oEPA
United States
Environmental Protection
Agency
An Introduction to
Mid-Atlantic Seasonal Pools
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MID-ATLANTIC STATES
Cover photo credits
* USGSPWRC
** Lesley}. Brown
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EPA/903/B-05/001
June 2005
An Introduction to
Mid-Atlantic Seasonal Pools
Prepared for:
U.S. Environmental Protection Agency
Mid-Atlantic Integrated Assessment
701 Mapes Road
Fort Meade, MD 20755-5350
by:
Lesley J. Brown1
Robin E.Jung 2
1 Perot Systems Government Services
701 Mapes Road
Fort Meade, MD 20755-5350
2 USGS Patuxent Wildlife Research Center
12100 Beech Forest Road
Laurel, MD 20708-4038
Printed on chlorine free 100% recycled paper with
100% post-consumer fiber using vegetable-based ink.
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NOTICE
The U. S. Environmental Protection Agency (U.S. EPA) Office of Research and Development
(ORD), National Health and Environmental Effects Research Laboratory (NHEERL) and the
U. S. Geological Survey (USGS) Patuxent Wildlife Research Center, Amphibian Research and
Monitoring Initiative jointly funded the preparation of this manual through Student Services
Contract, Purchase Order Number 4D-5647-TTTX. Technical editing and graphics support
were funded by the U.S. EPA ORD, NHEERL through Interagency Agreement DW13939208-
01 with the U. S. Department of Commerce. U.S. EPA Region 3, Environmental Assessment
and Innovation Division, Environmental Programs Branch provided funding for printing. The
report was subjected to U.S. EPA's peer and administrative reviews and has received approval
for publication as an U.S. EPA document. This product has also cleared the USGS policy
review. Mention of trade names or commercial products does not constitute endorsement or
recommendation for use. The recommendations expressed in the manual are solely those of
the authors and do not necessarily reflect those of the sponsoring agencies.
The appropriate citation for this report is:
Brown, LJ. and R.E. Jung. 2005. An Introduction to Mid-Atlantic Seasonal Pools, EPA/903/B-
05/001. U.S. Environmental Protection Agency, Mid-Atlantic Integrated Assessment, Ft.
Meade, Maryland.
ABSTRACT
Seasonal pools, also known as vernal ponds, provide important ecological services to the
mid-Atlantic region. This publication serves as an introduction to seasonal pool ecology
and management; it also provides tools for exploring seasonal pools, including a full-color
field guide to wildlife. Seasonal pools are defined as having four distinctive features: surface
water isolation, periodic drying, small size and shallow depth, and support of a characteristic
biological community. Seasonal pools experience regular drying that excludes populations
of predatory fish. Thus, pools in the mid-Atlantic region provide critical breeding habitat for
amphibian and invertebrate species (e.g., spotted salamander (Ambystoma maculatum),wood
frog (Rana sylvatica), and fairy shrimp (Order Anostraca)) that would be at increased risk of
predation in more permanent waters.
The distinctive features of seasonal pools also make them vulnerable to human disturbance.
In the mid-Atlantic region, land-use changes pose the greatest challenges to seasonal pool
conservation. Seasonal pools are threatened by direct loss (e.g., filling or draining of the pool)
as well as by destruction and fragmentation of adjoining terrestrial habitat. Many of the species
that depend on seasonal pools for breeding spend the majority of their lives in the surrounding
lands that extend a radius of 1000 feet or more from the pools; these vital habitats are being
transected by roads and converted to other land uses. Other threats to seasonal pools include
biological introductions and removals, mosquito control practices, amphibian diseases,
atmospheric deposition, and climate change. The authors recommend a three-pronged strategy
for seasonal pool conservation and management in the mid-Atlantic region: education and
research, inventory and monitoring of seasonal pools, and landscape-level planning and
management.
KeyWords: seasonal pools; vernal ponds; wetlands; amphibian conservation; Mid-Atlantic;
aquatic ecology
An Introduction to Mid-Atlantic Seasonal Pools
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ACKNOWLEDGEMENTS
The authors would like to thank Tina Schneider of Maryland-National Capital Park and
Planning Commission, Patricia Bradley of U.S. Environmental Protection Agency (U.S. EPA)
Office of Research and Development (ORD), Eric Walbeck of Perot Systems Government
Services (PSGS), Ronald Landy of U.S. EPA Region 3 and ORD, Wayne Davis of U.S. EPA
Office of Environmental Information, and Marshall Howe of U.S Geological Survey (USGS)
Patuxent Wildlife Research Center (PWRC) for general support throughout the process, from
the initial planning stages to publication.
Thorough reviews of Section 3 and Field Guide to Seasonal Pool Fauna were provided by
Joseph C. Mitchell of the University of Richmond, Steven M. Roble of Virginia Department
of Conservation and Recreation, Dave Golden of New Jersey Division of Fish and Wildlife,
Thomas K. Pauley of Marshall University, Alvin Braswell of North Carolina State Museum of
Natural Sciences Research Laboratory, and Butch Norden of Maryland Department of Natural
Resources. Additional comments on Section 3 were provided by Robert T. Brooks of the U.S.
Department of Agriculture Forest Service, Mick McLaughlin of Clemmys Environmental
Services, and Jennifer Wykle of West Virginia Department of Natural Resources.
Many people were consulted; the authors particularly drew from the knowledge of Joseph
Mitchell, Butch Norden, Michael Hayslett of Holiday Lake 4-H Educational Center, Amy
Jacobs of Delaware Department of Natural Resources and Environmental Control, and Robert
Cook of Cape Cod National Seashore, National Park Service.
Comments on the manual were generously provided by Evan Grant, Priya Nanjappa, Rebecca
Chalmers, and Sandra Mattfeldt of USGS PWRC, Denise Clearwater of Maryland Department
of the Environment, Tina Schneider, Patricia Bradley, Stafford Madison of U.S. EPA Region 1,
and Naomi Detenbeck of the U.S. EPA Mid-Continent Ecology Division.
Special thanks go to the peer reviewers, who donated a great deal of personal time to improve
the accuracy and usefulness of the manual: Brian McDonald of West Virginia Natural
Heritage, Charles Bier of Western Pennsylvania Conservancy, William Sipple, retired U.S. EPA,
of WS. Sipple Wetland & Environmental Training & Consulting, and Aram Calhoun of the
University of Maine.
Juanita Soto-Smith of PSGS greatly assisted with desktop publishing and graphic design; Priya
Nanjappa kindly prepared the amphibian species distribution maps for Field Guides 1 and 2;
Kinard Boone of USGS PWRC assisted with several graphics.
Many photographers contributed to this publication; their names are noted on the
photographs. The authors especially thank Steven Roble, Solon Morse of Roger Tory Peterson
Institute (RTPI), Leo Kenney of the Vernal Pool Association, Bryan S. Windmiller of Hyla
Ecological Services, Alvin Braswell, John Bunnell of the Pinelands Commission, Tim Maret of
Shippensburg University and the USGS PWRC Amphibian Research and Monitoring Initiative
for their multiple donations.
Any mistakes in interpretation or otherwise are the sole responsibility of the authors.
Acknowledgement"
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CONTENTS
Notice i
Abstract ii
Acknowledgements iii
Section 1: Introduction to Seasonal Pools 1
1.1: Introduction 1
1.2: Purpose and Scope 2
1.3: Definition of "Seasonal Pool" 3
Section!: The Greater Seasonal Pool Ecosystem 7
2.1: Setting and Vegetation of Seasonal Pools 7
2.2: Life Zones of Seasonal Pools 10
2.3: Life Histories of Seasonal Pool-Dependent Organisms 14
Section 3: Introduction to Seasonal Pool Fauna 17
3.1: Introduction to Seasonal Pool Fauna 17
3.2: Indicator and Facultative Species 17
3.3: Salamanders in Seasonal Pools 21
3.4: Frogs and Toads in Seasonal Pools 23
3.5: Reptiles, Birds, and Mammals in Seasonal Pools 24
3.6: Invertebrates in Seasonal Pools 26
Section 4: Conservation Challenges Facing Seasonal Pools 27
4.1: Direct Loss of Seasonal Pools 27
4.2: Terrestrial Habitat Loss and Fragmentation 27
4.3: Other Conservation Challenges 31
Sections: Future Directions: Conservation
of Seasonal Pools in the Mid-Atlantic Region 33
5.1: Seasonal Pool Conservation in the Mid-Atlantic Region 33
5.2: Education and Research on Seasonal Pools 34
5.3: Inventory of Seasonal Pools 34
5.4: Landscape-Level Planning and Management 35
Field Guide to Seasonal Pool Fauna 37
Appendices 69
Appendix A: Techniques to Locate Seasonal Pools 69
Appendix B: Techniques to Monitor Seasonal Pools 73
Appendix C: Programs to Locate, Map, Monitor, and/or Protect
Seasonal Pools in the Mid-Atlantic Region 77
Appendix D: Sources of Additional Information on Seasonal Pools 81
Glossary 83
Literature Cited.., .. 85
An Introduction to Mid-Atlantic Seasonal Pools
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PLATES
Plate 1-1. Mid-Atlantic seasonal pool 1
Plate 1-2. Spotted salamander (Ambystoma maculatum) 1
Plate 1-3. A seasonal pool's wet stage and dry stage 4
Plate 1-4. Seasonal pools drying before metamorphosis 6
Plate 2-1. Seasonal forest pool 7
Plate 2-2. Seasonal open-canopy pool 8
Plate 2-3. Seasonal scrub-shrub pool 8
Plate 2-4. Seasonal forested wetland pool 9
Plate 2-5. Amplexus between a male and female
wood frog (Rana sylvatica) 11
Plate 2-6. Release of spotted salamander eggs 11
Plate 2-7. Recognizing dry seasonal pools 12
Plate 2-8. Spotted salamanders at pool edge 12
Plate 3-1. Spermatophores of spotted salamanders 21
Plate 3-2. Egg mass, larva, and adult salamander 22
Plate 3-3. Egg masses, tadpoles, and adult frog 23
Plate 3-4. Turtles of seasonal pools 24
Plate 3-5. Deer in an open-canopy seasonal pool 25
Plate 3-6. Fairy shrimp in seasonal pools 26
Plate 4-1. Aerial view of landscape fragmentation 27
Plate 4-2. Terrestrial habitat fragmentation 28
Plate 4-3. Spotted salamander roadkill 29
Plate 4-4. Garbage fills this seasonal pool 30
Plates
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FIGURES
Figure 1-1.
Hydrograph of a seasonal pool 4
Figure 2-1.
Seasonal pool aerial view delineating three life zones 10
Figure 3-1.
Distribution of amphibian indicator species in mid-Atlantic seasonal pools 19
Figure 3-2.
Breeding phenologies of seasonal pool indicator species 20
BOXES
Box 1-1
Ecological services provided by seasonal pools 1
Box 1-2
Definition of a seasonal pool 3
Box 1-3
Types of seasonal pools based on hydroperiod 5
Box 2-1
Example of regional seasonal pools: Delmarva bays 9
Box 2-2
Recognizing dry seasonal pools 12
Box 2-3
Life history of pool-breeding amphibians 14
Box 3-1
Indicator vs. facultative species in seasonal pools 18
BoxB-1
Practices for safely handling and reducing disturbance to amphibians 74
An Introduction to Mid-Atlantic Seasonal Pools
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,
INTRODUCTION TO SEASONAL POOLS
1.1: Introduction
Seasonal pools are dynamic habitats that have cycles
of standing water (Plate 1-1). These unique pools
fill with rainwater, surface runoff, snowmelt, or
groundwater in the fall, winter, or spring and may
completely dry out by the summer. Seasonal pools
are referred to by a variety of names, including
vernal pools, spring pools, ephemeral wetlands,
autumnal pools, woodland ponds, and temporary
ponds. Seasonal pools provide important ecological
services to the mid-Atlantic region (Box 1-1).
breeding are rare, threatened, or endangered in parts
of their mid-Atlantic range, such as the eastern tiger
salamander (Ambystoma tigrinum tigrinum) that is
state-listed as endangered in Delaware, New Jersey,
and Virginia. In the mid-Atlantic region, 26% of all
state-listed threatened and endangered amphibians
are dependent on seasonal pools.
Photo: TimMaret
Plate 1-1. Mid-Atlantic seasonal pool. This seasonal
forest pool is located in south-central Pennsylvania.
Box 1-1
Ecological services provided by seasonal pools
Important Breeding Habitat
Supply essential breeding grounds for
amphibians, including rare, threatened, or
endangered species.
Unique Invertebrate Community
Support a diverse invertebrate fauna,
including rare species.
Support of Aquatic and Terrestrial
Food Webs Supply food (amphibian
and invertebrate biomass) to wildlife
including amphibians, turtles, snakes,
birds, and mammals. Serve as "stepping-
stones" across the landscape for wetland-
or aquatic-dependent organisms.
Seasonal pools' periodic dry-downs exclude
permanent populations of predatory fish. This
reduced-predator environment provides critical
breeding habitat for certain species of amphibians
whose eggs and larvae would be at increased risk
of predation in more permanent waters. In the
mid-Atlantic region, seven species in the mole
salamander family (Ambystoma 5pp.), the wood frog
(Rana sylvatica), and the toad-like eastern spadefoot
(Scaphiopus holbrookii) depend upon seasonal pools
for their successful reproduction (Plate 1-2). The
fairy shrimp (Eubranchipus 5pp., Streptocephalus
sealii) and other invertebrates use seasonal pools
for their complete life cycle (Belk, 1975). Some of
the species that rely on seasonal pools for optimal
Photo: Steven M. Rome
Plate 1-2. Spotted salamander (Ambystoma
maculatum). Spotted salamanders are characteristic
members of seasonal pool biological communities of the
mid-Atlantic region.
Section 1: Introduction to Seasonal Pools
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Seasonal pools are inextricably linked to their
surrounding terrestrial landscape and support
aquatic and terrestrial food webs. Bordering and in-
pool vegetation provide organic material to seasonal
pools. Bacteria, algae, and fungi colonize this
vegetative matter, supplying food for invertebrates
and developing tadpoles. Invertebrates and
amphibian larvae are, in turn, prey for predatory
invertebrates and larger-sized amphibian larvae.
Amphibians and some insect species eventually
metamorphose, leaving the pools and providing a
major source of biomass (i.e., food for other wildlife)
to the surrounding terrestrial habitat.
Seasonal pools also serve as "stepping-stones"
through the landscape for animals moving among
wetlands. By providing feeding and watering
opportunities, they support local and regional
biodiversity. Developing amphibian larvae and
invertebrates in the pools are important prey for
visiting turtles, snakes, birds, and mammals.
1.2: Purpose and Scope
Seasonal pools support biological diversity by
providing important habitat. However, the same
qualities that make seasonal pools uniquely valuable
to wildlife render them especially vulnerable to
human disturbance. Their small size, surficial
hydrologic isolation, lack offish populations, and
impermanent water make them less likely to attract
attention for conservation. Also, they generally are
not protected by state or federal regulations. Many
seasonal pools may not meet the strict hydrologic,
soil, and vegetation requirements to be classified as
wetlands at the federal or state level (see Cowardin
et al., 1979) or may fall beneath the minimum
size requirements to be protected under wetlands
regulatory programs.
The United States has lost more than half of its
original acreage of wetlands due to draining, filling,
dredging, flooding, and leveling associated with
land development and agriculture (Dahl, 1990).
Although seasonal pools are not comprehensively
included in studies of wetland loss, partly because
methods that inform these studies do not work as
well for identifying relatively small seasonal pools, it
is highly likely that seasonal pools have been lost at a
rate equal to or exceeding that of the larger wetlands
included in these studies. The smaller the wetland or
pool, the less likely it is to fall under the jurisdiction
of federal or state wetlands regulations and the
easier it can be filled-in or drained. It is likely that
pools continue to be lost at a rapid pace in the mid-
Atlantic region.
The purpose of this publication is to introduce
readers to seasonal pool ecology and conservation
in the mid-Atlantic region, which is comprised of
Delaware (Del.), Maryland (Md.), New Jersey (N.J.),
Pennsylvania (Pa.), Virginia (Va.), West Virginia (W.
Va.), and the District of Columbia (D.C.). For many
readers, seasonal pools will be a new subject area or
serve as a new synthesis of ecological concepts.
This publication presents a working definition for
seasonal pools, describes landscape settings and
vegetative communities of seasonal pools, and
explores the seasonal pool ecosystem. Following
an introduction to seasonal pools and their fauna,
conservation challenges facing resource managers
and land-use planners wanting to conserve seasonal
pools are considered. The authors then put forward
recommendations for future directions in the
management of seasonal pool resources in the mid-
Atlantic region.
A pictorial Field Guide to mid-Atlantic seasonal pool
amphibians, invertebrates, amphibian larvae, and
amphibian egg masses is provided to aid readers in
the field. The Appendices present information on
techniques and references for surveying seasonal
pools.
An Introduction to Mid-Atlantic Seasonal Pools
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1.3: Definition of "Seasonal Pool"
In the mid-Atlantic region and elsewhere, seasonal
pools display tremendous diversity in terms
of landscape setting, surrounding vegetative
community, hydrological source (groundwater,
surface runoff, rainfall, snowmelt), hydroperiod, and
faunal communities, among other variables. The
definition of a seasonal pool must be broad enough
to encompass this variation.
For the purposes of this publication, we define
seasonal pools based on four distinguishing features:
surficial hydrologic isolation, periodic drying, small
size and shallow depth, and distinctive biological
community (Box 1-2; cf. Wiggins et al., 1980,
Calhoun and Klemens, 2002; Zedler, 2003; Calhoun
and deMaynadier, 2004; Colburn, 2004).
