs
are found on plains. Haplaquolls, Haplaquents, and Fluvaquents are on coastal flats and flood
plains. These soils have a hyperthermic and thermic temperature regime, an aquic moisture
regime, and montmorillonitic, mixed, or siliceous mineralogy. Soils are fine to coarse textured,
saline, and mostly poorly drained with high water tables.
Potential Natural Vegetation. Kuchler classified vegetation as bluestem-sacahuista prairie and
southern cordgrass prairie. The predominant vegetation form is tall grassland with little tree
cover. Grasslands dominate areas inland from the coast and consist of little bluestem,
indiangrass, switchgrass, and big bluestem. Occasional areas of live oak are present. Poorly
drained areas along the coast support freshwater and saltwater marsh vegetation of sedges,
rushes, saltgrass, and cordgrass.
Fauna. The faunal communities typically include coyote, ringtail, hog-nosed skunk, ocelot, and
collared peccary. Smaller mammals include Mexican ground squirrel, Texas pocket mouse,
northern pygmy mouse, and southern Plains woodrat. Birds of freshwater marshes, lakes, ponds,
and rivers include reddish egret, white-faced ibis, black-billed whistling duck, white-fronted
goose, and olivaceous cormorant. Reptiles and amphibians include eastern spadefoot toad, Gulf
coast toad, American alligator, diamondback terrapin, spiny-tailed iguana, Texas horned lizard,
Texas spotted whiptail, and indigo snake.
Climate. Precipitation ranges from 25 to 55 inches (620 to 1,400 mm). Temperature averages
68 to 70 F (20 to 21 (T). The growing season lasts 280 to 320 days.
Surface Water Characteristics. A low density of small to medium perennial streams is present in
this Section. The water table is high in many areas, resulting in poor natural drainage and
abundance of wetlands. A poorly defined drainage pattern has developed on very young alluvial
plains. There is an abundance of palustrine systems with seasonally high water levels. This
Section adjoins the West Indian Marine and Estuarine Provinces.
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Disturbance Regimes. Ocean tides and grazing have probably been the principal historical
disturbance. Climatic influences include occasional hurricanes.
Land Use. Natural vegetation has been changed for agricultural crops on about 40% of the area.
Arizona-New Mexico Mountains Semi-Desert - Open Woodland - Coniferous Forest -
Alpine Meadow
Sacramento-Manzano Mountain (Section M313B)
Geomorphology. This Section is in the Basin and Range physiographic province; it is located in
central and south-central New Mexico. Major landforms are mountains, hills, plains, and scarps.
Major landform features are the Sacramento, Manzano and Sandia Mountains and the Canadian
Escarpment. Elevation ranges from 6,000 to 11,000 ft (2,130 to 3,690 m).
Photo courtesy Texas Parks and Wildlife Dept. O2003
Lithology and Stratigraphy. There are Paleozoic sedimentary and Cenozoic aged igneous rocks
and a few metamorphic rocks.
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Soil Taxa. Soils include Eutroboralfs, Glossoboralfs, Dystrochrepts, Ustochrepts, Argiustolls,
Calciustolls, Haplustolls, and Ustorthents with mesic and frigid temperature regimes and ustic
and udic soil moisture regimes. A few Cryoboralfs and Cryochrepts occur with cryic soil
temperature regimes and udic soil moisture regimes.
Potential Natural Vegetation. Vegetation consists of ponderosa pine in frigid soil temperature
regimes and ustic and udic soil moisture regimes, Douglas-Fir in frigid-udic regimes, pinyon-
juniper in mesic-ustic regimes, and Engelmann spruce, and subalpine fir in cryic-udic regimes.
A few areas support grey oak at the lowest elevations.
Climate. Precipitation ranges from 12 to 35 inches (305 to 900 mm), with less than half of the
precipitation falling during the winter. Temperature averages 40 to 57 F (4 to 8 CT); winter
temperatures vary throughout this Section. The growing season lasts less than 70 to 170 days.
Surface Water Characteristics. This Section supplies much of the water to the Rio Grande and
Pecos Valley basins. Several streams are perennial.
Disturbance Regimes. Natural fire regime averages 3 to 10 years of frequency in ponderosa pine
forests. Much of this area is covered with timber, with some areas of commercial quality.
Another use of land is as range.
Cultural Ecology. The earliest human occupation of the Sacramento-Manzano Mountain Section
was characterized by an emphasis on big game hunting supplemented with gathering wild plant
foods. Evidence for these activities is primarily restricted to the lower elevations and the base of
the mountains. Around 6000 B.C., a gradual climate change from cooler and wetter to drier
conditions resulted in a change of subsistence patterns. Highly mobile populations hunted and
gathered a variety of resources throughout the region. The pinon-juniper zone was intensely
exploited for both hunting and gathering. The mixed conifer forests were utilized to some extent
for hunting and religious purposes, but the climate and scarcity of resources resulted in only
sporadic use. As agriculture became important during the past 2000 years, most of the
inhabitants became more sedentary and populations increased. Villages tended to be located
close to water in the pinon-juniper woodland and lower alluvial fans at the base of the
mountains. Athabascan groups entered the area sometime before the 1600's, utilizing many of
the same resources; by the mid 1700's, Comanches occupied the plains immediately to the east.