Box 1-2
Definition of a seasonal pool
0 Surficial Hydrologic Isolation
No permanent surface water connections
to other water bodies.
0 Periodic Drying
Water levels generally fluctuate by
season; pools experience drying or
lowered water levels on a regular basis
(frequency ranges from every year to just
drought years).
0 Small Size and Shallow Depth
Small area and shallow depth compared
to other productive aquatic habitats (such
as lakes and types of wetlands).
0 Distinctive Biological Community
Support animals that are adapted to
seasonal pool drying; support the
breeding of animals that reproduce
optimally without fish populations; do
not support permanent populations of
predatory fish.
Surficial Hydrologic Isolation
Isolation from other surface waters is one
of the defining characteristics of seasonal
pools. The lack of permanent surface water
connections protects pools from successful
invasion by predatory fish. There is a range in
the degree of isolation of pools, however. Some
pools are completely surrounded by terrestrial
environment with the nearest aquatic habitat a
half-mile or farther away, while other pools may
occur within a larger wetland complex.
Seasonal pools, despite being isolated from
permanent surface water connections, are very
much connected to the greater hydrology and
ecology of the landscape. Isolated pools may
receive their water from rainwater, surface water
run-off, snowmelt, subsurface flow, groundwater,
and possibly intermittent streams (Tiner,
2003b; Whigham and Jordan, 2003; Winter and
LaBaugh, 2003). Seasonal pools are connected
biologically to both aquatic and terrestrial
habitats by the movement of animals (Gibbons,
2003 ;Leibowitz, 2003).
Periodic Drying
Seasonal pools are water bodies that experience
alternating periods of filling and drying. Pools
in the Northeast, including the mid-Atlantic
region, typically begin to fill with water in mid-
autumn to early winter due to the onset of fall
rains and decreased water uptake by plants (i.e.,
the rate of evapotranspiration by trees lessens
due to leaf senescence) (Phillips and Shedlock,
1993; Brooks, 2004). However, some seasonal
pools may not begin filling until late winter or
early spring. Most seasonal pools reach their
maximum depth and size in the spring due
to snowmelt and spring rains. As spring and
summer progress with increasing temperatures
and rates of evapotranspiration by trees and
other vegetation, water levels decrease and pools
may dry completely (Plate 1-3; Fig. 1-1; Brooks,
2004).
Section 1: Introduction to Seasonal Pools
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Photos: USGS PWRC
Plate 1-3. A seasonal pool's wet stage and dry stage. A seasonal pool in Rock Creek Park, D.C., is
shown (A) in spring when the pool is full of water and (B) in fall when the pool has dried.
Seasonal pools display considerable variation in
hydroperiods (length of time that a pool is filled
with water) and water levels (depth at which the
pool is filled) across the landscape (Williams, 1987;
Semlitsch, 2000). The hydroperiod is the most
powerful abiotic factor determining the composition
of a seasonal pool community (Wiggins et al.,
1980; Skelly, 1997; Morey, 1998). The differences
between pools are due to regional climatic patterns
and characteristics of each pool's depression and
watershed (Brooks and Hayashi, 2002; Winter and
LaBaugh, 2003). In addition to these inter-pool
differences, a seasonal pool has intra-pool hydrologic
variability, with varying hydroperiods and water
levels over time, depending upon the season and the
weather conditions (Plate 1-3; Fig. 1-1; e.g., Rowe and
Dunson, 1993; Semlitsch et al., 1996; DiMauro and
Hunter, 2002).
45,
40-
o 35-
o
°- 30 H
•5
i"£25H
I
20-
15-
10-
5-
0
Pools reach their
maximum depth in earl
to mid spring through the
combination of spring
rain, snowmelt, and
groundwater inputs.
Precipitation may begin filling the
pool in fall or early winter.
Additionally the loss of leaves from
trees in the fall decreases the
amount of water that is lost from the
pool through evapotranspiration.
Pools begin decreasing in size and
depth in late spring through early fall
due to increased temperatures,
decreased precipitation, and
increased evapotranspiration. They
may eventually dry out completely.
Oct Nov Dec Jan Feb Mar Apr May Jun Jul Aug Sep
Figure 1-1. Hydrograph of a seasonal pool.* The water depth of a seasonal pool is shown according
to month of year. This hydrograph is meant to reflect a typical seasonal pool; individual pools will
have different depths and dates of filling and drying due to the characteristics of pool depressions and
precipitation and temperature patterns.
'Approximate water depths and dates were derived from Brooks (2004), Rowe and Dunson (1993), anddatasets of the U.S.
Geological Survey Amphibian Research and Monitoring Initiative - Northeast (USGS ARMI-NE, unpublished data).
An Introduction to Mid-Atlantic Seasonal Pools
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The umbrella term, "seasonal pool," that will be
primarily used in this publication, may be further
divided into three general types according to length
of hydroperiod, which may provide insight into
their respective biological communities: ephemeral
pools, annual pools, and semipermanent pools (Box
1-3). Due to differences in precipitation and weather
from year to year, pools have different durations and
timing of flooding from one year to the next. Thus,
the designation of a pool type based on hydroperiod
is for provisional descriptive purposes only.
Pools with hydroperiods of less than two months
during years of average rainfall are "ephemeral
pools." They are formed by intense periods of
precipitation. Ephemeral pools may be especially
valuable to species of clam shrimp (Class
Branchiopoda) and other invertebrates as well as
the reproduction of eastern spadefoots (Scaphiopus
holbrookii).
Box 1-3
Types of seasonal pools based on hydroperiod
Ephemeral Pools
Formed by intense periods of precipitation;
hydroperiods less than two months.
Annual Pools
Dry annually in typical years; hydroperiods
from 2 months to 12 months.
Semipermanent Pools
Undergo seasonal fluctuations in water levels;
do not dry annually; hydroperiods of greater
than 12 months.
Pools that dry annually and have hydroperiods of
2 months to 12 months are "annual pools." The
species composition of an annual pool community
may be different depending upon the length of the
hydroperiod.
At the other end of the spectrum, pools that do not
dry on an annual basis and have hydroperiods of
greater than 12 months are "semipermanent pools."
They still undergo significant seasonal fluctuations
in water levels and dry in years of relatively low
precipitation. Their surficial hydrologic isolation
and periods of very shallow and anoxic waters still
preclude permanent populations of predatory fish,
thus they may support seasonal pool-dependent
organisms. However, they may not support
organisms that depend upon complete dry-downs,
such as fairy shrimp. In addition, they may harbor
higher populations of predators, such as aquatic
salamanders and large-sized invertebrates (Semlitsch
et al, 1996; Skelly, 1997; Semlitsch, 2003).
Small Size and Shallow Depth
Most seasonal pools are very small compared to
ponds and lakes, which makes them more vulnerable
to pressures from development but does not make
them less valuable from a biological standpoint.
Their relatively small area and shallow depth are
what facilitates their dry periods or drawdowns
(Brooks and Hayashi, 2002). Their shallow depth
allows pools to warm rapidly, particularly important
for amphibians breeding during late winter and early
spring (Colburn, 2004).
According to the New Jersey Division of Fish and
Wildlife, most seasonal pools in New Jersey are less
than 0.25 acres (1,012 m2) in area (Tesauro, 2004).
On the Delmarva Peninsula, seasonal pools are
reported to be typically less than 0.4 acres (1,619 m2)
in size (Phillips and Shedlock, 1993). Many pools in
the mid-Atlantic region are much smaller than these
high-range figures suggest. In 2004, 134 seasonal
pools of natural origin with standing water and
containing wood frog and/or spotted/blue-spotted
salamander egg masses were surveyed at National
Parks and National Wildlife Refuges in the mid-
Atlantic as part of the USGS ARMI-NE program.
Pool area (maximum length x maximum width)
averaged 0.09 acre (379 m2) and ranged from 54 ft2
to 1.1 acres (5 to 4,350 m2), with 78% of the pools
less than 0.1 acre (400 m2). Pool maximum depth
averaged 15.4 inches (39 cm) and ranged from 2.8
to 78.7 inches (7 to 200 cm), with 69% of the pools
less than or equal to 15.7 inches (40 cm) maximum
depth (USGS ARMI-NE, unpublished data).
Section 1: Introduction to Seasonal Pools
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Distinctive Biological Community
Seasonal pools of the mid-Atlantic region support
characteristic communities of animals due to their
unique hydrology and their lack of permanent
populations of predatory fish. Many seasonal pool
inhabitants lack defenses against predatory fish,
and thus are primarily restricted to seasonal pools
(Wilbur, 1980; Kats et al, 1988). For example, larvae
of species of amphibians that breed in seasonal
pools may lack the ability to detect and evade fish
by using chemical cues and may be more palatable
as prey to fish as compared to species of amphibians
that typically breed in permanent waters (Kats
et al., 1988). Fish predation may annihilate the
entire brood of larvae of these species, resulting
in complete reproductive failure (Ireland, 1989).
However, not all species offish pose direct risks to
seasonal pool-breeding amphibians; for example,
some fish species feed primarily on plankton
(Hecnar and M'Closkey, 1997).
B
tf*
Photos: USGS PWRC
Plate 1-4. Seasonal pools drying before metamor-
phosis. Seasonal pools may dry before metamorphoses
of amphibians are complete. (A) A spotted salamander
(Ambystoma maculatum) egg mass remains in a dry
seasonal pool in Rock Creek Park, D.C. (B) Wood frog
(Rana sylvatica) tadpoles are left behind when a pool
dries up in Shenandoah National Park, Va.
Seasonal pool species display structural,
physiological, or behavioral adaptations to survive
and/or reproduce in these temporary waters
(Wiggins et al., 1980; Wilbur, 1980; Williams, 1987).
Amphibians and some species of invertebrates
metamorphose and leave the pool before it dries.
Certain species of invertebrates lay eggs that survive
the dry period; larvae or adults of some species may
burrow into the pool bottom. However, when there
is little rain in the spring, a pool can dry out too
quickly, causing embryos and amphibian larvae to
become desiccated and die (Plate 1-4; Shoop, 1974;
Semlitsch et al., 1988; Rowe and Dunson, 1993;
Skelly, 1997; Morey, 1998; DiMauro and Hunter,
2002).
Seasonal pools provide optimal breeding habitat
for nine species of amphibians across the region,
including seven species of mole salamanders in
the family Ambystomatidae as well as two anuran
species: wood frog and eastern spadefoot (see
Section 3 and the Field Guide for descriptions and
photographs of these animals).
Certain invertebrate taxa are common among
seasonal pool biological communities, including
crustaceans, mites, and three insect groups (true
bugs, beetles, and midges) (Williams, 1987;
Brooks, 2000; Colburn, 2004). The fairy shrimp
is a characteristic member of some seasonal pool
biotic communities; seasonal pools are the primary
habitats in which fairy shrimp species of the mid-
Atlantic region occur.
Depending on the weather, there may be years
when little or no breeding activity occurs in a pool
(Semlitsch et al., 1996). However, seemingly "empty"
pools may still support tremendous biodiversity in
years with favorable precipitation and temperature
patterns.
Seasonal pools may or may not be vegetated.
Although in-pool vegetation is not essential for
their role as important animal habitat, some
seasonal pools may support rare or endemic species
of vegetation, such as the Virginia sneezeweed
(Helenium virginicum), a state-listed threatened
plant endemic to sinkhole ponds of Virginia. More
research is needed to catalog these pool-dependent
species of flora.
An Introduction to Mid-Atlantic Seasonal Pools
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T
THE GREATER SEASONAL POOL ECOSYSTEM
The greater seasonal pool ecosystem is considerably
larger than the seasonal pool itself. It extends
outwards into the terrestrial landscape via biological
connections and the watershed via hydrologic
linkages. This section provides an overview of
the variety of landscape settings and surrounding
vegetative communities, explores the greater
seasonal pool ecosystem, and examines the general
life histories of seasonal pool-dependent fauna to
elucidate the nature of their interactions with the
seasonal pool ecosystem.
2.1: Setting and Vegetation of
Seasonal Pools
The mid-Atlantic region is a physiographically
diverse area of the United States, encompassing
the extremes of the low, flat, sandy mid-Atlantic
coastal plain to the greater than 5000 foot peaks
of the southern Blue Ridge Mountains of Virginia.
For example, Delmarva bays that are found on the
Delmarva Peninsula coastal plain of Maryland
and Delaware (Box 2-1) are very different
physiographically as compared to the seasonal
sinkhole ponds of the Shenandoah Valley of the Blue
Ridge Mountains (Buhlmann et al., 1999). Seasonal
pools of the mid-Atlantic reflect physiographic
diversity in their wide variety of landscape settings
and surrounding vegetative communities.
Seasonal pools can be found in three general
landscape settings: surrounded by upland, wetland,
or floodplain. Pools surrounded by upland are
islands of aquatic habitat within a terrestrial
landscape; pools surrounded by wetlands are part
of a larger wetland complex; pools surrounded
by floodplain are occasionally linked to a riverine
system.
Four basic classes of seasonal pools are described
below (seasonal forest pools, seasonal open-canopy
pools, seasonal scrub-shrub pools, and seasonal
forested wetland pools) based on their surrounding
vegetative community, with short lists of common,
but certainly not inclusive, species of vegetation that
may be found in or around these seasonal pools
(species were selected by referring to Tiner and
Burke, 1995; Rawinski, 1997; Buhlmann et al., 1999;
Sipple 1999; Zankel and Olivero, 1999; Colburn,
2004). Compositions of vegetative communities
vary from site to site due to local environmental and
historical conditions. Some pools may fall into more
than one class or may not easily be placed into one.
Additionally, vegetative communities are not static
- they may change across the seasons and over the
long-term (Tiner and Burke, 1995; Rawinski, 1997;
Colburn, 2004).
Seasonal Forest Pools
Seasonal forest pools are isolated depressions
surrounded by upland deciduous, mixed deciduous-
coniferous, or coniferous forest (Plate 2-1). These
pools may or may not be clustered in the landscape.
Trees that can tolerate seasonally-saturated soils,
such as white oak (Quercus alba), chestnut oak
(Quercus prinus), willow oak (Quercusphellos),
pin oak (Quercuspalustris), American elm (Ulmus
americana), loblolly pine (Pinus taeda), sweet gum
(Liquidambar styradflua), American beech (Vagus
grandifolia), and sourwood (Oxydendrum arboreum),
or trees with flood-resistant adaptations (e.g.,
buttresses, stilt roots) may be found around the
edges of the pool depression; a few may be found in
the pool itself, especially during high water levels.
Seasonal forest pools are partially or completely
Photo: Lesley J. Brown
Plate 2-1. Seasonal forest pool. This seasonal forest
pool is located in western Virginia.
Section 2: The Greater Seasonal Pool Ecosystem
-------
shaded by the overhanging tree canopy but there
is little or no plant growth in the pool depression
itself (Tiner and Burke, 1995; Rawinski, 1997; Sipple,
1999;Colburn, 2004).
Seasonal Open-Canopy Pools
Seasonal open-canopy pools have open canopies
that allow full sunlight to reach the pool (Plate 2-2).
The pools may be surrounded by upland, situated
within a larger wetland matrix, or in a floodplain.
They may be without vegetation or may be vegetated
with non-woody plant species. Emergent plants that
grow in these pools may include grasses (e.g., manna
grasses (Glyceria spp.), panic grasses (Panicum spp.),
giant plumegrass (Erianthus giganteus), rice cutgrass
(Leersia oryzoides)), sedges and rushes (e.g., sedges
(Carex spp.), creeping rush (Juncus repens), woolgrass
bulrush (Scirpus cyperinus), three-way sedge
(Dulichium arundinaceum)), and herbs (e.g., Virginia
meadow beauty (Rhexia virginica), marsh St. John's-
wort (Triadenum virginicum), Virginia chain fern
(Woodwardia virginica)).
Seasonal Scrub-Shrub Pools
Seasonal scrub-shrub pools are dominated by
shrubs or young trees less than 20 feet tall (6 m)
growing in the seasonal pool depression (Plate
2-3). Scrub-shrub pools may be surrounded by
upland forest, part of a larger wetland system, or
in a floodplain. Vegetation may include common
greenbrier (Smilax rotundifolia), highbush blueberry
(Vaccinium corymbosum), buttonbush (Cephalanthus
occidentalis), fetterbush (Leucothoe racemosa),
dangleberry (Gaylussaciafrondosa), swamp azalea
(Rhododendron viscosum), sweet pepperbush (Clethra
alnifolia), winterberry (Ilexspp.), alders (Alnus spp.),
and water willow (Decodon verticillatus).
,1 1 I
' - • i
A *••
Photo: USGS PWRC
Plate 2-3. Seasonal scrub-shrub pool. This seasonal
scrub-shrub pool is located at U.S. Department of
Agriculture's Beltsville Agricultural Research Center,
Md.
Photo: TimMaret
Plate 2-2. Seasonal open-canopy pool. This
seasonal open-canopy pool is located in south-central
Pennsylvania.
An Introduction to Mid-Atlantic Seasonal Pools
-------
Seasonal Forested Wetland Pools
Seasonal forested wetland pools are dominated
by flood-tolerant trees greater than 20 feet tall (6
m) growing in the pool basin (Plate 2-4). Seasonal
forested wetland pools may be surrounded by upland
forest or may be situated within a larger wetland
matrix, floodplain, or oxbow of a river. Trees may
include sweet gum (Liquidambar styradflua),
swamp black gum (Nyssa biflora), black gum (Nyssa
sylvatica), laurel oak (Quercus laurifolia), overcup
oak (Quercus lyrata), loblolly pine (Pinus taeda),
red maple (Acer rubrum), willow oak (Quercus
phellos), sourwood (Oxydendrum arboreum), water
oak (Quercus nigra), pin oak (Quercus palustris),
American elm (Ulmus americana), American holly
(Ilex opaca), sweet bay (Magnolia virginiana), willows
(Salix 5pp.), Atlantic white cedar (Chamaecyperis
thyoides), and green ash (Fraxinus pennsylvanica).
Photo: Gary P. Fleming
Plate 2-4. Seasonal forested wetland pool. A
seasonally flooded swamp forest of sweetgum
(Liquidambar styradflua), red maple (Acer rubrum),
and swamp tupelo (Nyssa biflora). This pool is located
in North Landing River Natural Area Preserve, City of
Virginia Beach, Va.
Box 2-1
Example of regional seasonal pools: Delmarva bays
Delmarva bays are an example of a type of seasonal
pool that is specific to an area of the mid-Atlantic
region. The Delmarva Peninsula is the projection of
land into the Chesapeake Bay that encompasses the
entire state of Delaware and portions of Maryland
and Virginia. On the Delmarva Peninsula, the
landscape is pockmarked with thousands of isolated
depressional wetlands or pools. These depressions
are known by many names, such as Delmarva bays,
Delmarva potholes, and whale wallows (Sipple,
1999). They are also sometimes categorized
within the larger category of coastal plain ponds or
equated with Carolina bays. 'Bay' refers to the trees
that are often found in these habitats: sweet bay
(Magnolia virginiana), red bay (Persea borbonia),
and loblolly bay (Gordon/a lasianthus) (Sipple,
1999). The coastal plain's relatively flat topography
favors the formation of seasonal pools, fed by
both groundwater and high levels of precipitation
experienced in this region (Tiner, 2003a).
Delmarva bays are of variable shapes and sizes -
elliptical, circular, or irregular with long-axes ranging
in length from less than 305 ft to 3050 ft (100 m
to 1 km) (Stolt and Rabenhorst, 1987). Their long-
axes are often oriented from north to south. They
generally have no standing water from midsummer
to early winter. Delmarva bays may form seasonal
open-canopy pools (known as 'glades') with Walter's
sedge (Carexwalteriana), giant plumegrass, twigrush
(Cladium mariscoides), and maidencane (Panicum
hemitomon); seasonal scrub-shrub pools with
buttonbush and water willow; and seasonal forested
wetland pools with red maple, sweet gum, and oaks
(Sipple, 1999).
Delmarva bays are particularly abundant in the
central area of the Delmarva Peninsula along the
border between Maryland and Delaware, in Queen
Anne's County and Caroline County in Maryland
and Kent County in Delaware (Stolt and Rabenhorst,
1987). Delmarva bays' abundance over the landscape
makes them important for surface water storage and
helps control local flooding. During wet seasons, they
serve as storage for groundwater discharge; during
dry seasons, they serve as sources of groundwater
recharge (Phillips and Shedlock, 1993). Delmarva
bays serve as important wildlife habitat, and support
many of the species described in Section 3.
Section 2: The Greater Seasonal Pool Ecosystem
-------
2.2: Life Zones of Seasonal Pools
The seasonal pool ecosystem can be thought of as
being composed of three integrated components,
or life zones: the seasonal pool depression, the
seasonal pool envelope (100 ft (30.5 m) radius
from pool edge), and the seasonal pool terrestrial
habitat (1000 ft (305 m) radius from the pool
edge) (Fig. 2-1; cf. Semlitsch, 1998; Calhoun
and Klemens, 2002; Calhoun and deMaynadier,
2004). Conceptualization of three discrete but
interdependent physical areas provides insight into
the overall functioning of the greater ecosystem
and allows tailored conservation strategies to be
developed (e.g., Calhoun and Klemens, 2002;
Calhoun and deMaynadier, 2004). All three zones
provide essential services that contribute to the
seasonal pool ecosystem. The three seasonal pool life
zones and the more prominent activities that they
host are briefly described below.
Seasonal Pool
Depression
Seasonal Pool
Envelope
100teet(30.5
000 ieet 1305 m)
Seasonal Pool
Terrestrial Habitat
Figure 2-1. Seasonal pool aerial view delineating three life zones.* The seasonal pool depression is the entire
area that fills with water during highest water levels. The seasonal pool envelope is the area immediately surrounding
the pool depression, extending 100 ft f (30.5 m) beyond the edge of the depression. The seasonal pool terrestrial
habitat is the area surrounding the pool that extends 1000 ft t (305 m) beyond the edge of the depression (inclusive
of the seasonal pool envelope).
t This width is based on the management zone designed by Calhoun and Klemens (2002).
$ This width was determined so as to encompass the movements and habitats of pool-breeding salamanders (e.g., Semlitsch, 1998; Faccio, 2003) and to
account for their high sensitivity to the amount of forest cover within this zone (e.g., Roman et al., 2004; Porej et al., 2004; Herrmann et al., 2005). However,
characteristics of the landscape (e.g., forest cover, road densities) at greater distances from the pool beyond this life zone may also affect seasonal pool fauna
(Homan et al., 2004; Porej et al., 2004; Herrmann et al., 2005). Additionally, juvenile wood frogs may migrate to other pools at distances significantly beyond
this life zone (average of 3750 ft (1140 m); Berven and Grudzien, 1990).
* Symbols used for diagram courtesy of the Integration and Application Network, University of Maryland Center for Environmental Science.
An Introduction to Mid-Atlantic Seasonal Pools
-------
Seasonal Pool Depression
The seasonal pool depression (also known as the
seasonal pool basin) is the area that fills with water
during highest water levels (Fig. 2-1). If there is no
standing water, other visual clues may indicate the
pool depression (Box 2-2; Plate 2-7). The seasonal
pool depression is the epicenter of the seasonal
pool ecosystem in late winter and spring, hosting
amphibian breeding, amphibian egg and larval
development, invertebrate life cycles, and wildlife
feeding.
Amphibian Breeding. Mole salamanders
(Ambystoma 5pp.) and wood frogs migrate
to the seasonal pool depression from their
overwintering terrestrial habitat from late winter
to spring, with the exception of the marbled
salamander (Ambystoma opacum), which
migrates to the depression in the fall. The exact
migration times or dates depends on the species,
region, and weather. Courtship and mating takes
place in the seasonal pool depression (Plate 2-5).
Photo: Steven M. Roble
Plate 2-5. Amplexus between a male and female
wood frog (Rana sylvatica). The male wood frog clasps
the female wood frog from behind while mating. There
are wood frog eggs on either side of the mating pair.
Amphibian Egg and Larval Development.
Depending on the species, female pool-breeding
amphibians lay their eggs singly, in strings, in
sheets, or as discrete masses immediately or a
few days after mating (Plate 2-6). Eggs and egg
masses of seasonal pool-breeders are usually
attached to vegetation or woody debris below the
water surface (Petranka, 1998). After hatching,
salamander larvae and tadpoles develop in the
pools. Salamander larvae eat zooplankton,
invertebrates, and, for larger individuals, other
amphibian larvae (Petranka, 1998); tadpoles
primarily eat algae and detritus, although they
may also eat smaller amphibian larvae and eggs.
Photo: Steven M. Roble
Plate 2-6. Release of spotted salamander eggs.
These female salamanders are laying egg masses in the
water of a seasonal pool.
Invertebrate Life Cycles. Seasonal pools provide
habitat for a wide variety of invertebrate species.
The soil at the bottom of seasonal pools may
contain resting eggs from species of crustaceans,
including fairy shrimp, clam shrimp, and seed
shrimp, and arthropods, including caddisfiies
(Dodson and Frey, 1991; Hilsenhoff, 1991; Smith,
2001). Adult amphibious snails, fingernail clams,
and amphipods may also survive dry conditions
or overwinter by burrowing into sediments and
organic debris (Smith, 2001).
Support of Terrestrial Food Webs. Invertebrates,
amphibians, reptiles, birds, and mammals
come to the pool depression to feed (Winfield
et al, 1981; Brooks and Doyle, 2001; Kenney
and Burne, 2001; Biebighauser, 2002; Colburn,
2004). Amphibian egg masses, invertebrate and
amphibian larvae, and emerging insects and
amphibians provide a significant food source
for visiting predators. Seasonal pools serve
as important feeding and watering sites for
wetland- or aquatic-dependent animals traveling
across the landscape.
Section 2: The Greater Seasonal Pool Ecosystem
-------
Box 2-2
Recognizing dry seasonal pools*
If there is no standing water, other visual clues
can be used to identify seasonal pools that fill
with water in another season.
Characteristic Topography
Depressions in otherwise flat topography
"Pit-and-mound" topography
Clues from Seasonal Pool Biota
Fingernail clams and clam shells
Caddisfly cases
Snails and snail shells
Fairy shrimp eggs
Evidence of Water
Stained or sediment-covered leaves
Trees with flood-resistant adaptations (e.g.,
buttresses, stilt roots)
Sphagnum moss, ferns
Wetland plants growing in dry soil
Wetland (hydric) soils
Water stains on trees
- Colburn, 1997; Tappan, 1997; Calhoun, 2003
- - . ••>• •v*,v-> "&-.:•
$$§&*:•:'
. .• J
.-•-,-••
• •..-
Photo: USGSPWRC
Plate 2-7. Recognizing dry seasonal pools. Water
stains at the base of trees presents evidence that this
area fills with water. This seasonal pool is located at the
Patuxent Research Refuge, Laurel, Maryland.
Seasonal Pool Envelope
The seasonal pool envelope is the terrestrial
habitat immediately surrounding the pool; it is a
management zone that extends approximately 100
feet (30.5 m) from the pool edge (Fig. 2-1; Calhoun
and Klemens, 2002; Calhoun and deMaynadier,
2004). This area supports activities related to
amphibian breeding, provides terrestrial habitat to
juvenile and adult amphibians, and plays a large role
in regulating water quality.
Amphibian Breeding. During the amphibian
breeding season (from late winter to spring for
most species), high densities of adult amphibians
may occupy the seasonal pool envelope (Plate
2-8; Calhoun and Klemens, 2002). They spend
their days hidden in this area near the edge
of the seasonal pool or in the pool itself, and
their nights in the pool engaged in breeding
activities. Male amphibians may arrive up to
several days or weeks earlier than females and
wait for females to arrive in this area (Bishop,
1941; Shoop, 1960; Semlitsch, 1981). Marbled
salamanders, unlike the other species in the mole
salamander family, breed in the late summer or
fall and may mate in the seasonal pool envelope.
Male marbled salamanders often intercept
females en route to the breeding pools, and
initiate courtship in the pool envelope before the
females reach the pool depression (Bishop, 1941;
Krenz and Scott, 1994).
Photo: USGSPWRC
Plate 2-8. Spotted salamanders at pool edge. These
salamanders are spending their daylight hours during
the breeding season under a cover object in the mud at
the margin of a seasonal pool.
An Introduction to Mid-Atlantic Seasonal Pools
-------
Juvenile and Adult Amphibian Habitat. From
summer to fall, the seasonal pool envelope
is occupied by large numbers of recently
metamorphosed juvenile frogs and salamanders.
They may burrow into the mud near the pool
edge or hide beneath rocks and logs to survive
dry weather before making their emigration
from the pools to their overwintering habitat
(Richmond, 1947; Shoop, 1974). Wintering
juvenile and adult wood frogs occur in greatest
densities within 30 m of pools and are highly
sensitive to disturbances in this area (Homan et
al, 2004; Regosin et al, 2005).
Water Quality. The seasonal pool envelope plays
a large role in regulating seasonal pool water
quality. Soil buffers run-off and snowmelt before
it enters the pool (Gascon and Planas, 1986).
Vegetation (tree roots and ground cover) traps
sediment before it enters the pool. Overhanging
vegetation regulates pool temperature and
supplies organic material to the pool depression;
leaf litter serves as food for fungi, bacteria, and
invertebrates (Colburn, 2004). Vegetation also
influences a pool's hydrologic regime - trees and
shrubs withdraw water from the pools, especially
in the spring and summer.
Seasonal Pool Terrestrial Habitat
Seasonal pool terrestrial habitat is the area that
extends 1000 ft (305 m) from the edge of the
seasonal pool depression (Fig. 2-1). The portion of
this life zone that remains forested or unimpacted
by human activities provides habitat to pool-
breeding amphibians and other wildlife, serves as a
terrestrial corridor between pools, and plays a role in
regulating water quality.
This management zone encompasses the habitat
of over 95% of populations of pool-breeding
salamanders (Semlitsch, 1998; Faccio, 2003),
although this area is not sufficient to encompass all
movements of seasonal pool-breeding amphibians
(e.g., juvenile wood frog migrations, Berven and
Grudzien, 1990). Also, the seasonal pool biological
community may be influenced by characteristics of
the landscape (e.g., amount of forest cover, densities
of roads) well beyond the seasonal pool terrestrial
habitat zone (Homan et al., 2004; Porej et al., 2004).
Amphibian and Other Wildlife Habitat.
Seasonal pool-breeding amphibians of the mid-
Atlantic region spend approximately 90% of
their juvenile and adult lives in the terrestrial
landscape (Semlitsch, 1998), and exhibit seasonal
variation in terrestrial habitat use. During the
winter, wood frogs find shelter and hibernate
in upland forests; during their more active
period, they forage and find shelter in moist
lowland forests (Hulse et al., 2001; Regosin et
al., 2003b). Spotted salamanders may occur at
uniform densities up to and exceeding 984 ft
(300 m) away from seasonal pools (Homan et
al., 2004). Seasonal pool-breeding amphibians
play important roles in forest ecology, as prey for
wildlife and as predators of invertebrates. In a
given area of forest, they may comprise a higher
biomass than the breeding birds and small
mammals combined (Windmiller, 1996). Many
other species of wildlife inhabit the seasonal
pool terrestrial habitat, including snakes, turtles,
birds, and terrestrial amphibians. They feed
on the resources produced in the seasonal pool
(Winfield et al., 1981; Brooks and Doyle, 2001;
Kenney and Burne, 2001; Biebighauser, 2002;
Colburn, 2004).
Biological Corridor. The terrestrial forested
habitat functions as a biological corridor,
whereby animals can travel between pools. Pool-
breeding amphibians and other animals may
disperse from one pool to another.
Water Quality. The water quality of the pool will
be determined by the entire watershed, which
will extend into the seasonal pool terrestrial
habitat and possibly even farther, depending
upon the characteristics of the watershed and the
source of the water.
Section 2: The Greater Seasonal Pool Ecosystem
-------
2.3: Life Histories of Seasonal Pool-
Dependent Organisms
Seasonal pool-dependent animals have developed
behavioral (e.g., effective immigration and
emigration strategies), physiological, or structural
adaptations that allow them to survive and/or
reproduce in the highly dynamic environment of
seasonal pools (Wiggins et al., 1980; Williams,
1987). Seasonal pool-dependent animals may be
classified into three general life history classes:
migratory breeders, non-breeding migrants, and
permanent residents (based on Colburn, 2004;
builds upon and modifies previous classification
systems of Wiggins et al., 1980; Williams, 1987).
This classification system is presented below, in the
context of mid-Atlantic seasonal pools.
Migratory Breeders
"Migratory breeders" are those animals that breed in
seasonal pool depressions during the flooded phase
and vacate pools during the dry phase (Colburn,
2004). The most visible members of this life history
grouping are pool-breeding amphibians (Box 2-3;
see Section 3 for more information).
Besides amphibians, some invertebrate species rely
on this life history strategy as well. Limnephilid
caddisfly adults spend summers in caves and tree
holes and return to the pools to breed (Colburn,
2004). Certain species of predaceous diving beetles,
backswimmers, and water boatman spend portions
of their life cycles in permanent water bodies away
from seasonal pools (Colburn, 2004).
Box 2-3
Life history of pool-breeding amphibians
Amphibian migratory breeders have biphasic
life cycles, requiring both aquatic and terrestrial
habitats (Semlitsch, 1998, 2003). Early stages
of development are spent as eggs and larvae in
seasonal pools. The transition from an aquatic to a
terrestrial life stage occurs at metamorphosis, when
amphibians emerge from their natal pools and enter
the terrestrial habitat.
As adults, they return to seasonal pools from their
terrestrial habitats to breed. Once having bred in a
particular pool, adult wood frogs have been found to
be very faithful to their pools (Berven and Grudzien,
1990). There is evidence that other pool-breeding
amphibians exhibit similar levels of breeding pool
fidelity (e.g., Ambystoma maculatum, Scott, 1994)
returning to the same pools and following the same
migration paths. Males arrive at breeding pools
earlier and stay later than females (Bishop, 1941;
Shoop, 1960; Semlitsch, 1981).
Dispersal between local populations occurs when
animals breed in pools other than their natal pools.
Dispersal in wood frogs and other seasonal pool-
breeding amphibians is age-specific, with juveniles
accounting for most or all of the movements between
ponds (Berven and Grudzien, 1990). Wood frogs
may emigrate more than 3750 ft (1140 m) from their
natal pools to breed as adults in other pools (Berven
and Grudzien, 1990).
The behavior and habitat requirements of the
terrestrial stage of pool-breeding amphibians are
not fully understood, primarily due to the logistical
difficulties in their study and the amphibians'
nocturnal and belowground habits (Petranka, 1998;
Dodd and Smith, 2003; Semlitsch, 2003). Pool-
breeding amphibians must keep their skin cool
and moist. Thus microclimates play a large role in
the suitability of a particular habitat for amphibians
(Gibbs, 1998; Guerry and Hunter, 2002); mature
forests provide appropriate microclimates (Semlitsch,
1981; Petranka et al., 1994; deMaynadier and Hunter,
1999; Rothermel and Semlitsch, 2002; Faccio, 2003).