Today, Native Americans continue to use the mountains for gathering and ceremonial purposes.
The earliest historic settlement began in the late 1500's with the Spaniards. A few
villages were established in the foothills of the Manzanos, Sandias, and near the headwaters of
the Canadian and Pecos Rivers, but the Apaches kept most European settlers out of the
Sacramentos and mountain ranges to the south. These settlers concentrated on the pinon-juniper
woodlands and grasslands for hunting, fuel wood gathering, post cutting, and small subsistence
farming. Beginning in the late 1800's, discoveries of gold and an increase in European
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settlement throughout the mountains resulted in more intensive use of the higher elevations for
mining, logging, and ranching activities. Most of the homesteads and villages were located in
the larger valleys or on the eastern slopes of the mountains near permanent water sources. By
the turn of the century, logging dominated the activities in the mixed conifer zone, with ranching
still playing an important role throughout the mountains. Currently, the area continues to consist
primarily of small rural communities, with logging, fuel wood gathering, ranching, hunting, and
recreation as the primary subsistence base. Anglo, Hispanic, and Mescalero Apache cultures are
present. Recreational use has increased dramatically over the past few decades, particularly near
the larger cities.
Chihuahuan Semi-Desert
Basin and Range (Section 321A)
Photo courtesy Texas Parks and Wildlife Dept. O2003
Geomorphology. This area, which is in the Basin and Range physiographic province, is located
in southeast Arizona and southwest and central New Mexico. Relatively recent episodes of
continental rifting, volcanism, erosion, and sedimentation have dominated this Section.
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Oligocene faulting created the Rio Grande rift in New Mexico and west Texas and initiated
volcanism. Subsequent Miocene composite volcanoes emitted silicic lava and ash. Along with
Pliocene and Pliestocene mass wasting and cyclic erosion events, and associated with glacial
cycles farther north, this combination of processes gradually filled the basins with deep
sediments from adjacent mountain ranges. Current erosion cycles dissect these deposits and
continue to modify the rift valley through transport and deposition processes. Various landforms
comprise about equal areas: (1) plains with low mountains consisting of 50 to 80% of gently
sloping area and local relief of 1,000 to 3,000 ft; (2) plains with high hills where relief is 1,000
to 3,000 ft; (3) open high hills with relief of 500 to 1,000 ft; and (4) tablelands with moderate
relief averaging 100 to 300 ft. Elevation ranges from 2,600 to 5,500 ft (800 to 1676 m).
Lithology and Stratigraphy. Geologic strata consist of an undifferentiated mixture of Quaternary
marine deposits, Miocene volcanic rocks, lower Tertiary volcanic rocks, and Lower Cretaceous
marine deposits; Permian marine deposits of Ochoan and Guadalupian series; Paleocene
continental deposits; Upper Cretaceous marine deposits; Precambrian plutonic and intrusive
granitic rocks; Quarternary volcanic rocks; Permian continental deposits of Wolcampian age,
and Miocene felsic volcanic rocks; upper Paleozoic marine deposits; Precambrian sedimentary
rocks of Pahrump and Unkar groups; Precambrian Mazatal quartzite, Yavapai series, pinal
schist, and metavolcanic formations.
Soil Taxa. Types are mostly Torriorthents with Calciorthids, Haplargids, and some Alfisols
(10%) and Mollisols (10%) with a thermic temperature regime, an aridic moisture regime, and
mixed or carbonatic mineralogy.
Potential Natural Vegetation. Kuchler mapped vegetation as trans-Pecos shrub savanna
(Flourensia-Larreci); grama-tobosa desert grasslands; oak-juniper woodland; and mesquite-
tarbush desert scrub.
Climate. Precipitation ranges from 8 to 13 inches (200 to 320 mm): it occurs mostly during July
and August. Temperature ranges from 55 to 70 F (13 to 20 CT) and winters are mild. The
growing season lasts 200 to 240 days.
Surface Water Characteristics. There is a low density of intermittent streams and very few
associated rivers, most of which originate in distant mountainous areas. Flow rates are low to
moderate, except during periods of heavy rain, when large amounts of surface runoff can occur.
Dendritic drainage pattern has developed on dissected mountain slopes, largely without bedrock
structural control. Playa lakes are common following periods of rains, but are ephemeral in the
hot, dry climate prevalent in this Section.
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Disturbance Regimes. Drought has probably been the principal historical source of disturbance.
Land Use. Land use includes range for cattle grazing on about 90% of the area.
Cultural Ecology. The Basin and Range Section is a physiographically diverse area
characterized by expansive playas and open grassland basins cut by steep, rugged mountain,
mesa, and canyon terrain. Humans have been utilizing the area for 8,000 to 10,000 years,
although evidence of occupation prior to 7,000 B.C. remains scarce and scattered. Paleo-Indian
materials are especially prevalent, however, from the foothills of the Tularosa Mountains. The
area was widely utilized by Cochise and Oshara Tradition Archaic populations between 7,000
B.C. and 200 A.D. Site distribution points to a highly mobile hunting and gathering nomadic
subsistence pattern initially, followed by use of increasingly smaller areas and a seasonal cycle
of upland and lowland exploitation. Puebloan use and occupation were most prevalent between
200 and 1150 A.D. in the south and 200 and 1400 A.D. in the north. Southern basin, range, and
mountain areas supported the Mogollon culture, while more northern mountain areas also
included the southern fringe of the Anasazi tradition. Puebloan settlement reflected gradual
movement toward major drainages and waterways over time. Basin and range deserts were
widely used for wild plant procurement, agriculture, and settlement.