Mole salamanders require sufficient belowground
refugia, which provide protection from predators and
freezing temperatures (Madison, 1997; Regosin et
al., 2003a). Mole salamanders may emigrate more
than 650 ft (200 m) from their breeding pools to their
terrestrial habitat (Semlitsch, 1981; Madison, 1997).
Females of pool-breeding amphibian populations
are more likely to overwinter at greater distances
away from pools compared to males (Regosin et al.,
2003a, b).
An Introduction to Mid-Atlantic Seasonal Pools
-------
Non-Breeding Migrants
"Non-breeding migrants" are those animals that
migrate to seasonal pools for feeding, rather than
breeding, a behavioral adaptation used to exploit
seasonal pool resources (Williams, 1987; Colburn,
2004). This group may include species of predaceous
diving beetles, turtles, snakes, birds, and mammals.
Freshwater turtles that frequent seasonal pools
generally feed on algae, terrestrial and aquatic plants,
and invertebrates. Snakes that have aquatic or semi-
aquatic life histories, such as the ribbonsnake, may
hunt for amphibians in the water of a seasonal pool.
Birds and mammals use seasonal pools as sources of
water and food (see Section 3).
Permanent Residents
"Permanent residents" are those animals that do not
spend significant amounts of time away from the
seasonal pool (Colburn, 2004). Permanent residents
are those with unique physiological and behavioral
adaptations to withstand drying and extreme
temperature changes. Some beetles, fingernail
clams, and other invertebrates spend the dry phase
or winter season aestivating in the sediment of pool
depressions. One of the most distinctive inhabitants
of some seasonal pools, fairy shrimp, as well as
species of flatworms, mosquitoes, and beetles,
survive pool drying as drought-resistant eggs or cysts
that hatch upon flooding (Smith, 2001). This life
history group also includes insects that spend their
larval stages in seasonal pools and become aerial as
adults but do not travel far from pools (Colburn,
2004).
Section 2: The Greater Seasonal Pool Ecosystem
-------
-------
I,
INTRODUCTION TO SEASONAL POOL FAUNA
3.1: Introduction to Seasonal Pool
Fauna
Seasonal pools provide important habitats for
invertebrates, amphibians, reptiles, birds, and
mammals. Amphibians are among the most
conspicuous visitors to seasonal pools, especially
between late winter and summer. During the
breeding season, congresses of salamanders and
choruses of frogs provide visual and auditory notice
of their presence. For a period of time after adults
breed and return to their terrestrial habitat, egg
masses and then larvae remain in the pool.
The hydroperiod of a seasonal pool plays a
significant role in determining the community
of animals it will support (Wiggins et al., 1980;
Semlitsch et al., 1996; Skelly, 1997; Morey, 1998;
Semlitsch, 2003). A hydroperiod shorter than one
month will not support the reproduction of most
seasonal pool-breeding amphibians. Conversely,
efficient predators of seasonal pool-dependent
species, such as aquatic salamanders, bullfrogs, and
large-sized predatory invertebrates, may potentially
colonize pools that have longer hydroperiods
(Thompson et al., 1980; Wilbur, 1980; Semlitsch
et al., 1996; Skelly, 1997; Semlitsch, 2003). A
given seasonal pool may be suitable habitat for
only a subset of seasonal pool-dependent species
(Zedler, 2003). Hydroperiod affects invertebrate
community composition, abundance, biomass, and
biological production (Leeper and Taylor, 1998).
As characteristics of pools change over time (e.g.,
succession of vegetation, lengthening or shortening
of hydroperiod), the amphibian and invertebrate
communities' species compositions may shift.
This section introduces the faunal communities
of seasonal pools. The Field Guide found on pages
37-68 provides more detailed information on these
species. It contains descriptions of the physical
characteristics, behavior, phenology, reproductive
biology, and geographic range of these species and
provides photographs to aid in their identification.
Note: This section and the Field Guide primarily focus
on the faunal communities of annual pools. Many of
these animals also successfully inhabit or breed in other
seasonal pools (i.e., ephemeral pools or semipermanent
pools). Additional research is needed to adequately
describe the faunal communities of ephemeral pools
and semipermanent pools.
3.2: Indicator and Facultative Species
Indicator species rely on seasonal pools as essential
habitat for a portion of their life cycles. These
species, sometimes also referred to as obligate
species, are dependent upon seasonal pools for
their continued existence (Box 3-1). Indicator
species have evolved to exploit seasonal pools: they
respond rapidly to the filling of the pool and their
populations persist through dry periods, due to
structural, behavioral, or physiological adaptations
(Wiggins et al., 1980; Williams, 1987; Zedler, 2003).
Indicator species of annual pools in the mid-Atlantic
region include nine species of amphibians (seven
species of mole salamanders, the wood frog, and
the eastern spadefoot) (Figure 3-1) and a crustacean
group (the fairy shrimp). As research on the natural
history of amphibians and invertebrates of seasonal
pools continues, there may be additional species that
are determined to be indicators.
Some of the amphibian indicator species may
sometimes breed in other pool types, such as small
permanent ponds, road-rut pools, or roadside
ditches (Petranka, 1998; Hulse et al., 2001; DiMauro
and Hunter, 2002). However, these alternate
breeding sites may result in reduced survival
of eggs and larvae. Roadside ditches and other
anthropogenic pools may dry too quickly to allow
species of amphibians to reach metamorphosis
(DiMauro and Hunter, 2002). More permanent
pools may harbor fish and other vertebrate predators
that prey heavily on developing invertebrates and
amphibians (Ireland, 1989). Seasonal pools represent
Section 3: Introduction to Seasonal Pool Fauna
-------
the most desirable breeding habitat for these
indicator species because of the higher likelihood of
successful reproduction.
There are also numerous facultative species that use
seasonal pools - the more common or significant
facultative species are included in this section and
the Field Guide. Facultative species use seasonal
pools for foraging, shelter, water, or breeding,
although they can successfully breed in other habitat
types (Box 3-1). Facultative species of seasonal pools
in the mid-Atlantic region include many aquatic
invertebrates, amphibians, turtles, snakes, birds, and
mammals.
Box 3-1
Indicator vs. facultative species in seasonal
pools
Indicator species REQUIRE seasonal pools for
optimal breeding conditions.
Facultative species USE seasonal pools
for obtaining food, water, temporary cover, or
breeding, although they can also successfully
breed in other habitats.
An Introduction to Mid-Atlantic Seasonal Pools
-------
Common
Name
Spotted
Salamander
Marbled
Salamander
Eastern
Tiger
Salamander
Jefferson
Salamander
Blue-
Spotted
Salamander
Mabee's
Salamander
Mole
Salamander
Wood
Frog
Eastern
Spadefoot
Scientific
Name
Ambystoma
maculatum
Ambystoma
opacum
Ambystoma t,
tigrinum
Ambystoma
jeffersonianum
Ambystoma
laterals
Ambystoma
mabeei
Ambystoma
talpoideum
Ran a sylvatica
Scaphiopus
holbrookii
STATES
Del.
Northern
1/2
Entire
Entire
X
X
X
X
Entire
Entire1
Md.
Entire except
southern
Eastern
Shore
Entire except
far western
Eastern
Shore &
southern tip2
Western
1/3
X
X
X
Entire
Southern &
eastern;
Eastern Shore
N.J.
Northern
3/4
Entire
Southern
1/3
Northern
1/3
Northern
1/3
X
X
Entire
Entire, though
scattered
distribution
in northern 1/2
Pa.
Entire
Scattered
distribution
southern &
eastern 1/2
1 county
Scattered
distribution
X
X
X
Entire
Parts of
eastern &
south-
central
Va.
Entire
Mainly
eastern &
southeastern
Southeastern
& 1 county
in Shenandoah
Valley
Western
(Blue Ridge,
Valley & Ridge,
Allegheny)
X
Southeastern
Isolated
south-central
Entire except
southeastern
Eastern &
southeastern;
scattered
western
distribution
W.Va.
Entire
Mainly
eastern,
southeastern,
& western
X
Scattered
distribution
(mainly along
Allegheny)
X
X
X
Entire though
scattered
distribution
Isolated,
scattered
distribution
Figure 3-1. Distribution of amphibian indicator species in mid-Atlantic seasonal pools.* Cells marked
with "X" indicate that the species is not currently present in that state. Fractions indicate the approximate
proportion of the state in which the species occurs.
1Not found north of Fall Line in extreme northern Del. (White and White, 2002); 2Extirpated from Charles
County, Md.;3Record from Chester County is historical; they are likely extirpated from Pa. (Hulse et al.,
2001); 4Hybrid populations of Jefferson and blue-spotted salamanders may occur in several locations in Pa.,
but genetic analyses need to be conducted to clarify this issue (Hulse et al., 2001).
* Distribution information for the mid-Atlantic states was primarily obtained from the ARMI National Atlas for
Amphibian Distributions (http://www.pwrc.usgs.gov/armiatlas/) and Petranka (1998). Information on ranges in
specific states was supplemented with Harris (1975) and White and White (2002) for Del. and Md., Schwartz and
Golden (2002) for N.J., Hulse et al. (2001) for Pa., Martof et al. (1980) and Mitchell and Reay (1999) forVa., and
Green and Pauley (1987) for W. Va.
Section 3: Introduction to Seasonal Pool Fauna
-------
Fairy Shrimp
Spotted
Salamander
Marbled
Salamander
Eastern Tiger
Salamander
Jefferson
Salamander
Blue-spotted
Salamander
Mabee's
Salamander
Mole
Salamander
Wood Frog
Eastern
Spadefoot
®
Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
(•) Time as egg l^^^^s. Time as adult fairy shrimp £^^^^ Time as larva (™")/paedomorph ( 1=1)
Time when metamorphosis is occurring <^^^^>=- Time as tadpole Brime when metamorphosis is occurring
Figure 3-2. Breeding phenologies of seasonal pool indicator species.* This chart displays the life stages
of indicator species in the mid-Atlantic region according to time of year. The combined length of the illustra-
tion and the green/white bar represents: the approximate time duration for when amphibian eggs and larvae
may be present, when eggs and adult fairy shrimp may be found, and when amphibian metamorphosis may
occur.
* References include Bishop (1941), Green and Pauley (1987), Tyning (1990), Petranka (1998), Hulse et al. (2001), Smith
(2001), Schwartz and Golden (2002), and White and White (2002).
An Introduction to Mid-Atlantic Seasonal Pools
-------
3.3: Salamanders in Seasonal Pools
Salamanders are four-limbed amphibians with
long tails and smooth skin that live in moist or
wet environments to avoid desiccation. In mid-
Atlantic seasonal pools, there are seven species
of salamanders that are indicators (Fig. 3-1, 3-2).
These salamanders are in the mole salamander
family, Ambystomatidae. The mole salamander
family derives its common name from the terrestrial
behavior of adults, who spend much of their
lifetimes underground, often in shrew or other
small mammal burrows, or beneath debris. These
salamanders emerge above ground primarily during
the breeding season when they migrate to and breed
in seasonal pools. Mole salamanders tend to be
very faithful to their breeding sites, often returning
each year (although individuals may skip years) to
the same pools following the same migration paths
(Box 2-3; Shoop, 1968; Stenhouse, 1985; Scott, 1994;
Windmiller, 1996).
On land, adult salamanders play important roles
in forest ecology as major predators of forest floor
arthropods and as prey to reptiles, birds, and
mammals (Windmiller, 1996). In seasonal pools,
smaller-sized ambystomatid salamander larvae
are a food source for backswimmers, predaceous
diving beetles, and other predators; larger-sized
(later-development stage) larvae may function as
top predators of aquatic invertebrates and other
developing amphibians, including conspecifics.
Salamanders may exert a controlling effect on
mosquito populations; mosquito larvae density
was 98% lower in wetlands with ambystomatid
salamanders compared to wetlands with no
salamanders (Brodman et al., 2003).
Ambystomatid salamanders have internal
fertilization with a sperm transfer mechanism
using spermatophores (Plate 3-1). Males deposit
spermatophores (sperm capsules atop conical
gelatinous bases) on pool bottoms, vegetation, rocks,
or land. Males court individually or in groups,
known as congresses, by performing underwater
courtship dances for the females (Tyning, 1990).
Photos: (A, B) Michael Male, (C) Steven M. Roble
Plate 3-1. Spermatophores of spotted salamanders. (A) A spermatophore is shown next to an underwater
salamander and (B) in close-up on a leaf. (C) Males deposit dozens of spermatophores on floors of pools.
Section 3: Introduction to Seasonal Pool Fauna
-------
Courtship stimulates a female to position herself
over the spermatophore and then pick up the sperm
capsule in her cloaca where internal fertilization
occurs (Pough et al., 2004). Females of some mole
salamander species (e.g., spotted, eastern tiger) lay
egg masses that are large and conspicuous (Plate 3-
2); others lay single eggs or short strands.
Larvae develop in water and have wide heads, bushy
external gills (three per side), and a long dorsal fin
that stretches from behind the head to the end of the
tail (Plate 3-2).
Ambystomatid salamanders are generally long-lived,
with some surviving 20 years or longer. Males may
be distinguished from females by their enlarged
cloacal glands (noticeable bulges under the base of
the tail) and more laterally compressed tails. In the
breeding season, pregnant females can be identified
by their enlarged sausage-like bodies full of eggs.
Photos: Steven M. Roble
Plate 3-2. Egg mass, larva, and adult salamander. (A) A spotted salamander egg mass, (B) blue-
spotted salamander larva, and (C) eastern tiger salamander adult represent the various life stages of
species of mole salamanders seasonal pools.
An Introduction to Mid-Atlantic Seasonal Pools
-------
3.4: Frogs and Toads in Seasonal Pools
Frogs are four-limbed, tailless amphibians.
Vocalizations, identifiable calls made primarily
by adult male frogs, play important roles in frog
behavior, including mating and defending territories
(Plate 3-3). Seasonal pool-breeding frogs have
external fertilization, with males releasing their
sperm onto eggs as they are deposited by females.
Many male frogs clasp their female partners from
behind while mating (a behavior called amplexus) to
ensure that their sperm fertilizes the females' eggs.
Frog egg masses are less cohesive than the egg masses
of most mole salamander species (Plate 3-3).
Eggs laid in the water hatch into aquatic larvae
(tadpoles) (Plate 3-3), which are primarily
suspension feeders; however, tadpoles of some
species may also feed on smaller-sized larvae or
amphibian eggs. Tadpoles undergo a remarkable
metamorphosis from herbivorous or omnivorous,
aquatic tadpoles to carnivorous, terrestrial adults
(Plate 3-3; Pough et al, 2004).
In mid-Atlantic seasonal pools, there are two species
of frogs that are indicators: the wood frog (Rana
sylvatica) and the eastern spadefoot (Scaphiopus
holbrookii). There are also many other facultative
species of frogs and toads that use mid-Atlantic
seasonal pools, among them: barking treefrog
(Hyla gratiosa), gray treefrog (Hyla versicolor/Hyla
chrysoscelis), upland chorus frog (Pseudacris feriarum
feriarum), and spring peeper (Pseudacris crudfer
crucifer) (see Field Guide, page 41).
•••• »..'(/ '"'-'
Mai- jH-jW-i^
•'"'IB ' «*i,.i MW f --JI-*.
Photos: (A) Tim Maret, (B, C) Steven M. Roble
Plate 3-3. Egg masses, tadpoles, and adult frog. (A) Egg masses, (B) recently-hatched
tadpoles, and (C) adult are the various life stages of the wood frog, a seasonal pool indicator
species. The adult wood frog pictured is a male making vocalizations.
Section 3: Introduction to Seasonal Pool Fauna
-------
3.5: Reptiles, Birds, and Mammals
in Seasonal Pools
There are many species of reptiles, birds, and
mammals in the mid-Atlantic region that feed on
prey in or near seasonal pools. Freshwater turtles
visit seasonal pools in the spring or summer to
feed on algae, terrestrial and aquatic plants, and
invertebrates; several species also feed on amphibian
eggs, larvae, and adults. Freshwater turtles maybe
observed in seasonal pools basking out of water on
emergent vegetation or logs during warm weather.
Spotted turtles (Clemmys guttata) inhabit shallow,
soft-bottomed freshwater habitats with aquatic
vegetation that are in close proximity to woodlands
(Plate 3-4). Spotted turtles feed in seasonal pools
extensively in the early spring; individuals have
been known to spend up to three to four months in
seasonal pools (Mitchell, 1994; Milam and Melvin,
2001). Other turtle species that visit seasonal pools
in the mid-Atlantic region include eastern snapping
turtles (Chelydra serpentina serpentina), eastern mud
turtles (Kinosternon subrubrum subrubrum), eastern
box turtles (Terrapene Carolina) (Plate 3-4), and
painted turtles (Chrysemyspicta) (Ernst etal., 1994).
Snakes that have aquatic or semi-aquatic life
histories may be observed hunting in seasonal pools.
More terrestrial snakes may also visit seasonal
pools to drink water or to feed, particularly when
amphibian larvae are concentrated in shallow pools
(J.C. Mitchell, pers. comm.). Snake species that visit
seasonal pools to feed primarily on amphibians
include, among others, northern watersnakes
(Nerodia sipedon sipedon), eastern gartersnakes
(Thamnophis sirtalis sirtalis), and eastern
ribbonsnakes (Thamnophis sauritus) (Ernst and
Barbour, 1989; Mitchell, 1994; Windmiller, 1996).
Photos: Steven M. Roble
Plate 3-4. Turtles of seasonal pools. (A) Eastern box turtles may aestivate in the mud of seasonal pools
during hot weather. (B) Spotted turtles visit seasonal pools to feed on invertebrates, amphibian eggs, and other
food items.
An Introduction to Mid-Atlantic Seasonal Pools
-------
Birds also prey on animals in or near seasonal pools.
Wading birds, such as great blue herons (Ardea
herodias) (Roble and Stevenson, 1998), waterfowl,
such as wood ducks (Aix sponsa), and woodland
birds visit the pools to feed on insect and amphibian
larvae. At coastal plain seasonal pools, yellow
legs (Tringa melanokuca, Tringaflavipes), little
blue herons (Egretta caerulea), and green herons
(Butorides virescens) feed on amphibian larvae
(Hassinger et al., 1970). Owls prey on amphibians
migrating to and from seasonal pools; birds of prey,
such as red-shouldered hawks, feed on seasonal pool
animals.
Seasonal pools also serve as important sources of
water and food for many mammals in the mid-
Atlantic region. Deer drink water and forage on
aquatic vegetation in seasonal pools (Plate 3-5).
Raccoons feed on amphibian larvae and adults, large
insects, and other inhabitants of seasonal pools
(Scale, 1982; Kenney and Burne, 2001). Shrews visit
seasonal pools to forage on insects (Winfield et al.,
1981; Brooks and Doyle, 2001). Bats visit seasonal
pools to drink water and to feed on flying insect
prey (Biebighauser, 2002). Scavenging carnivorous
mammals are likely to feed on animals trapped,
dying, or desiccated in the shallow drying or dried
beds of seasonal pools (Winfield et al., 1981),
including red fox, striped skunk, gray fox, bear, and
opossums.
Plate 3-5. Deer in an open-canopy seasonal pool.
White-tailed deer visit seasonal pools to drink water and
to forage on vegetation growing in and around the pool
basin.
Section 3: Introduction to Seasonal Pool Fauna
-------
3.6: Invertebrates in Seasonal Pools
Seasonal pools provide habitat to a wide variety of
invertebrate species. Invertebrates in seasonal pools
play important ecological roles, as a food source to
amphibians and other invertebrates, as consumers
of detritus, and as predators of smaller-sized
amphibian larvae and invertebrates.
Fairy shrimp, crustaceans in the Order Anostraca,
are an indicator group found in mid-Atlantic
seasonal pools. Fairy shrimp do not have defenses
against predators; therefore, they are very rarely
reported in pools with predatory fish and are found
in lower abundances in pools with predatory insects.
Adults appear in pools in late winter or early spring
before predatory insects reach maximum densities
(Wiggins et al., 1980). Five species of fairy shrimp
may occur in pools in the mid-Atlantic region,
although their distribution is not well known (Field
Guide; Belk, 1975; Belk et al., 1998). Fairy shrimp
glide upside-down and filter-feed microbes and
detritus from the water column or substrate (Plate 3-
6; Smith, 2001). Fairy shrimp produce eggs that can
survive the drying and freezing of pool sediments;
they may remain viable for many years before
finally hatching. Adult fairy shrimp have patchy
and unpredictable presence and abundance in pools
across the landscape. There is very little published
research on these animals in the mid-Atlantic
region.
In addition to the indicator fairy shrimp, there are
numerous facultative invertebrates found in or on
the surface of seasonal pools. The more distinctive
facultative classes and orders are included in the
Field Guide; the following is an incomplete list
of classes found in the seasonal pool invertebrate
community with the common names of some of
their members. Crustaceans include the classes
Branchiopoda (clam shrimp and cladocera),
Ostracoda (seed shrimp), Malacostraca (isopod and
amphipod), and Copepoda (copepod). Molluscs
include the classes Gastropoda (amphibious snail)
and Pelecypoda (fingernail clam). Arthropods
include the classes Insecta (predaceous diving beetle,
caddisfly larva, phantom midge larva, chironomid
midge larva, and mosquito larva) and Hydrachnidia
(water mite). Annelids include the classes Hirudinae
(leech) and Oligochaeta (aquatic oligochaete worm).
Plate 3-6. Fairy shrimp in seasonal pools. Seasonal pools may contain the indicator group of
crustaceans, the fairy shrimp. In pools where they occur, they may be abundant in the late winter or
early spring; notice the eleven pairs of swimming legs.
An Introduction to Mid-Atlantic Seasonal Pools
-------
—
CONSERVATION CHALLENGES FACING SEASONAL POOLS
Habitat loss and alteration associated with land
development present the greatest challenges to the
existence and health of seasonal pool ecosystems
in the mid-Atlantic region. Seasonal pools, and
the wildlife they support, are threatened by direct
loss (e.g., through filling or draining), as well as by
practices that degrade the pool: terrestrial habitat
loss and fragmentation, biological introductions and
removals, mosquito control practices, amphibian
diseases, atmospheric deposition, and climate
change.
4.1: Direct Loss of Seasonal Pools
The direct loss of seasonal pools due to draining,
filling, and dredging in association with human
activities presents a major threat to the persistence
of seasonal pool-dependent biota. According to a
U.S. Fish & Wildlife Service study, the following
land development activities accounted for losses
in freshwater wetlands in the time period between
1986 and 1997: 30% of losses were due to urban
development, 26% of losses were due to agriculture,
23% of losses were due to silviculture, and 20% of
losses were due to rural development (Dahl, 2000).
Although seasonal pools, because of their small sizes
and impermanent waters, were largely not accounted
for in these statistics, it is likely that they are being
lost in a similar manner.
Destruction of individual seasonal pools will
eliminate populations of permanent residents, such
as fairy shrimp, at those pools (Colburn, 2004). Also
at risk are migratory residents of seasonal pools.
Because of their limited dispersal abilities and site
fidelity to breeding pools (Berven and Grudzien,
1990; Scott, 1994), adult pool-breeding amphibians
are unlikely to make use of other pools in lieu of
lost pools. In fact, adult amphibians may continue
to return to the site of former (destroyed) pools
throughout their lifetimes, rather than seeking out
new breeding pools.
The loss of a seasonal pool may negatively impact
other seasonal pool communities in the surrounding
area. As seasonal pools and other wetlands become
fewer in number, the distances between pools
become greater, eventually exceeding the dispersal
abilities of amphibians and reptiles (Gibbs, 1993;
Semlitsch and Bodie, 1998; Gibbs, 2000). When
seasonal pools are destroyed, the number of
individuals that would have potentially dispersed
to other pools is reduced (Gibbs, 1993; Semlitsch
and Bodie, 1998), thus decreasing the rate of genetic
exchange among populations and potentially
inhibiting the rescue of locally declining or extinct
populations (Laan and Verboom, 1990; Marsh and
Trenham, 2001). For larger-bodied species that visit
pools for food (e.g., waterfowl), these increased
travel distances between pools may have important
energetic implications (Gibbs, 2000).
4.2: Terrestrial Habitat Loss and
Fragmentation
Urbanization, intensification of agriculture,
increased density of roads, and timber harvesting
have caused massive transformations of the
landscape in the eastern United States. Changes
in land-use in the mid-Atlantic region and their
consequences for wildlife habitat, landscape
connectivity (the extent to which the landscape
facilitates wildlife movement), and hydrology present
the largest challenges to seasonal pool conservation
(Plate 4-1).
Photo: Massachusetts Department ot Environmental Protection
Plate 4-1. Aerial view of landscape fragmentation.
This color infrared aerial photograph shows a seasonal
pool (dark circle marked by arrow) surrounded by
human development.
Section 4: Conservation Challenges Facing Seasonal Pools
-------
Biological Effects of Habitat Loss and
Fragmentation
Many of the wildlife species that use seasonal
pools for breeding and feeding spend the majority
of their lives in the forests and grasslands that
are being lost to increasing human development.
Thus, the conversion of terrestrial habitat directly
threatens many members of the biological
communities of seasonal pools by taking away
their sustaining environment.
Land conversion also indirectly affects seasonal
pool biological communities by restricting
wildlife movements and facilitating invasion
by disturbance-tolerant organisms. Land-use
changes translate into fragmentation of the
landscape, as forest patch to forest patch and
forest patch to seasonal pool distances increase
and the pathways of travel become more difficult
for animals to traverse (Plate 4-1).
The conversion of natural habitats (forests and
grasslands) to open land-uses, such as lawns,
agricultural lands, and impervious surfaces (i.e.,
any surface that prevents water from infiltration
into the soil, such as roads, buildings, and parking
lots) creates barriers to movement and decreases
landscape connectivity (Plate 4-2; Forman et
al., 2003). Amphibians have difficulty traversing
open landscapes due to higher temperatures and
lower soil moisture (deMaynadier and Hunter,
1999; Rothermel and Semlitsch, 2002; Rothermel,
2004). Studies have documented pool-breeding
amphibians' preference for forested habitat in the
eastern United States. Spotted salamanders and
wood frogs favor forests and avoid open-canopy
habitats in their migrations (Semlitsch, 1981;
Raymond and Hardy, 1991; Petranka et al., 1994;
deMaynadier and Hunter, 1999; Rothermel and
Semlitsch, 2002; Faccio, 2003). Mature forests
provide moist microhabitats for amphibians:
the thick leaf litter traps and stores moisture,
the coarse woody debris provides cover and
prevents soil drying, and a closed canopy with
an understory offers shade and slows evaporation
from the forest floor (Petranka et al., 1994). As
juveniles and adults, pool-breeding amphibians
are carnivorous, feeding on invertebrates such
as earthworms, snails, slugs, spiders, crickets,
beetles, and ants (Bishop, 1941; Petranka,
1998). They find this food in the leaf litter of
forested areas beneath woody debris and below
ground. Underground mammal burrows provide
protection for mole salamanders from predators
and freezing temperatures (Madison, 1997;
Regosin et al., 2003a). Destruction or degradation
of forested habitat as a result of poor forestry and
land development practices negatively impact
amphibian populations (Windmiller et al., 2006).
Photos: Bryan Windmiller
Plate 4-2. Terrestrial habitat fragmentation.
Conversion of land near seasonal pools for (A)
residential development, (B) golf courses, and other land
uses will impact the faunal populations of these pools.
An Introduction to Mid-Atlantic Seasonal Pools
-------
Fragmentation of the terrestrial landscape
inhibits migrations of amphibians between the
terrestrial habitat (where they spend greater
than 90% of their juvenile and adult lives) and
their breeding pools (Laan and Verboom, 1990;
deMaynadier and Hunter, 1999; Rothermel and
Semlitsch, 2002; Rothermel, 2004), decreasing or
arresting their reproductive success. Decreased
landscape connectivity may impede the dispersal
of individuals between ponds, reducing rates of
genetic exchange and potentially increasing the
risk of local extinctions (Reh and Seitz, 1990;
Laan and Verboom, 1990; Marsh and Trenham,
2001).
Roads, a pervasive and ever-increasing feature
of the human-altered landscape, affect the
survival and health of seasonal pool-dependent
wildlife populations and the persistence of
seasonal pools. Roads are a major source of
fatalities (both directly as road kill and indirectly
due to increased vulnerability to predators)
and present a formidable physical barrier to
animal migrations (Gibbs and Shriver, 2005).
Amphibians and reptiles that try to cross roads
experience high traffic mortality, particularly
during the mass seasonal migrations of frogs and
salamanders in early spring. Traffic mortality
may cause significant declines in amphibian
populations (Plate 4-3; Fahrig et al., 1995; Gibbs
and Shriver, 2005). Amphibians' small body size
makes overcoming man-made obstacles such
as levees, ditches, and curbed roads a slow and
difficult venture (Gibbs, 1998). Their small size
and slow speed also makes them very vulnerable
to predation when they are physically exposed
due to the human-altered landscape (Gibbs, 1998;
Rothermel, 2004).
The loss of reproductively-mature amphibians
killed en route to breeding pools will have a
significant impact on the population due to the
additional loss of all of their potential future
offspring (Dodd and Smith, 2003). The negative
ecological effects of road construction on wetland
biodiversity are cumulative over time (Findlay
and Bourdages, 2000). The loss of amphibian and
reptile species as a result of road construction may
take an average of eight years to detect, and the
full effects may not become apparent for decades
(Findlay and Bourdages, 2000). When a threshold
of road mortality has been crossed, populations
may go into rapid decline and eventually become
locally extinct (Gibbs and Shriver, 2005).
Watershed and ecological impacts of roads on
seasonal pools, such as altered wetland hydrology,
road salt pollution, and reduced amphibian
habitat and movement, may extend 984 ft (300
m) or more in each direction from a road edge
(Forman and Deblinger, 2000). For example,
the presence of tiger salamanders is negatively
associated with the cumulative length of paved
roads within 3281 ft (1 km) of their breeding
pools (Porejetal, 2004).
The extent and pattern of terrestrial habitat
degradation and loss that seasonal pool-
dependent animals can tolerate without
experiencing population declines and local
extinctions depends upon the characteristics of
the species and local conditions (Fahrig, 2002;
Homan et al., 2004). Amount of forest cover,
length and density of roads, and the degree of
wetland isolation (distance to nearest wetland
neighbor) have been shown to be among the
most important predictors of amphibian species
richness (Lehtinen et al., 1999; Porej et al., 2004;
Herrmann etal, 2005).
Photos: James P. Gibbs
Plate 4-3. Spotted salamander roadkill. Particularly
where roads separate seasonal pools from their
terrestrial habitat, road mortality is a serious threat to
amphibian populations.
Section 4: Conservation Challenges Facing Seasonal Pools
-------
Physical Effects of Habitat Loss and
Fragmentation
Land transformations in seasonal pools'
watersheds may directly affect the physical
properties of seasonal pools in a variety of ways.
These may include altered water chemistry,
altered water regime (decreased or increased
hydroperiods and higher or lower water levels),
temporal variation in hydrology, altered water
temperature, and increased sedimentation or
erosion. Physical impacts to the seasonal pool due
to land-use change, in turn, affect the biological
community. Land-use practices in the watershed
may alter the distribution of pool hydroperiods,
either by a change in the amount and timing of
water inputs to the pool or a change in the canopy
cover. Surface water run-off to pools in impacted
watersheds will have elevated temperatures due
to the elimination of overhanging canopy and
the path of water flow along heated impervious
surfaces (Schueler, 1994).
Roads act as conduits for pollution, channeling
fast-moving run-off that can contain car by-
products, road salts, sediments, lawn applications,
and other chemicals (Jones et al., 1992; Jones
and Sroka, 1997). Increasing impervious surface
area in a watershed potentially adds to the
amount of non-point source pollution entering
freshwater systems, including nutrients and
chemicals (Wernick et al., 1998; Sonoda et al.,
2001). Roadside seasonal pools have higher
specific conductance and higher sodium and
chloride levels compared to woodland seasonal
pools away from roads (Turtle, 2000). Land cover
change can also modify the quantity and type
of sediment input into freshwater bodies (Jones
et al., 2001). Pollution may affect seasonal pools
disproportionately more than other aquatic
habitats, such as rivers and lakes, because of the
pools' small size and isolation from other water
bodies. In late spring and summer, evaporation
may result in very high concentrations of ions
or toxins in the remaining seasonal pool water.
Also, seasonal pools are filled partially or entirely
by precipitation, runoff, and snowmelt that
have undergone little to no buffering by the
soil (Gascon and Planas, 1986; Wyman, 1990;
Whigham and Jordan, 2003). Thus local events
(such as nearby house or road construction)
may have a great impact on the pools' water
quality. Chemicals in the watershed, including
pesticides from agricultural, residential, and
industrial activities, may alter food web dynamics
and decrease populations of invertebrates or
amphibians (Boone and Bridges, 2003). Proximity
to human development also increases the risk of
pollution of pools by illegal dumping (Plate 4-4).
Photo: Michael S. Hayslett
Plate 4-4. Garbage fills this seasonal pool. This pool
in southern Virginia has been used as a trash dumping
site.
An Introduction to Mid-Atlantic Seasonal Pools
-------
4.3: Other Conservation Challenges
Biological Introductions and Removals
Seasonal pools may be dredged or impounded
for conversion to permanent water, for use as
farm ponds or stock tanks. Once the hydrology
is altered from seasonal to permanent, predators
such as bullfrogs and fish may invade the pool
and increase predation pressure on seasonal
pool-dependent animals. Purposeful introduc-
tions offish to seasonal pools for recreational
fishing and/or mosquito control may also occur,
which will likely have negative impacts on
indigenous species of amphibians (Thompson
et al, 1980; Hecnar and M'Closkey, 1997;
Kiesecker, 2003; Colburn, 2004). For example,
bluegill sunfish (Lepomis macrochirus) stocked in
a Shenandoah Valley sinkhole pond may be re-
sponsible for declines in eastern tiger salamander
populations (Buhlmann et al., 1999; Buhlmann
and Mitchell, 2000).
Seasonal pool-dependent amphibians are
collected as adults for consumption or laboratory
use, or as larvae for use as fishing bait. According
to a survey of fourteen scientific products
suppliers, nine suppliers offer species of mole
salamanders for sale for educational purposes
(Jensen and Camp, 2003). The majority of
these animals are likely captured in or around
wetlands and seasonal pools, rather than being
captive-bred (Jensen and Camp, 2003). Eastern
tiger salamander larvae are sold in baitshops
as "water dogs" (Jensen and Camp, 2003). The
cumulative impact of collection of seasonal pool-
dependent fauna is unknown in the mid-Atlantic
region.