References to the Apache appear in 16th century Spanish documents and later historic
accounts. Spanish expeditions passed through the area, but major settlements were restricted to
the Rio Grande and the area east of the Mogollon and Tularosa Mountains. Livestock ranching
and mining gained prominence in the 1800's. Gold, silver, copper, and turquoise were mined in
the Mogollon, Burro, and Black Range Mountains of New Mexico. Introduction of the railroad
in the 1800's witnessed an influx of European settlement along the Rio Grande, the southern
Burro Mountains (Deming, Lordsburg, and Silver City, New Mexico) and more northern reaches
of the Mogollon Mountains. In more northern, remote mountain areas, small ranching, mining,
and timber-related settlements were established along major rivers and ephemeral drainages.
Ranching and tourism flourish in the area today, and both Anglo and Hispanic cultures influence
contemporary life.
Stockton Plateau (Section 321B)
Geomorphology. This Section is in the Great Plains geomorphic province. The predominant
landform consists of open high hills with smaller areas of tablelands. These landform were
formed by fluvial sedimentation of continental erosional products from adjacent mountain
ranges, which was followed by sheet erosion and transport. These processes resulted in a region
of shallow dissection. Elevation ranges from 2,600 to 4,500 ft (800 to 1,300 m). Local relief in
most of the Section ranges from 500 to 1,000 ft. Relief in a small area of tablelands ranges from
300 to 500 ft.
169
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-:-^rr;?swsiiiBS^jgjrTt ,.„n,
^t.ta:.%:^:~ ~'^i33ss:---.aap«p»» --'•*;!-»'-.»; I >*•••-
Photo courtesy Texas Parks and Wildlife Dept. O2003
Lithology and Stratigraphy. Rocks were formed during Paleozoic (35%), Mesozoic (40%), and
Cenozoic (25%) Eras. Paleozoic strata consist of Pennsylvanian marine deposits. Mesozoic
strata consist of nondifferentiated mixture of Lower and Upper Cretaceous marine deposits
(limestone, and sandstone). Cenozoic strata consist of lower Tertiary volcanic rocks of high
alkalic content.
Soil Taxa. Soils are Argids and Orthids. Haplargids, Paleargids, and Calciorthids are on
uplands, piedmont plains, and dissected terraces. Calciorthids, Ustolls, and Torriorthents are on
uplands with shallow depths to bedrock. Paleorthids are on mesas and terraces. Gypsiorthids
are in closed basins. Natragids and Torrerts are on basin floors. Torrifluvents are on flood
plains and Torripsamments are on sandy uplands. These soils have a thermic temperature
regime, aridic moisture regime, and mixed or carbonatic mineralogy. Soils are well drained,
shallow to deep, and medium textured. Soil moisture is limited for use by vegetation during
most of the growing season.
Potential Natural Vegetation. Kuchler classified vegetation as trans-Pecos shrub savanna
(Flourensia-Larrea); with juniper and red cedar woodlands. The predominant vegetation form is
short to mid height grasslands with sparse cover of drought-deciduous and scale-leaved shrubs
and small trees. Species include desert shrubs in association with short to mid height grasses and
oak savannas.
Fauna. Typical large to medium size herbivores and carnivores include pronghorn, coyote, swift
fox, ringtail, hooded skunk, ocelot, and collared peccary. Smaller herbivores include desert
shrew, desert cottontail, Mexican ground squirrel, yellow-faced pocket gopher, Nelson's pocket
mouse, and Merriam's kangaroo rat. Several bats, western mastiff and yuma myotis, are present
here. Birds of grasslands include bronzed cowbird, Baird's sparrow, and white-necked raven.
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Birds of thickets include black-capped vireo, scaled quail, Harris' hawk, Inca dove, cave
swallow, golden-fronted woodpecker, and pyrrhuloxia. Amphibians include Couche's spadefoot
toad, western spadefoot toad, Rio Grande leopard frog, Great Plains toad, red-spotted toad,
spotted chirping frog, and Mexican mud turtle. Reptiles include Texas banded gecko, Big Bend
gecko, desert spring lizard, canyon lizard, crevice spiny lizard, gray checkered whiptail, little
striped whiptail, plateau spotted whiptail, checkered whiptail, Texas-Pecos rat snake, gray-
banded kingsnake, Big Bend patch-nosed snake, Mexican black-nosed snake, Big Bend black-
headed snake, rock rattlesnake, and black-tailed rattlesnake.
Climate. Precipitation ranges from 8 to 13 inches (200 to 320 mm). Temperature ranges from
55 to 64 F (13 to 18 (T). The growing season lasts 200 to 240 days.
Surface Water Characteristics. This section has a low density of intermittent streams that
originate in nearby mountainous areas and flow mainly following rains. Major river systems
include the Rio Grande and Big Canyon. Flow rates are low except during periods of heavy rain,
when large amounts of surface runoff can occur. Dendritic drainage pattern has developed.