Mosquito Control Practices
Mosquito control practices may target seasonal
pools. The most damaging practice employed
for mosquito control is the filling or draining of
seasonal pools. Other mosquito control methods
include the application of surface films (oils
added to ponded waters to suffocate mosquito
larvae), chemical larvicides, and biological
control agents. The effects of these mosquito
control practices on seasonal pool food webs and
pool-breeding amphibian eggs, larvae, and adults
have not been extensively studied (Colburn,
2004). However, it is known that these control
methods may impact groups of animals other
than mosquito larvae and negative effects may
take two years or longer to observe (Templeton
and Laufer, 1983; Hershey et al., 1998). Control
agents that reduce population sizes of plankton
and invertebrates may, in turn, affect pool-
breeding amphibians by reducing their food
supply (Boone and Bridges, 2003). Additionally,
the interaction of mosquito control techniques
with other anthropogenic stressors may
negatively impact the seasonal pool community
(Boone and Bridges, 2003).
Amphibian Diseases
Another threat posed to seasonal pool-dependent
amphibians is disease. Recent mortality events
and increased susceptibility to diseases may be
partially the result of reduced immune function
from increased stress associated with habitat
degradation (Blaustein and Kiesecker, 2002).
Chytrid fungus (Batrachochytrium dentrobatidis)
and ranaviruses can cause mass mortality in
amphibian larvae, metamorphosing individuals,
juveniles, and adults. These diseases may be
transported by field equipment, fishing gear,
or introduction of invasive species (Semlitsch,
2000; Carey et al., 2003). Ichthyophonus fungus
and ranavirus infections have caused deaths of
wood frog larvae and recently metamorphosed
individuals, and ranavirus has caused deaths
of spotted salamander larvae in seasonal pools
in the mid-Atlantic region (D.E. Green, pers.
comm.). For field work practices that minimize
the spread of these diseases, refer to Appendix B.
Atmospheric Deposition
Atmospheric deposition may impact the water
chemistry of seasonal pools to a greater extent
than other aquatic habitats because many
pools are primarily filled by precipitation and
Section 4: Conservation Challenges Facing Seasonal Pools
-------
surface run-off (Gascon and Planas, 1986;
Wyman, 1990). Acidification of pools through
acid deposition does not have straightforward
impacts on pool biological communities and
may differ according to characteristics of the
pool. Some studies show negative impacts of
low pH on amphibian reproductive success (e.g.,
Pough, 1976; Gascon and Planas, 1986; Sadinski
and Dunson, 1992) whereas others show no
measurable impacts (e.g., Cook, 1983; Albers and
Prouty, 1987). However, acidification elevates and
makes more soluble and hence more bioavailable
concentrations of metals in seasonal pool waters.
High levels of metals, such as aluminum, copper,
iron, lead, silicon, and zinc, may reduce hatching
success of amphibian eggs, reduce larval survival,
and increase the prevalence of amphibian
deformities (Albers and Prouty, 1987; Blem
and Blem, 1989,1991; Rowe and Dunson, 1993;
Home and Dunson, 1995; Jung and Jagoe, 1995).
Acid precipitation and atmospheric deposition
of metals from industrial and residential sources
may act synergistically to affect seasonal pool
communities.
Climate Change
Seasonal pools face uncertain impacts from
the climate change projected to occur over
the next century. In the mid-Atlantic region,
air temperatures and average precipitation are
projected to increase; however, precipitation
events are predicted to be of higher intensity
and more erratic in timing (U.S. EPA, 2001).
These precipitation and temperature patterns
have implications for hydroperiods and water
temperatures of seasonal pools, which will, in
turn, affect amphibian egg and larval survival
(Brooks, 2004). Climate changes may also
affect the seasonal timing of animal activity.
There is evidence to suggest that the warming
of the climate over the last century has affected
the breeding patterns of amphibians in the
northeastern United States (Gibbs and Breisch,
2001).
An Introduction to Mid-Atlantic Seasonal Pools
-------
FUTURE DIRECTIONS:
CONSERVATION OF SEASONAL POOLS IN THE MID-ATLANTIC REGION
5.1: Seasonal Pool Conservation in
the Mid-Atlantic Region
As yet, there are few comprehensive efforts to include
seasonal pools in natural resources management
in most of the mid-Atlantic States. The New Jersey
Division of Wildlife Endangered and Nongame
Species Program initiated a Vernal Pool Survey
Project in 2000, a statewide seasonal pool mapping
program. This project's goal is to locate, map, and
inventory seasonal pools statewide and monitor their
amphibian populations utilizing a trained group
of volunteers (Tesauro, 2004). A similar project,
the development of a web-based seasonal pool
registry and research program, is being prepared
for implementation in Pennsylvania by the Western
Pennsylvania Conservancy (see Appendix C).
In the other mid-Atlantic states, there have been
smaller-scale initiatives undertaken by governmental
agencies, nongovernmental organizations, and
coalitions. For example, the ARMI-NE of the USGS
and partners (U.S. Fish and Wildlife Service and
National Park Service) have located, mapped, and
surveyed amphibian populations at seasonal forest
pools in nine National Parks and National Wildlife
Refuges in the mid-Atlantic states (see Appendix C).
Unique systems of seasonal pools in the mid-
Atlantic region, such as sinkhole ponds in Virginia
and Delmarva bays in Delaware-Maryland, have
received attention by naturalists, academics, and
agency scientists (e.g., Rawinski, 1997; Roble,
1998; Buhlmann et al, 1999; Zankel and Olivero,
1999). However, there is a considerable need for
additional research on seasonal pools. Moreover,
existing studies have largely not been translated into
conservation or management programs.
Seasonal pools should be valued and managed as im-
portant ecosystems for support of biodiversity in the
mid-Atlantic region. In recent years, concern over
amphibian conservation has escalated due to reports
of declines in amphibian populations on a global-
scale (Barinaga, 1990; Stuart et al., 2004). Existing
amphibian monitoring efforts, such as the National
Wildlife Federation's FrogWatch and the USGS
North American Amphibian Monitoring Program,
provide data on frog and toad populations but do
not address the major cause of amphibian declines:
the loss of habitat including seasonal pools. There is
a need to bring a broader, landscape perspective to
the conservation of amphibians in the mid-Atlantic
region. There must be adequate protection and man-
agement of habitat, which for seasonal pool-breeding
amphibians includes the seasonal pool basin and
the surrounding terrestrial area that extends 1000 ft
(305 m) or farther from the edge of the pool. Char-
acteristics of the landscape up to 3281 ft (1000 m)
from the pool edge, such as amount of forest cover
or densities of roads, may also strongly influence the
presence and densities of amphibian species (Homan
et al., 2004; Porej et al., 2004; Herrmann et al.,
2005). For successful management of the seasonal
pool ecosystem, the seasonal pool itself should not
be considered separate from the terrestrial habitat.
The authors recommend that a three-pronged
approach be taken for conservation of seasonal
pools in the mid-Atlantic region. Simultaneous
efforts should be taken in the following areas:
education and research, seasonal pool inventory,
and landscape-level management. There needs to be
a targeted campaign to raise the level of awareness
and knowledge about seasonal pools, the reliance
of amphibians upon seasonal pools, and the threats
that face them. The audience of this campaign
should be broad, and include professionals as well
as the general public. It is also important to escalate
seasonal pool research efforts in the mid-Atlantic
region. Second, there needs to be a region-wide
initiative to locate and inventory seasonal pools in
order to determine their abundance, distribution,
and biological resources. Lastly, seasonal pools and
their associated life zones should be integrated into
landscape-level planning by local, county, and state
agencies and nongovernmental organizations. Pools
should be prioritized for conservation considering
several factors: the degree to which amphibians and
invertebrates depend upon them, the condition of
the terrestrial life zone, and the proximity to and
density of seasonal pools in the landscape (e.g., pool
clusters).
Section 5: Future Directions
-------
5.2: Education and Research on
Seasonal Pools
In order to facilitate successful seasonal pool
conservation efforts, stakeholders must be identified,
information must be disseminated, and the issue
has to be publicized. In addition, basic research on
seasonal pools in the mid-Atlantic region is needed
so as to inform efficacious management strategies.
0 Establish a Scientific and Management
Dialogue. Regardless of whether there
have been local or state efforts at seasonal
pool inventory or conservation, there are
individuals in each mid-Atlantic state who
are working with seasonal pool-related issues.
For example, there are nongovernmental
organizations working on amphibian
conservation research and policy, academics
and governmental agencies studying
amphibian populations, and naturalists
hosting educational programs in local
parks. These interested individuals should
be brought together. Workshops can be held
on locating seasonal pools using various
tools such as aerial photography and field
verification, or a mid-Atlantic seasonal
pools conference can be convened with the
participation of experts from states that have
seasonal pool programs in place, such as New
Jersey, Maine, and Massachusetts.
0 Increase Public Awareness. The level
of public awareness is very low. Amphibians,
such as spotted salamanders and wood frogs,
will likely be of greatest interest to the general
citizenry. The connection between seasonal
pools and these charismatic amphibians must
be made. The target audience should be broad
and include homeowners, school children,
and volunteers.
0 Raise Level of Knowledge. Many of the
studies on seasonal pools referred to in this
publication were carried out in areas other
than the mid-Atlantic region, particularly in
Maine, Massachusetts, and South Carolina.
More studies on the natural history, ecology,
hydrology, vegetation, and conservation
biology of seasonal pool ecosystems are
needed in the mid-Atlantic region. Research
partnerships should be explored between
academic institutions and governmental
agencies.
5.3: Inventory of Seasonal Pools
An important requirement for sustainable
management of a resource is an inventory of its
distribution and status. Currently, the number of
seasonal pools, their distribution in the landscape,
and their biological resources are unknown in the
mid-Atlantic region, although efforts are underway
in New Jersey and are beginning in Pennsylvania.
0 Locate and Inventory Seasonal Pools.
Seasonal pools in the mid-Atlantic region
need to be located and mapped with the data
assembled electronically and in CIS format
and fauna and flora must be inventoried.
This may best be carried out at the county-
or state-level through volunteer programs,
similar to the New Jersey's Vernal Pool
Survey Project. Another approach would
be standardizing and housing information
on seasonal pools and their fauna in a
federal program, similar to the way the
North American Breeding Bird Survey is
administered (see http://www.pwrc.usgs.gov/
bbs). (For techniques to locate seasonal pools
refer to Appendix A. For general information on
documenting seasonal pools refer to Appendix
B. For existing seasonal pool programs,
including New Jersey, refer to Appendix C.)
0 Monitor Seasonal Pools. Once
seasonal pools are identified, they should
be monitored. The rigor and method of
monitoring will differ according to the agent
undertaking the monitoring and the purpose
of the effort. For most seasonal pool efforts,
documenting the use of the pool by indicator
species (e.g., presence of spotted salamander
egg masses) may be sufficient. In other cases,
An Introduction to Mid-Atlantic Seasonal Pools
-------
more extensive population studies may be
carried out. Long-term, repeated sampling
of a subset of seasonal pools throughout the
mid-Atlantic region is essential to catalogue
the biodiversity and ecosystem health of
the pools and to determine amphibian
population trends. Herpetofauna that use
seasonal pools may take years or longer to
document and invertebrate communities
may undergo rapid shifts throughout the year
and between years (Mahoney et al., 1990;
Pechmann et al., 1991; Gibbons et al., 1997;
Simovich, 1998). Additionally, it is important
to record spatial and temporal changes in
seasonal pool communities and other biotic
and abiotic parameters in order to understand
and forecast responses of seasonal pool
communities to climate change, land-use
change, and other stressors.
5.4: Landscape-Level Planning and
Management
Successful seasonal pool conservation can only
occur when integrated into landscape-level planning.
All conservation plans must take into account the
three life zones described in Section 2. However,
in order to adequately protect the seasonal pool
biological community, seasonal pools require
customized, landscape-level approaches.
0 Acquisition and Protection of Intact
Habitats. Although every pool may have
value, nonregulatory natural resource
conservation tools such as acquisition and
conservation easements should initially target
seasonal pools that are particularly valuable
in terms of biodiversity support. Efforts
should be especially directed at protection
of contiguous tracts of forested terrestrial
habitat containing multiple seasonal pools.
Protection of clusters of pools with a range of
hydroperiods will provide the best probability
of long-term success in supporting indicator
species (Semlitsch, 2000).
0 Develop Best Management Practices.
Although protection of existing pools is the
highest priority for seasonal pool conservation
efforts, an active management approach
should also be taken to protect populations of
seasonal pool-breeding animals (Semlitsch,
2000). Best management practices (BMPs)
should be developed for pools with the input
of scientists and resource managers. For
example, management programs may include
the elimination of invasive fish species, the
control of sediment from development,
or prescribed burns (e.g., Tyndall, 2001).
Restoring or creating seasonal pools in
strategic locations may also be an effective
component of a management program
(Biebighauser, 2000), although designing
pools to have a specific hydroperiod and/or
support a particular community of organisms
may be difficult (Pechmann et al., 2001;
Lichko and Calhoun, 2003).
0 Create Best Development Practices.
Best development practices (BDPs) that focus
on lands surrounding seasonal pools need
to be established with the participation of
resource managers, state agencies, scientists,
private businesses, and land developers.
Recommendations should be outlined for
more sustainable development and forestry
practices based on the best available science.
BDPs for residential and commercial
development and forest habitat management
guidelines to protect seasonal pools have
already been developed for the northeastern
United States (Calhoun and Klemens, 2002;
Calhoun and deMaynadier, 2004). These
publications may be a useful tool, but BDPs
should also be formulated for the mid-
Atlantic region. BDPs will likely be different
for the mid-Atlantic region due to differences
in ecology, regulatory infrastructure, and
demographics as compared to New England.
Also, the process of developing BDPs with
the participation of all stakeholders is an
important consensus-building activity that
will greatly improve the chances of successful
implementation (Preisser et al., 2000).
Section 5: Future Directions
-------
0 Improve Transportation Planning.
Roads can be planned and designed to reduce
impacts on seasonal pools and their fauna.
Road construction that destroys seasonal
pools, occurs near seasonal pools, cuts
through the terrestrial habitat surrounding
seasonal pools, or separates pools from one
another should be prevented. If roads must
be built through terrestrial habitat or near
seasonal pools, road overpasses can be built
to allow biological and hydrological flows
to remain uninterrupted. Where this is not
possible, amphibian tunnels and other wildlife
underpasses in conjunction with barriers
can be constructed beneath roads to allow
migrations (Fahrig et al., 1995; Forman and
Alexander, 1998). Further research is needed
to design animal tunnels/underpasses so
that road mortality is reduced and landscape
connectivity is restored in the most effective
manner (Forman and Alexander, 1998; Dodd
and Smith, 2003). If these design features
cannot be installed, then road closures and
assisted amphibian crossings can be organized
to lower mortalities during major breeding
events.
0 Employ Regulatory Tools. Seasonal
pools that qualify as "waters of the U.S." are
under federal jurisdiction, which regulates the
disposal of dredge or fill material through a
permitting program (Section 404 of the Clean
Water Act). For the majority of seasonal pools,
which do not fall under federal protection,
alternative regulatory tools may be used in
order to secure greater levels of protection.
State and local wetland and forest regulations
may be strengthened to protect seasonal
pools and their surrounding terrestrial
habitat. Seasonal pools may be identified as
important wildlife habitat in comprehensive
land use plans (community master plans) or
overlay zones may be designed by the local
government and concerned stakeholders to
protect seasonal pools. The resource overlay
zones establish additional standards for
development projects on top of the underlying
zoning. These new zoning plans can be a
mixture of regulations and incentives to
conserve seasonal pools and their terrestrial
habitats (Nolon, 1998; Calhoun and Klemens,
2002). Voluntary stewardship programs may
be initiated whereby landowners conserve
their pools and follow best management/
development practices in adjacent forest areas
and receive tax credits or annual subsidies in
return (similar to the U.S. Fish and Wildlife
Service's Partners for Fish and Wildlife, see
http://northeast.fws.gov/partners) (Tiner,
2003a).
An Introduction to Mid-Atlantic Seasonal Pools
-------
FIELD GUIDE TO SEASONAL POOL FAUNA
The Field Guide is provided to help interested people identify members
of the seasonal pool biological community. Pictorial field guides are
included to aid the identification of adults, larvae, and eggs. For
those who wish to learn more about the natural history (physical
characteristics, behavior, phenology, and reproductive biology) of these
indicator species, in-depth information is also provided. Before exploring
seasonal pools, please refer to Appendix B for practices to prevent
negative impacts to pool animals (p. 74).
Contents
Members of the Seasonal Pool Community 37
Field Guide 1: Salamanders of seasonal pools in the mid-Atlantic region 38
Field Guide 2: Frogs and toads of seasonal pools in the mid-Atlantic region 41
Field Guide 3: Invertebrates of seasonal pools in the mid-Atlantic region 46
In-Depth Information on Seasonal Pool Indicator Species 49
Mole salamanders 49
Frogs 57
Fairy shrimp 60
Comparison of Eggs and Larvae of Amphibian Indicator Species 62
Field Guide 4: Amphibian eggs in mid-Atlantic seasonal pools 63
Field Guide 5: Amphibian larvae in mid-Atlantic seasonal pools 66
Field Guide to Seasonal Pool Fauna
-------
Field Guide 1: Salamanders of seasonal pools in the mid-Atlantic region.*
3.5 - 4.3 inches
(9-11 cm)
SPOTTED SALAMANDER
(Ambystoma maculatum)
Indicator Species
MARBLED SALAMANDER
(Ambystoma opacum)
Indicator Species
4.4-7.8 inches
(11 -20cm;
Bright yellow to
orange spots on
black to bluish-
black body
Habitat includes deciduous, mixed deciduous-coniferous,
and coniferous forests; breeds in seasonal pools
Protected: Del., N.J., Va.