Playa-type lakes are present following rains but quickly dry up, leaving high salt concentrations.
Disturbance Regimes. This section is part of the Chihuahuan Desert and drought has been the
principal disturbance.
Land Use. Cattle grazing occurs on about 90% of the area.
Great Plains-Palouse Dry Steppe
Southern High Plains (Section 331B)
Geomorphology. This Section is in the Great Plains geomorphic province. The predominant
landform is a broad, extensive flat plain formed by fluvial sedimentation of continental erosional
products from adjacent mountain ranges, followed by sheet erosion and transport. These
processes resulted in a region of moderate dissection. Landforms consist mostly of smooth
plains with smaller areas of tablelands. Elevation ranges from 2,600 to 4,000 ft (800 to 1,200
m). Local relief ranges mainly from 100 to 300 ft (90 m). A small area of tablelands is present
where relief ranges from 300 to 500 ft (90 to 150 m).
171
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Lithology and Stratigraphy. Rocks were formed during the Paleozoic (20%), Mesozoic (20%),
and Cenozoic (60%) Eras. Paleozoic strata consist of Permian marine deposits (shale and
limestone). Mesozoic strata consists of Upper Cretaceous marine deposits (limestone and
sandstone). Cenozoic strata consists of Quaternary continental deposits (poorly consolidated silt,
sand, and gravel in varying proportions) and other localized marine deposits.
Soil Taxa. Soils are Ustolls and Ustalfs. Paleustolls, Argiustolls, Paleustalfs, and Haplustalfs
are on uplands. Calciustolls, Haplustolls, and Paleustolls are on ridges and steeper slopes.
Haplustolls occur on young valley floors. Pellusterts are in clayey playa lake basins.
Calciorthids, Paleorthids, and Torriorthents are steep slopes in breaks. These soils have a mesic
or thermic temperature regime, an ustic moisture regime, and mixed or carbonatic mineralogy.
Soils are deep, fine to coarse textured, well drained, and have limited soil moisture for use by
vegetation during parts of the growing season.
Potential Natural Vegetation. Kuchler classified vegetation as sandsage-bluestem prairie and
bluestem-grama prairie. The predominant vegetation form is short to mid-height grasslands.
Species composition includes bluegrama, buffalograss, hairy grama, and little bluestem.
Fauna. Large to medium size herbivores and carnivores typical of this Section include
pronghorn, coyote, and ringtail. Smaller herbivores include desert shrew, black-tailed prairie
dog, Plains pocket mouse, silky pocket mouse, and hispid pocket mouse. Bison and black-footed
ferret are historically associated with this Section. Birds of grasslands include lesser prairie
chicken, Swainson's hawk, and burrowing owl. Typical reptiles and amphibians include Great
Plains toad, red spotted toad, lesser earless lizard, round-tailed horned lizard, Great Plains skink,
and Plains black-headed snake.
Climate. Annual precipitation averages 16 to 20 inches (400 to 520 mm). Between 16 to 35 in
(400 to 900 mm) of snow occurs. Temperature ranges from 50 to 57 F (10 to 14 C°). The
growing season lasts 140 to 185 days.
Surface Water Characteristics. There is a low density of small intermittent streams with low
volume of water flowing at low velocity. A dendritic drainage pattern has developed on a
weakly dissected plateau, largely without bedrock structural control. Major rivers include the
Cimarron and North Canadian.
Land Use. Natural vegetation has been converted to agricultural crops and range for cattle
grazing on about 90% of the area.
172
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APPENDIX B
Individual Sub-Layer Maps
173
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Table of Contents
Chapter Page
Diversity layer 176
Rarity layer 177
Sustainabilitv layer 179
List of Figures
Figure Page
Figure Bl. Map of diversity sub-layer: appropriateness of land cover. This map
is used to produce the map of the diversity layer (Figure 5) 181
Figure B2. Map of diversity sub-layer: contiguous size of undeveloped land.
This map is used to produce the map of the diversity layer (Figure 5) 182
Figure B3. Map of diversity sub-layer: Shannon land cover diversity index.
This map is used to produce the map of the diversity layer (Figure 5) 183
Figure B4. Map of diversity sub-layer: ecologically significant stream segments.
This map is used to produce the map of the diversity layer (Figure 5) 184
Figure B5. Map of rarity sub-layer: vegetation rarity. This map is
used to produce the map of the rarity layer (Figure 6) 185
Figure B6. Map of rarity sub-layer: natural heritage rank. This map
is used to produce the map of the rarity layer (Figure 6) 186
Figure B7. Map of rarity sub-layer: taxonomic richness. This map
is used to produce the map of the rarity layer (Figure 6) 187
Figure B8. Map of rarity sub-layer: rare species richness. This map is
used to produce the map of the rarity layer (Figure 6) 188
174
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Figure B9. Map of sustainability sub-layer: contiguous land cover type. This
map is used to produce the map of the sustainability layer (Figure 6) 189
Figure BIO. Map of sustainability sub-layer: regularity of ecosystem boundary. This
map is used to produce the map of the sustainability layer (Figure 7) 190
Figure Bll. Map of sustainability sub-layer: appropriateness of land cover. This
map is used to produce the map of the sustainability layer (Figure 7) 191
FigureB 12. Map of sustainability sub-layer: waterway obstruction. This map
is used to produce the map of the sustainability layer (Figure 7) 192
FigureB 13. Map of sustainability sub-layer: road density. This map is
used to produce the map of the sustainability layer (Figure 7) 193
FigureB 14. Map of sustainability sub-layer: airport noise. This map is
used to produce the map of the sustainability layer (Figure 7) 194
FigureB 15. Map of sustainability sub-layer: Superfund National Priority
List and state Superfund Sites. This map is used to produce the map
of the sustainability layer (Figure 7) 195
FigureB 16. Map of sustainability sub-layer: water quality. This map is
used to produce the map of the sustainability layer (Figure 7) 196
Figure B17. Map of sustainability sub-layer: air quality. This map is
used to produce the map of the sustainability layer (Figure 7) 197
FigureB 18. Map of sustainability sub-layer: RCRA TSD, corrective action and
state VCP sites. This map is used to produce the map of the
sustainability layer (Figure 7) 198
FigureB 19. Map of sustainability sub-layer: urban/agriculture disturbance. This
map is used to produce the map of the sustainability layer (Figure 7) 199
175
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The figures displayed in this appendix represent the individual sub-layers that constitute
the main layers and ultimately the composite. The data for each sub-layer was calculated at the
ecoregion level. However, for GIS technical reasons and presentation purposes, the legends of
Appendix B figures reflect statewide ranking (i.e., the red shaded areas indicate the particular
range of values statewide). This is different from the report text where sub-layers were
combined and the results presented by ecoregion (i.e., the red areas indicate the 1%, 10%, etc. in
that particular ecoregion). The data is the same (i.e., all calculated by ecoregion), only the
presentation legend and scaling is different. On some figures, there were enough cells with a
score of 100 that there was no way to separate the top 1% and top 10% (the top 1% of cells
scored 100 and the top 10% of cells also scored 100), for example, road density (Figure B13).
Diversity layer
The statewide trend shows a higher level of appropriate vegetation in Rio Grande Plain,
Stockton Plateau, Chihuahuan Desert Basin and Range, the southern part of Rolling Plains
ecoregion. The Mid Coastal Plains Western Section, Oak Woods and Prairies, and Coastal
Prairies and Marshes ecoregions show more disturbance in terms of what type of vegetation
cover would exist without human influence (Figure Bl). The amount of potential natural
vegetation is also related to the amount of human disturbance, i.e. issues concerning
sustainability of the area (see Sustainability section below).
There are many areas of larger tracts of undeveloped land including Chihuahuan Desert
Basin and Range and Stockton Plateau ecoregions, portions of the Rolling Plains ecoregion, Rio
Grande Plain ecoregion, northern Texas High Plains ecoregion (around the Canadian River),
176
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southern portion of the Edwards Plateau, Mid Coastal Plains Western Section, and Coastal
Plains and Flatwoods Western Gulf Section (Figure B2).
The Shannon land diversity index map shows higher levels in the Blackland Prairie, Oak
Woods and Prairies, Mid Coastal Plains Western Section, and Coastal Plains and Flatwoods
Western Gulf Section ecoregions which might seem contradictory to the previous measure of
contiguous land cover. Figure B3 shows that there are more, different types of undeveloped land
cover in the eastern part of the state, covering several ecoregions and not as many undeveloped
land cover types (nor as well dispersed), in the northern and western portions of the state. For
various ecological reasons, the central and eastern portions of the state maintain this vegetative
stratification. The amount of water adds another dimension of diversity, in that wetland areas
are present. Fewer wetland areas or vegetative stratification exists in the western and northern
parts of Texas.
Ecologically significant stream segments (Figure B4) are ecologically unique areas
determined by TPWD based on biological function, hydrologic function, riparian conservation
areas, high water quality (including aquatic life and aesthetic value), and threatened or
endangered species. Significant stream segments are fairly well distributed throughout the
central and eastern portions of the state.
Rarity layer
Oak Woods and Prairies, and Central Gulf Prairies and Marshes ecoregions show the
highest levels of vegetation rarity. The pattern of these rare areas is indicative of riparian areas
(Figure B5). This is particularly evident in the Mid Coastal Plains Western Section, and the
177
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northern portion of the Oak Woods and Prairies ecoregion. In addition, the Central Gulf Prairies
and Marshes ecoregion shows a high density of rare vegetation types.
The Rolling Plains, Cross Timbers and Prairie and Texas High Plains ecoregions have
species with lower natural heritage ranks (Figure B6). Most of the areas that have high natural
heritage ranks are located Chihuahuan Desert Basin and Range ecoregion, Edwards Plateau,
southern Rio Grande Plain, Central Gulf Prairies and Marshes, and Southern Gulf Prairies and
Marshes, ecoregions (Figure B6). The Rio Grande Plain along the border with Mexico
constitutes the northernmost range of several subtropical species that exist principally in Mexico
and Central America. The Big Bend area in the Chihuahuan Desert Basin and Range (due to
diverse topography) and Edwards Plateau (due to karst features) are known as centers of high
endemism.
There are several areas in Texas that show moderate and moderately high taxonomic
richness, but only very few areas show the highest numbers of rare taxa (Figure B7). In
particular, the Edwards Plateau is an area of high endemism due to the karst geologic features.