Description: p. 49
Silvery-white or
gray markings or
bands on black body
Habitat includes deciduous, mixed deciduous-coniferous,
and coniferous forests; breeds in seasonal pool beds
Note: Unlike the other
Ambystoma spp. that breed
during spring, A. opacum
breeds during fall
Protected: Del., N.J., Va.
Description: p. 50
EASTERN TIGER SALAMANDER
(Ambystoma tigrinum tigrinum)
Indicator Species
JEFFERSON SALAMANDER
(Ambystoma jeffersonianum)
Indicator Species
4.3-7.5 inches
(11 -19cm
7-8.3 inches
(17-21 cm;
Yellowish markings
on dark brown or
black body
Habitat includes moist deciduous, mixed deciduous-
coniferous, and coniferous forests; breeds in seasonal
pools or fishless permanent pools; favors sandy soils
Endangered: Del., N.J., Va. Extirpated: Pa.
Threatened: Md.
Description: p. 51
Light blue-gray
flecks on brown or
gray body
Habitat includes deciduous forests; breeds in seasonal
pools or fishless permanent pools
Protected: N.J.,Va.
Description: p. 53
Watch list: Md.W.Va.
* General information is derived from Bishop (1941) and Petranka (1998). Salamander lengths represent total length of the body and tail.
Lengths are primarily from Conant and Collins (1998) and represent the range of average total lengths of these salamanders; where mid-Atlantic
literature provided dissimilar total lengths, the widest range of lengths was selected. Distribution maps are adaptedfrom the ARMI National
Atlas for Amphibian Distributions (http://www.pwrc.usgs.gov/armiatlas/). Maps may not accurately reflect the current presence of species in
counties (see website for more information).
An Introduction to Mid-Atlantic Seasonal Pools
-------
Field Guide 1: Salamanders of seasonal pools in the mid-Atlantic region.
BLUE-SPOTTED SALAMANDER
(Ambystoma laterale)
Indicator Species
MABEE'S SALAMANDER
(Ambystoma mabeei)
Indicator Species
3 -4.8 inches
(7.5-12 cm
3- 5.5 inches
(7.5-14 cm)
Bluish-white
spots on gray,
brown or black body
Habitat includes deciduous and mixed deciduous-
coniferous forests with rotting logs and deep humus;
also inhabits forests surrounding wetlands; breeds in
seasonal pools and fish-free ponds
Endangered: N.J.
Description: p. 54
White or gray
flecks on sides
of gray or black
body
Habitat includes pine savanna, wet wood, and swamp
habitats; breeds in seasonal pools
Threatened: Va.
Description: p. 55
MOLE SALAMANDER
(Ambystoma talpoideum)
Indicator Species
3 -4.7 inches
(7.5-12 cm)
Bluish-white or
gray flecks on
light brown to black body
Habitat includes hardwood forests or mixed pine-
hardwood forests; breeds in seasonal pools and fish-
free ponds
Special Concern: Va.
Description: p. 56
Field Guide to Seasonal Pool Fauna
-------
Field Guide 1: Salamanders of seasonal pools in the mid-Atlantic region.
RED-SPOTTED NEWT
(Notophthalmus viridescens viridescens)
Facultative Species
FOUR-TOED SALAMANDER
(Hemidactylium scutatum)
Facultative Species
Adult (above):
2.3 - 5 inches
(7- 13cm);
olive to brown
with distinctive
black-bordered red spots
Photos: Solon Morse. RTPI
Eft (below): 1.5 - 3.5 inches (4-9 cm); bright orange to
dull red with spots
Adult habitat includes wide-range of semi-permanent and
permanent waters
Efts (juveniles) are terrestrial
Protected: Del., N.J., Va.
2-4 inches
(5-10 cm)
Rusty brown
body with gray
sides; four toes on hind feet; white underside with black
spots
Habitat includes mature hardwood forests and oak-pine
forests; breeds in seasonal pools or other wetlands; lays
eggs above the water line; often nests in sphagnum and
other mosses
Protected: Del., N.J., Va.
An Introduction to Mid-Atlantic Seasonal Pools
-------
Field Guide 2: Frogs and toads of seasonal pools in the mid-Atlantic region.*
WOOD FROG
(Rana sylvatica)
Indicator Species
EASTERN SPADEFOOT
(Scaphiopus holbrookii)
Indicator Species
1.8-3 inches
(4.4-7.3 cm
1.4-2.8 inches
(3.5-7 cm)
Brown or red-
brown with
characteristic
chocolate mask; white underbelly; two ridges extend along
sides of back
Habitat includes moist or lowland deciduous woods; breeds
in fish-free seasonal and sometimes permanent pools
Protected: Del., N.J., Va.
Description: p. 57
Smooth skin with
scattered warts;
sharp black
spades on hind feet; vertical pupils and yellow eyes
Habitat includes floodplains of streams and rivers, woods,
meadows, or fields with loose, sandy soils; breeds in
seasonal pools
Protected: Del., N.J., Va.
Watch List: W. Va.
Description: p. 59
Note: Eastern spadefoots
primarily breed in seasonal
pools with short hydroperiods,
including ephemeral pools.
BARKING TREEFROG
(Hyla gratiosa)
Facultative Species
GRAYTREEFROG
(Hyla versicolor/Hyla chrysoscelis)
Facultative Species
2-2.6 inches
(5-6.6 cm)
Color changes
from light green
to brown; white stripe on upper lip extends down body
sides; usually has dorsal spots; large toe disks
Habitat includes coastal plain woodlands; breeds in
seasonal pools
Note: In parts of its
range, H. gratiosa may
be an indicator species.
Endangered: Del., Md.
Threatened: Va.
Photo: Farmscape Ecology Program, Hawthorne Valley Farm, NY
H. versicolor ||f| H. chrysoscelis
1.3-2.4 inches
(3.2-6 cm)
Highly variable
body color
changing from gray/green/brown; white spot under eye;
large toe disks
Habitat includes forest and seasonal pools, permanent
water, and swamps; breeds in seasonal pools
*•«.
Note: In the southern part
of its range, H. versicolor/
chrysoscelis may be an
indicator species.
Protected: Del., N.J., Va.
* General information on the frogs and toads is derived from Tyning (1990), Green and Pauley (1987), Hulse et al. (2001), Schwartz and Golden (2002), and
White and White (2002). All sizes given for frogs and toads represent 'snout to vent' lengths (SVL) and do not include the legs. Lengths are primarily from
Conantand Collins (1998) and represent the range of average SVL of these species; where the literature of the mid-Atlantic region gave different figures, the
widest range of lengths was selected. Distribution maps are adapted from the ARMI National Atlas for Amphibian Distributions (http://www.pwrc.usgs.gov/
armiatlas/). Maps may not accurately reflect the current presence of species in counties (see website for more information).
Field Guide to Seasonal Pool Fauna
-------
Field Guide 2: Frogs and toads of seasonal pools in the mid-Atlantic region.
PINE BARRENSTREEFROG
(Hyla andersonii)
Facultative Species
PINE WOODS TREEFROG
(Hyla femoralis)
Facultative Species
1.1-2 inches
(2.8-5 cm
Bright green body
with purple stripes
down sides; white
belly; large toe disks
Found in New Jersey Pine Barrens; breeds in seasonal
pools to permanent impoundments
Endangered: N.J.
1-1.5 inches
(2.5-3.8 cm)
Highly variable
body color
ranging from
reddish-brown to green-gray; row of very small orange,
yellow, or white spots on rear of thighs; large toe disks
Habitat includes pine flatwoods and cypress swamps on
coastal plain; breeds in seasonal pools
Protected: Va.
UPLAND CHORUS FROG/
NEW JERSEY CHORUS FROG
(Pseudacris feriarum feriarum/
Pseudacris feriarum kalmi)
Facultative Species
BRIMLEY'S CHORUS FROG
(Pseudacris brimleyi)
Facultative Species
1-1.3 inches
(2.5-3.3 cm
0.8- 1.4 inches
(2-3.6 cm
Brown or gray
with 3 dark stripes
or broken markings down back; dark stripes from snout to
groin, passing through the eye; small toe disks
Habitat includes grassy floodplains and wet woodlands;
breeds in shallow annual and semi-permanent pools/
wetlands
(P.f.f.) Protected: N.J.,Va. (P. f. k.) Protected: Del., N.J., Va.
Watch list: W. Va. Endangered: Pa.
black stripes down sides from snout to groin, passing
through eye; 3 brown or gray stripes down back; small
toe disks
Habitat includes wet woods and swamps of coastal
plain; breeds in shallow annual and semi-permanent
pools/wetlands
Protected: Va.
An Introduction to Mid-Atlantic Seasonal Pools
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Field Guide 2: Frogs and toads of seasonal pools in the mid-Atlantic region.
SPRING PEEPER
(Pseudacris crucifer crucifer)
Facultative Species
NORTHERN CRICKET FROG
(Acris crepitans)
Facultative Species
0.7- 1.3 inches
(1.9-3.3 cm
Variable body
color with brown
imperfect 'x'-
shaped mark on back; small toe disks
Habitat includes forest or field; breeds in shallow
seasonal or permanent pools and wetlands
Protected: Del., N.J., Va.
0.6- 1.4 inches
(1.6-3.5 cm)
Variable body
color; triangular-
shaped dark
mark between eyes; fully-webbed feet
Habitat includes moist areas near seasonal pools,
permanent water and streams; avoids dense vegetation
Protected: Del., N.J., Va.
EASTERN NARROW-
MOUTHED TOAD
(Gastrophryne carolinensis)
Facultative Species
NORTHERN/SOUTHERN
LEOPARD FROG
(Rana pipiens/Rana sphenocephala)
Facultative Species
0.9- 1.3 inches
(2.5-3.3 cm)
Variable color;
fold of skin across
back of head;
pointed snout
Habitat includes open and forested land; breeds in
shallow wetlands, seasonal pools, flooded fields, and
ditches
Protected: Va.
Endangered: Md.
Green and
brown with
irregular dark spots on back; cream dorsolateral ridges
Habitat includes grassy meadows and fields; breeds in a
variety of shallow wetland habitats
(Photograph is of Southern Leopard Frog)
(R.p.) Protected: Va. (R.s.) Protected: Del., N.J., Va.
Watch list: W. Va. Endangered: Pa.
Field Guide to Seasonal Pool Fauna
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Field Guide 2: Frogs and toads of seasonal pools in the mid-Atlantic region.
CARPENTER FROG
(Rana virgatipes)
Facultative Species
1.6-2.6 inches
(4-6.6 cm
Brown with
four coppery
stripes running
lengthwise on backs and sides
Habitat includes sphagnum bogs, Delmarva bays, some
beaver ponds, and swamps
Protected: Del., N.J., Va.
Special Concern: Md., Va.
PICKEREL FROG
(Rana palustris)
Facultative Species
1.8-3 inches
(4.4-7.6 cm)
Tan or brown
with dark brown
square blotches;
light-colored dorsolateral ridges
Habitat includes streams, marshes, meadows, and ponds
with thick marginal vegetation; breeds in a variety of
wetlands
Protected: Del., N.J., Va.
GREEN FROG
(Rana clamitans)
Facultative Species
AMERICAN BULLFROG
(Rana catesbeiana)
Facultative Species
3.5-6 inches
(9-15.2 cm);
largest frog in
mid-Atlantic
2-4 inches
(5-10.2 cm
Green to brown;
two dorsolateral
ridges extending two-thirds of the way down the back;
white underside
Habitat and breeding grounds include ephemeral to
permanent wetlands and other bodies of water including
streams
Protected: Del., N.J., Va.
Green to brown; no dorsolateral ridges; two ridges extend
on sides of face from eye around eardrum to shoulder
Habitat and breeding grounds include mostly deep,
sometimes shallow, semi-permanent to permanent bodies
of water
Can be a predator of seasonal pool amphibian eggs, larvae
and adults
Protected: Del., N.J., Va.
An Introduction to Mid-Atlantic Seasonal Pools
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Field Guide 2: Frogs and toads of seasonal pools in the mid-Atlantic region.
AMERICAN TOAD
(Bufo americanus)
Facultative Species
FOWLER'S TOAD
(Bufo fowleri)
Facultative Species
2-3.5 inches
(5- 9 cm
Brown with dark
brown spots
containing 1 to 2 warts; light mid-dorsal stripe may be
present; parotoid gland separated from ridge behind eye;
often has a spotted underside
Habitat includes woodlands, fields, and human-dominated
landscapes; breeds in permanent ponds, seasonal pools,
streams, ditches, and road ruts
Protected: Del., N.J., Va.
Brown with dark
brown spots
containing 3 - 7
warts; light mid-dorsal stripe often present; parotoid gland
in contact with ridge behind eye; unspotted underside
Especially common on Coastal Plain and in sandy areas;
breeds in seasonal pools and shallow edges of lakes and
streams
Protected: Del., N.J., Va.
Field Guide to Seasonal Pool Fauna
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Field Guide 3. Invertebrates of seasonal pools in the mid-Atlantic region.*
FAIRY SHRIMP
Crustacea C: Branchiopoda O:Anostraca
Indicator Species
Colorful bodies
0.5-2 inches (12-51 mm)
Swim upside down with their
11 pairs of legs in the water
column
Filter microbes and detritus
Resting eggs overwinter and
aestivate
Description: p. 60
CLAM SHRIMP
Crustacea C: Branchiopoda O: Laevicaudata/Spinicaudata
Facultative Species
Photo: Lesley J. Brown
Transparent to brown carapace
0.1-0.6 inches (2-16 mm)
Resemble lentils
Swim slowly with their legs
down or forward; associated with
aquatic vegetation and the pool
bottom; burrow in sediments
Consume detritus or collect
plankton
Resting eggs overwinter and
aestivate
Note: Clam shrimp inhabit
seasonal pools with short
hydroperiods, including ephemeral
pools. Some species of clam
shrimp may be indicator species for
ephemeral pools.
SEED SHRIMP
Crustacea C: Ostracoda O: Podocopa
Facultative Species
Variable color
Usually less than 0.04 inches
(1 mm)
Resemble miniature mussels or
seeds
Filter feeds detritus; may
scavenge dead or living animals
Found in sediments
CLADOCERA
Crustacea C: Branchiopoda
Facultative Species
"Water fleas" or "Daphnia"
Clear or transparent
Photo: Leo Kenney
Resting eggs can overwinter and aestivate
Less than 0.2 inches (5 mm);
folded carapace
Use antennae strokes for
movement; jerky locomotion
Filter feeds detritus, algae, and
bacteria
Photo: Leo Kenney
Parthenogenic eggs; also produces resting eggs that can
overwinter and aestivate
ISOPOD
Crustacea C: Malacostraca O: Isopoda
Facultative Species
Brown to light gray
Less than 0.7 inches (18 mm)
Flattened and broad-bodied; 7
pairs of legs
Crawl along pool bottoms
Consume detritus; scavenge on
dead organisms
Do not have physiological adaptations to withstand drying
Photo: Solon Morse, RTPI
AMPHIPOD
Crustacea C: Malacostraca O: Amphipoda
Facultative Species
"Scuds"
Variable color: pink, gray, or light
green
0.2 - 0.4 inches (5-10 mm);
narrow-bodied
Swim in quick bursts
Consume detritus; found among
detritus on pool bottom or buried
in soft-bottom
May survive short dry periods by burrowing in bottom
P = Phylum C = Class O = Order F = Family
* Invertebrates were selected for Field Guide 3 based on the results offieldwork conducted in seasonal pools by Mahoney et al. (1990), Leeper and Taylor (1998),
and Brooks (2000). Descriptions of these invertebrates were based on Wiggins et al. (1980), Kenney and Burne (2001), Smith (2001), Colburn (2004), and several
chapters from the edited volume of Thorp and Covich (1991): Dodson and Frey, Hilsenhoff, and Smith and Cook.
An Introduction to Mid-Atlantic Seasonal Pools
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Field Guide 3: Invertebrates of seasonal pools in the mid-Atlantic region.
COPEPOD
Crustacea C: Copepoda
Facultative Species
Up to 0.1 inches (2.5 mm)
Different species are filter
feeders or predators
Adults of some species may
form cocoons to survive
droughts; many species
produce eggs that may enter
diapause
AMPHIBIOUS SNAIL
P: Mollusca C: Gastropoda
Facultative Species
Photo: Leo Kenney
P: Mollusca C: Pelecypoda
Facultative Species
Shells are dull brown or light
gray; pink bodies
Feeds on detritus and algae
Some species are annual;
other species may
overwinter by burrowing in
frozen mud; also may burrow
in leaf litter or sediments to
survive dry season
Shells can be found in dry
pool beds
PREDACEOUS DIVING BEETLE
P: Arthropoda C: Insecta O: Coleoptera F: Dytiscidae
Facultative Species
Cream to light brown
Less than 0.5 inches (13 mm)
Filters detritus, algae, and
bacteria
Some species burrow in
sediments to survive dry periods
Shells can be found in dry
seasonal pool beds
CADDISFLY LARVA
P: Arthropoda C: Insecta O: Trichoptera
Facultative Species
Oval body shape; long linear
antennae
0.1 - 1.75 inches (2 - 45 mm)
Hind swimming legs are fringed
with hairs and kick simultaneously
Feed on invertebrates and
amphibian larvae
Some species survive dry periods
by burrowing in pool sediments, others by migrating to
permanent waters; some species lay diapausing eggs
Sheltered in self-constructed
cases
Two seasonal pool families:
1) Limnephilidae: "log cabin"
cases(above)
2) Phryganeidae: grass and
leaf cases (below)
Shred decaying leaves and
detritus; some species also feed
on mosquito larvae and amphibian egg masses
Live in seasonal pools and other aquatic habitats; adults
emerge before pools dry out; cases found in dry pool beds
Eggs may overwinter
Almost transparent; have distinct
heads
Less than 1 inch (25 mm)
Predators of insect larvae and
small crustaceans
Live in seasonal pools and
permanent waters; adults
emerge
Abundant in early spring
PHANTOM MIDGE LARVA
P: Arthropoda C: Insecta O: Diptera F: Chaoboridae
Facultative Species
Field Guide to Seasonal Pool Fauna
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Field Guide 3: Invertebrates of seasonal pools in the mid-Atlantic region.