There are only very few areas that show the greatest number of rare species (or richness),
including the Big Bend area of the Chihuahuan Desert Basin and Range ecoregion in west Texas,
Sacramento-Manzano Mountains ecoregion (primarily the Guadalupe Mountains), Coastal Plains
and Flatwoods Western Gulf Section, parts of the Edwards Aquifer and Rio Grande Plain scored
in the highest percentage (i.e., most rare number of species) (Figure B8).
178
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Sustainability layer
Calculation of contiguous land cover types shows that there are larger portions of these
ecoregions with contiguous land cover types in the Rio Grande Plain, Chihuahuan Desert Basin
and Range, Stockton Plateau, Edwards Plateau, northern portions of the Texas High Plains, and
portions of the Rolling Plains (Figure B9). This may be due to larger unbroken tracts of a single
land cover type (i.e., shrubland or desert community types) compared to other areas of the state.
In the eastern half of the state, Blackland Prairie, Oak Woods and Prairie, and Mid Coastal Plain
Western Section, there may be more different types of undeveloped land cover, but none are
very large. These areas lack the connectivity of the west.
Figure BIO shows the locations where the perimeter-to-area ratio is small, and therefore
ecological communities more sustainable. Land cover types with smaller PAR are scattered
through the Rolling Plains, Cross Timbers and Prairie, Blackland Prairie, Oak Woods and
Prairie, Mid Coastal Plain Western Section, Gulf Coast Prairies and Marshes, and Coastal Plains
and Flatwoods Western Gulf Section. These areas are the top 1% with the smallest PAR and
thus, more sustainable areas in Texas.
Areas that most closely match pre-settlement vegetation (Figure BID and have been less
disturbed by human activities are the Rio Grande Plain ecoregion, the Stockton Plateau, portions
of the Edwards Plateau and Chihuahuan Desert Basin and Range ecoregions. The eastern
portion of the state has been impacted more by human activity and the land cover types present
do not reflect pre-settlement conditions (Kuchler 1964).
Portions of the Chihuahuan Desert Basin and Range, Stockton Plateau, Rio Grande Plain,
Texas High Plains, and Coastal Plain and Flatwoods Western Gulf Section have the fewest
179
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number of dams per HUC and therefore are more sustainable (FigureB 12). Cross Timbers and
Prairies, Blackland Prairies, and Oak Woods and Prairies have areas in the top 25% most
sustainable areas in terms of waterway obstructions.
Road density (Figure B13) reflects populated areas and the means to connect them
throughout Texas. For example, IH35 connects Austin, San Antonio, and Dallas-Ft. Worth.
Consequently, this transportation corridor is well-developed with side roads and urban activities.
FigureB 14 shows the buffered locations of airports in Texas. Large population centers,
such as Dallas-Ft Worth and Houston, where there may be multiple airports are evident.
Several Superfund NPL sites are located near high population areas, including Houston,
San Antonio, and Dallas-Ft.Worth (FigureB 15).
The bulk of impacted stream segments not meeting their designated use (CWA Section
303(d)) are in the eastern half of the state where the majority of the water in Texas occurs
(FigureB 16).
Areas of poor air quality are located near the major cities in Texas: Houston, San
Antonio, Dallas, El Paso, and Midland-Odessa (Figure B17).
Most of the RCRA sites are located near the major population centers in Texas: Houston,
Dallas-Ft Worth, Austin , and San Antonio (FigureB 18).
The population centers and much of the agricultural activities are in the Blackland
Prairies, Texas High Plains, and Oak Woods and Prairies ecoregions. Additional urban and
agricultural activities are scattered throughout the Rolling Plains, Mid Coastal Plains Western
Section, and portions of the South, Central, and Eastern Gulf Prairies and Marshes ecoregion
(FigureB 19).
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1 - 25.9 (Less Appropriate Vegetation)
26-61.5
61.6-87.5
87.6 - 99.9
100 (More Appropriate Vegetation)
Figure Bl. Map of diversity sub-layer: appropriateness of land cover. This map is used to
produce the map of the diversity layer (Figure 5). Even though this map shows the entire state of
Texas, the measures included in the diversity layer were calculated for each ecoregion.
181
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0 (Smaller Area)
1
2-59
60-99
100 (Larger Area)
200
Figure B2. Map of diversity sub-layer: contiguous size of undeveloped land. This map is used
to produce the map of the diversity layer (Figure 5). Even though this map shows the entire state
of Texas, the measures included in the diversity layer were calculated for each ecoregion.
182
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-,••
0 - 35.9 (Less Diverse)
36-51.1
51.2-62.3
62.4-77.5
77.6-100 (More Diverse)
200
Figure B3. Map of diversity sub-layer: Shannon land cover diversity index. This map is used to
produce the map of the diversity layer (Figure 5). Even though this map shows the entire state of
Texas, the measures included in the diversity layer were calculated for each ecoregion.
183
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0 (Absence of Streams)
100 (Presence of Streams)
150 200
Figure B4. Map of diversity sub-layer: ecologically significant stream segments. This map is
used to produce the map of the diversity layer (Figure 5). Even though this map shows the entire
state of Texas, the measures included in the diversity layer were calculated for each ecoregion.
184
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,,;#;^>,
>^^%-:
0 -1 (Less Rare)
2-6
7-16
17-60
61 - 250 (More Rare)
200
Figure B5. Map of rarity sub-layer: vegetation rarity. This map is used to produce the map of
the rarity layer (Figure 6). Even though this map shows the entire state of Texas, the measures
included in the rarity layer were calculated for each ecoregion.
185
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150 200
Figure B6. Map of rarity sub-layer: natural heritage rank. This map is used to produce the map
of the rarity layer (Figure 6). Even though this map shows the entire state of Texas, the
measures included in the rarity layer were calculated for each ecoregion.
186
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0 (Fewer Rare Taxa)
1 -28
29-110
111 - 250 (More Rare Taxa)
200
Figure B7. Map of rarity sub-layer: taxonomic richness. This map is used to produce the map of
the rarity layer (Figure 6). Even though this map shows the entire state of Texas, the measures
included in the rarity layer were calculated for each ecoregion.
187
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0 (Fewer Rare Species)
1 -17
18-86
87 - 250 (More Rare Species)
Figure B8. Map of rarity sub-layer: rare species richness. This map is used to produce the map
of the rarity layer (Figure 6). Even though this map shows the entire state of Texas, the
measures included in the rarity layer were calculated for each ecoregion.
188
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0 - 29 (Less Area)
30-91
92-99
100 (More Area)
Figure B9. Map of sustainability sub-layer: contiguous land cover type. This map is used to
produce the map of the sustainability layer (Figure 7). Even though this map shows the entire
state of Texas, the measures included in the sustainability layer were calculated for each
ecoregion.
189
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' -:-• • i :''^^;
0 -1 (Less Regular)
2-3
4-15
16-46
47-100 (More Regular)
200
Figure BIO. Map of sustainability sub-layer: regularity of ecosystem boundary. This map is
used to produce the map of the sustainability layer (Figure 7). Even though this map shows the
entire state of Texas, the measures included in the sustainability layer were calculated for each
ecoregion.
190
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1-25.9 (Less Appropriate)
26-61.5
61.6-87.5
87.6-99.9
100 (More Appropriate)
0 25 50
r
100
J
150 20
Miles
Figure B11. Map of sustainability sub-layer: appropriateness of land cover. This map is used to
produce the map of the sustainability layer (Figure 7). Even though this map shows the entire
state of Texas, the measures included in the sustainability layer were calculated for each
ecoregion.
191
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0 - 35.5 (More Obstruction)
35.6-56.1
56.2 - 99.9
100 (Less Obstruction)
200
Figure B12. Map of sustainability sub-layer: waterway obstruction. This map is used to produce
the map of the sustainability layer (Figure 7). Even though this map shows the entire state of
Texas, the measures included in the sustainability layer were calculated for each ecoregion.
192
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Hli 1
B^^iFft;^^ •- / /~ v
/
\ / / (
0 - 28.9 (More Roads)
29 - 42.3
42.4 - 99.9
100 (Fewer Roads)
200
Figure B13. Map of sustainability sub-layer: road density. This map is used to produce the map
of the sustainability layer (Figure 7). Even though this map shows the entire state of Texas, the
measures included in the sustainability layer were calculated for each ecoregion.
193
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0 (More Airport Noise)
100 (Less Airport Noise)
200
Figure B14. Map of sustainability sub-layer: airport noise. This map is used to produce the map
of the sustainability layer (Figure 7). Even though this map shows the entire state of Texas, the
measures included in the sustainability layer were calculated for each ecoregion.
194
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0 (Presence of Sites)
100 (Absence of Sites)
200
Figure B15. Map of sustainability sub-layer: Superfund NPL and state Superfund sites. This
map is used to produce the map of the sustainability layer (Figure 7). Even though this map
shows the entire state of Texas, the measures included in the sustainability layer were calculated
for each ecoregion.
195
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0 (Lower Water Quality)
100 (Higher Water Quality)
200
Figure B16. Map of sustainability sub-layer: water quality. This map is used to produce the
map of the sustainability layer (Figure 7). Even though this map shows the entire state of Texas,
the measures included in the sustainability layer were calculated for each ecoregion.
196
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0 (Lower Air Quality)
33
50
67
100 (Higher Air Quality)
150 200
Figure B17. Map of sustainability sub-layer: air quality. This map is used to produce the map of
the sustainability layer (Figure 7). Even though this map shows the entire state of Texas, the
measures included in the sustainability layer were calculated for each ecoregion.
197
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0 (Presence of Sites)
100 (Absence of Sites)
200
Figure B18. Map of sustainability sub-layer: RCRA TSD. corrective action and state VCP sites.
This map is used to produce the map of the sustainability layer (Figure 7). Even though this map
shows the entire state of Texas, the measures included in the sustainability layer were calculated
for each ecoregion.
198
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0 (More Disturbance)
100 (Less Disturbance)
r
0 25 50
r
\
J
100
150 200
Miles
Figure B19. Map of sustainability sub-layer: urban/agriculture disturbance. This map is used to
produce the map of the sustainability layer (Figure 7). Even though this map shows the entire
state of Texas, the measures included in the sustainability layer were calculated for each
ecoregion.
199
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APPENDIX C
List of Acronyms
200
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List of Acronyms
ATtlLA
BCD, TXBCD
C
C°
Ca
CD
CERCLIS
CO2
CrEAM
Cu
CWA
DEM
DO
EO
EPA
ESRI
F
Analytical Tools Interface for Landscape Assessments
TPWD Biological Conservation Database
Carbon
Celsius
Calcium
Compact Disc
Comprehensive Environmental Response, Compensation, and
Liability Information System
Carbon Dioxide
Critical Ecosystems Assessment Model
Copper
Clean Water Act
Digital Elevation Model
Dissolved oxygen
Executive Order
U.S. Environmental Protection Agency
Environmental Systems Research Institute
Farenheit
201
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FAA
Fed
FHWA
ft
FWS
GIS
GLO
G, GRANK
ha
Hg
HUC
ffl
K
km2, km
m2, m
mm
MRLC
N
NEPA
NGO
Federal Aviation Administration
Federal
Federal Highway Administration
Feet
U.S. Fish and Wildlife Service
Geographical Information System
General Land Office
Global natural heritage rank, TEAP variable
Hectare
Mercury
Hydrologic Unit Code
Interstate Highway
Potassium
Square kilometer, kilometer
Square meter, meter
Millimeter
Multi-resolution Land Characterization
Nitrogen
National Environmental Policy Act
Non-governmental Organization
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NHD
NLCD
NOAA
NPDES
NPL
NRCS
O
OAQPS
P
PAH
PAR
PNV
RCRA
RCRIS
SAB
Se
Si
SLOSS
S, SRANK
STORE!
T&E
National Hydrography Dataset
National Land Cover Dataset
National Oceanic and Atmospheric Administration
National Pollutant Discharge Elimination System
National Priority List (Superfund)
Natural Resources Conservation Service
Oxygen
Office of Air Quality Panning and Standards
Phosphorus
Polycyclic Aromatic Hydrocarbon
Perimeter-to-Area Ratio
Potential Natural Vegetation
Resource Conservation and Recovery Act
Resource Conservation and Recovery Information System
EPA Science Advisory Board
Selenium
Silicon
Single Large or Several Small
State natural heritage rank, TEAP variable
EPA Storage and Retrieval System
Threatened and Endangered species
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TCEQ
TEAP
TERS
THC
Texas Commission on Environmental Quality
Texas Ecological Assessment Protocol
Texas Environmental Resource Stewards
Texas Historical Commission
The Conservancy, TNC The Nature Conservancy of Texas
TIGER
TMDL
TPWD
TRI
TSMS
TSD
TxCDC
TXDOT
TWDB
USACE
USDA
USDI
USFS
USGS
VCP
Zn
Topological Integrated Geographic Encoding and Referencing
System
Total Maximum Daily Load
Texas Parks and Wildlife Department
Toxic Release Inventory
Texas State Mapping System
Treatment-Storage-Disposal sites
Texas Conservation Data Center
Texas Department of Transportation
Texas Water Development Board
U.S. Army Corps of Engineers
U.S. Department of Agriculture
U.S. Department of the Interior
U.S. Forest Service
U.S. Geological Survey
Voluntary Cleanup Program
Zinc
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APPENDIX D
List of Contributors
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Sharon Osowski, Ph. D.
US EPA Region 6
Ecologist
Preparation of TEAP report, analysis
TEAP report point of contact
Steering Committee Member
Jeff Danielson
US EPA
Lockheed Martin
GIS Specialist
Analysis of sustainability layer and
composite data
Steve Schwelling
TPWD
GIS Analyst
Report Reviewer
Analysis of rarity layer data
Duane German
TPWD
Biologist
Analysis of diversity layer data
Jim Bergan, Ph. D.
TNC
Science Director
TEAP Report Reviewer
Steering Committee Member
Malcolm Swan
TNC
GIS Specialist
Analysis of data for Accuracy
Assessment
Dominique Lueckenhoff
US EPA
Transportation Liasion
Steering Committee Member
Luis Fernandez, Ph.D.
US EPA
Environmental Scientist
TEAP Report Reviewer
David Parrish
US EPA Region 6
GIS Coordinator
Analysis of GIS data
A. Kim Ludeke, Ph. D.
TPWD
GIS Coordinator
TEAP Report Reviewer
Steering Committee Member
Russ Baier
TCEQ
Senior Policy Analyst
TEAP Report Reviewer
Steering Committee Member
Vicki Dixon
USAGE, Southwestern Division
Regulatory Program Manager
TEAP Report Reviewer
Steering Committee Member
John Machol
US ACE, Galveston District
TEAP Report Reviewer
Steering Committee Member
Ann Irwin
TXDOT
Director, Environmental Affairs Div.
TEAP Report Reviewer
Steering Committee Member
Sandra E. Allen
FHWA
IH69/TTC Environmental Coordinator
Steering Committee Member
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Jimmy Tyree
TxDOT
Environmental Planner
Steering Committee Member
David Certain, Ph.D.
TNC
Data accuracy assessment
TEAP Report Reviewer
Jack Bauer
TPWD
Director, Land Conservation
Steering Committee Member
Carlos Mendoza
FWS
Field Supervisor
Steering Committee Member
Norm Sears
US EPA
Life Scientist
TEAP Report Reviewer
Fred T. Werner
FWS
Biologist
Steering Committee Member
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