CHIRONOMID MIDGE LARVA
P: Arthropoda C: Insecta O: Diptera F: Chironomidae
Facultative Species
0.1 - 0.8 inches (2 - 20 mm)
Often red due to hemoglobin-
like pigment
Worm-shaped and cylindrical
Can survive in low oxygen
levels as found in drying
seasonal pools
Found in pool bottoms and
open water; adults emerge
MOSQUITO LARVA
P: Arthropoda C: Insecta O: Diptera F: Culicidae
Facultative Species
0.3 - 0.5 inches (8-13 mm)
Have characteristic flip-flop
swimming motion; called
"wrigglers"
Feed on detritus and micro-
organisms
Live in seasonal pools and other
shallow waters; adults emerge
WATER MITE
': Arthropoda C: Hydrachnidia O: Acariformes
Facultative Species
Brilliant red or green, or brown,
tan, brown, yellow or blue
Less than 0.2 inches (5 mm)
Spherical and resembles tiny
spiders
Carnivorous or parasitic
Complex life cycle
Photo: Solon Morse, RTPI
PLANARIA
P: Platyhelminthes C: Turbellaria
Facultative Species
Flat and unsegmented
0.2 - 1.2 inches (5 - 30 mm)
Live for a year or less; some
species encyst themselves to
survive dry period
LEECH
P: Annelida C: Hirundinae
Facultative Species
Flattened and elongated; has
oral sucker and larger caudal
sucker
Parasites, scavengers,
or predators (of aquatic
invertebrate larvae and
amphibian eggs)
Some species can burrow
into pool bottom to survive
short dry seasons; some species produce drought-
resistant eggs
AQUATIC OLIGOCHAETE WORM
P: Annelida C: Oligochaeta
Facultative Species
Elongated;
up to 1.5 inches (38 mm)
Feed on leaf litter, detritus and
soil
Found among detritus and mud
in seasonal pools
Produce cocoons that protect
them from short periods of
drought
An Introduction to Mid-Atlantic Seasonal Pools
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IN-DEPTH INFORMATION ON SEASONAL POOL INDICATOR SPECIES
Mole Salamanders
For the salamander species detailed below, please refer to Field Guide 1 for photographs of adults
(p. 38), Field Guide 4 for photographs of eggs (p. 63), and Field Guide 5 for photographs of larvae
(p. 66). General information on the salamanders' physical appearance, habitat, and behavior is
primarily derived from Petranka (1998), Bishop (1941), and Tyning (1990). Species information
was tailored to the mid-Atlantic region by using Green and Pauley (1987), Hulse et al. (2001),
Schwartz and Golden (2002), and White and White (2002). When there was a range of figures
reported for certain parameters (such as egg clutch size), the figures from fieldwork in the mid-
Atlantic region were selected when possible, as is the case for this entire section. Salamander
lengths represent total length of the body and tail. The lengths are primarily from Conant and
Collins (1998) and represent the range of average total lengths of these salamanders; where mid-
Atlantic literature provided dissimilar total lengths, the widest range of lengths was selected.
Spotted Salamander (Ambystoma maculatum)
INDICATOR SPECIES
Adult Description: Spotted salamanders are 4.4 to 7.8 inches (11 - 20 cm) total length. These
salamanders have bright yellow or yellow-orange spots in two rows from head to tail on black,
bluish-black, brownish-black, or steel gray bodies (Field Guide 1). Their undersides are gray.
Habitat Requirements: As adults, spotted salamanders live primarily below ground, residing
in small mammal burrows and beneath logs and leaf litter. They feed on invertebrates (such
as earthworms, centipedes, spiders, and insects). Spotted salamanders inhabit moist, mature
deciduous forests as well as younger deciduous and mixed deciduous-coniferous forests.
Breeding occurs primarily in seasonal forest pools, seasonal forested wetland pools, and fish-
free ponds.
Reproduction: On moderate rainy or humid nights from mid-February through April,
spotted salamanders emerge from their terrestrial burrows and migrate to pools to breed
(Green, 1956; Nyman, 1991). At the pools, salamanders may gather in large congresses. The
breeding season may be several days to two months long, with one to three major breeding
events per season (Stenhouse, 1985; Harris, 1980; Petranka, 1998). Spotted salamander
breeding phenology (time frame in months when eggs, larvae, and metamorphs are present at
pools) for the mid-Atlantic region is shown in Fig. 3-2.
Eggs: Within hours to a few days following mating, females lay one to four egg masses on
submerged vegetation or debris about 8-10 inches (20 - 25 cm) below the water surface
(Field Guide 4; Bishop, 1941). Freshly laid egg masses are less than 1 inch diameter but expand
within hours as they absorb water (Bishop, 1941). Individual egg masses contain an average
of 75 - 110 eggs per mass (range of 15 - 250 eggs) (Bishop, 1941; Wood and Wilkinson,
1952; Shoop, 1974; Harris, 1980). Female spotted salamanders have total clutch sizes (total
number of eggs laid per breeding effort) of around 200 eggs (Woodward, 1982; Shoop, 1974;
Ireland, 1989). An egg mass is surrounded by a stiff gelatinous matrix, which is either clear or
opaque white (the latter is due to the presence of a crystalline protein). This gelatinous matrix
decreases predation, although adult red-spotted newts, predatory wood frog tadpoles, and
caddisfiy and midge larvae may still eat the embryos (Rowe et al., 1994; Stout et al., 1992). A
Field Guide to Seasonal Pool Fauna
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week after being laid, spotted and other mole salamander egg masses may begin to take on a
greenish hue caused by the growth of a symbiotic alga, Oophila amblystomatis, within the jelly
matrix. This alga derives nutrients from the jelly matrix and in turn provides oxygen to the
developing embryos (Bachmann et al., 1986; Finder and Friet, 1994).
Larvae: Spotted salamander larvae hatch from the eggs after about three to seven weeks,
depending upon water temperature. Larvae are only 0.5 inch (1 cm) in length at hatching
and grow quickly on a diet of zooplankton and other invertebrates to reach about 2 inches (5
cm) at metamorphosis. Larvae are greenish with light-colored underbellies and large feathery
gills (Field Guide 5). Spotted salamander larvae are preyed upon by predatory insects and
salamander larvae (e.g., marbled and eastern tiger) (Hairston, 1987).
Juveniles: Between six weeks and four months after hatching, mid-June through August,
larvae metamorphose into juveniles. Slowly growing larvae in some populations may
overwinter and transform the next spring (if the pool remains flooded) (Wilbur, 1977;
Phillips, 1992) though this has not been recorded for the mid-Atlantic region. Juveniles are
similar to adults but have lighter undersides and less prominent spotting on their backs. Sexual
maturity occurs after two to five years, with males typically maturing earlier than females.
Range: Spotted salamanders are found throughout the mid-Atlantic region, although they
tend to be absent from coastal areas.
Regional Notes: In Delaware, New Jersey, and Virginia, spotted salamanders are protected
(with limits set on take and collection). Major pressures on spotted salamander populations, as
with the other species of mole salamanders, come largely from habitat loss and deforestation.
Spotted salamander populations appear to have declined in eastern Virginia, which may be
related to acidic deposition and concomitant increases in concentrations of various metals
(aluminum, copper, silicon, and zinc) (Blem and Blem, 1989,1991; see Section 4.3).
Marbled Salamander (Ambystoma opacum)
INDICATOR SPECIES
Adult Description: Marbled salamanders are 3.5 to 4.3 inches (9-11 cm) total length and
thick-bodied with short tails. These salamanders are shiny black to purplish-black with silvery-
white or gray markings usually in crossbands, or as stripes in some individuals (Field Guide 1).
Males have larger, more distinct silver-white markings compared with females whose markings
are more blotchy and gray in coloration.
Habitat Requirements: Marbled salamanders spend most of their adult lives beneath leaf
litter, debris, stones, or below ground (up to 1 m in depth) in natural crevices and mammal
burrows. In summer and fall after rains, marbled salamanders can be found on the surface
of the forest floor. They inhabit deciduous forests as well as mked deciduous-coniferous and
coniferous forests. Marbled salamanders depend upon seasonal pools for breeding; only very
rarely will they breed in pools with fish.
Reproduction: Marbled salamanders exhibit a very different breeding behavior than the other
mole salamander indicator species. Breeding takes place during a different season and on
land rather than in the water. On rainy nights in fall (September to November) courtship and
mating begins en route to and in or along the margins of dry seasonal pool beds. In these dry
pools, females either find a naturally-occur ring depression (e.g., rodent burrow immediately
below leaf litter) or scour out their own that will serve as a nest for their eggs. The nest is an
An Introduction to Mid-Atlantic Seasonal Pools
-------
oval-shaped depression about 3 inches (7 cm) long, 2 inches (5 cm) wide, and 1 inch (2 cm)
deep (Tyning, 1990; Petranka, 1998). Nests are also created beneath logs and stones and at the
bases of grass clumps and trees (Bishop, 1941; Petranka, 1998). Marbled salamander breeding
phenology for the mid-Atlantic region is shown in Fig. 3-2. In an opposite pattern compared
to the other species of mole salamanders, marbled salamander adults breed earlier in their
northern range as compared to their southern range and earlier at higher altitudes as compared
to lower altitudes.
Eggs: Females lay 37 - 130 eggs in their nests (Green, 1956). Although nests are usually
individual, communal nests holding two to seven clutches have also been found (Petranka,
1998). Females often stay with their eggs, curling their bodies around them until the pool is
filled - which may be weeks or even months later. This behavior is thought to protect the eggs
from desiccation and predation by insects or small mammals. Females deposit eggs singly and
they often appear black due to clinging soil and detritus (Field Guide 4; Bishop, 1941; Petranka,
1998).
Larvae: Marbled salamander larvae hatch from eggs within a few days of being submerged by
pool flooding. If they hatch in the fall, the larvae will overwinter. During the cold months they
undergo only slow growth (Bishop, 1941), but during warm weather larvae grow quickly, first
eating zooplankton and later becoming voracious predators of invertebrates and amphibian
larvae including sibling marbled salamander larvae (Walls and Blaustein, 1995). In early
spring, marbled salamander larvae are likely to be larger in size than other amphibian larvae in
seasonal pools due to earlier hatching. Larvae are brown to blackish with a row of light spots
on their sides; older larvae develop mottling on a light yellowish-green body (Field Guide 5).
Their throats are darkly pigmented, which may distinguish them from lighter-throated spotted
salamander larvae.
Juveniles: The larvae begin transforming in the early spring and most leave the pool by May
or June. Recent metamorphs have purplish-black or brown bodies with a light-colored spotted
or speckled pattern; by one to two months after transformation, the adult pattern begins to
appear (Bishop, 1941). Sexual maturation occurs after one to five years.
Range: Marbled salamanders occur throughout the mid-Atlantic region, but appear to be
absent from northern and western Pennsylvania, eastern West Virginia, and western Virginia
(with the exception of a few scattered records).
Regional Notes: Like the spotted salamander, marbled salamanders are protected (with limits
set on take and collection) in Delaware and Virginia and are listed as special concern in New
Jersey. Loss of habitat - particularly bottomland deciduous forests and associated seasonal pool
habitats - poses the greatest threat to existing populations of marbled salamanders (Petranka,
1998).
Eastern Tiger Salamander (Ambystoma tigrinum tigrinum)
INDICATOR SPECIES
Adult Description: Tiger salamanders are among the largest pool-breeding or terrestrial
salamanders in North America. One of the approximately seven recognized subspecies, eastern
tiger salamanders are 7.0 to 8.3 inches (17-21 cm) total length with a thick body and broad
head. Eastern tiger salamanders are dark brown or dull black with a cream, greenish-yellow or
brownish-yellow pattern of irregular blotches or spots, sometimes forming tiger-like stripes
around their sides (Field Guide 1). They have yellowish undersides with dark marbling.
Field Guide to Seasonal Pool Fauna
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Habitat Requirements: Adult eastern tiger salamanders are fossorial, spending most of
their terrestrial lives in self-dug tunnels or in mammal burrows. They inhabit areas with
suitable conditions for burrowing (e.g., woodlands, open areas with sandy soils). Eastern tiger
salamanders breed in seasonal pools and fishless permanent ponds (Bishop, 1941; Wilbur and
Collins, 1973).
Reproduction: Tiger salamanders migrate to breeding pools from their underground
hideaways earlier than spotted salamanders on rainy or damp nights. Their breeding season
occurs from December to March across the mid-Atlantic region (Fig. 3-2; Cooper, 1955;
Anderson et al., 1971). The breeding season in New Jersey lasts about two months, which may
be longer than other mole salamanders in the area (Hassinger et al., 1970). They congress in
smaller groups compared to spotted salamanders (White and White 2002). Males produce
larger spermatophores than other ambystomatids.
Eggs: Females lay their eggs in globular or oblong gelatinous masses on twigs, weed stems,
and other structures in ponds at depths greater than 20 cm (Field Guide 4; Hassinger et al.,
1970). Egg masses measure 2.0 by 2.75 inches (5.5 by 7.0 cm) and swell in size and lose their
turgidity as they absorb water. Individual egg masses typically contain 30 - 60 eggs (Hassinger
et al., 1970; Stine et al., 1954; Bishop, 1941). Females have an average clutch size of 344 - 421
eggs (Wilbur, 1977; Stine et al., 1954).
Larvae: Eastern tiger salamander eggs hatch after four to seven weeks, depending upon water
temperature (Stine et al., 1954; Hassinger et al., 1970). Hatchlings have gray bodies with dark
bands across or blotches along their backs and whitish bellies; older larvae have olive green
bodies with markings (Field Guide 5). Eastern tiger salamander larvae are larger than other
Ambystoma spp. larvae in the region. Some larvae develop a cannibalistic morphology, typified
by larger size and enlarged teeth (though this has not been observed in the mid-Atlantic
region) (J.C. Mitchell, pers. comm.).
Juveniles: Larvae transform after two and a half to four months in late spring and summer.
Juveniles are initially dark gray or dark brown, and begin to attain adult coloration within one
month of transformation. Sexual maturation occurs generally when two to three years old
(Semlitsch, 1983).
Range: Eastern tiger salamanders are found mainly in eastern coastal areas of Delaware,
Maryland, southern New Jersey, and southeastern Virginia; they are not found in Pennsylvania
and West Virginia. There is also one relict population in the Shenandoah Valley (Blue Ridge
Mountains) of Virginia disjunct from other populations (Buhlmann and Hoffman, 1990;
Church etal., 2003).
Regional Notes: Tiger salamanders are listed as 'Endangered' in Delaware, Maryland, New
Jersey, and Virginia. They are considered extirpated from Pennsylvania as a result of habitat
alteration and loss (Hulse et al., 2001). The loss of vernal pools, Delmarva bays, and upland
forests is threatening these salamanders on the Delmarva Peninsula (Sipple, 1999; White and
White, 2002). Fish stocking and acid deposition also have contributed to declines of tiger
salamander populations in Virginia (Buhlmann et al., 1999).
An Introduction to Mid-Atlantic Seasonal Pools
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Jefferson Salamander (Ambystoma jeffersonianum)
INDICATOR SPECIES
Adult Description: Jefferson salamanders are 4.3 to 7.5 inches (11-19 cm) total length and
are slender with long tails and elongated limbs and triangular-shaped toes. They are chocolate
brown to dark gray and have light blue or gray speckles on their limbs, lower sides and tail
(Field Guide 1). Flecks are bright on young adults, but may fade with age. Their undersides are
lighter than their sides and are also speckled. Jefferson salamanders are physically distinguished
from blue-spotted salamanders by their slightly larger size, smaller markings, gray area around
the vent (as compared to black area in the blue-spotted salamander), and broader head.
Habitat Requirements: Juvenile and adult Jefferson salamanders spend a majority of their
lifetimes below ground, feeding on earthworms and other invertebrates. They reside in
deciduous forests, and are more likely than the other mole salamander species to live in upland
forests. In West Virginia, Jefferson salamanders have been found in caves (Green and Brant,
1966). Seasonal forest pools are the usual breeding location, but semipermanent pools, farm
ponds, and floodplain pools may also be used (Petranka, 1998).
Reproduction: In the mid-Atlantic region, Jefferson salamanders breed early in the spring,
beginning in February or March when evening rains coincide with temperatures of 40° F or
more (Fig. 3-2; Petranka, 1998; Hulse et al., 2001). Males often mount the female (dorsally
with forelimbs grasped behind the female's) for a time before more courtship occurs and
spermatophores are deposited. Jefferson salamander spermatophores are about twice the size
of those deposited by blue-spotted salamanders.
Eggs: One or two days after mating, female Jefferson salamanders deposit their eggs as masses
attached to submerged vegetation or unattached in the seasonal pool water. When attached to
solid structures such as twigs and branches, egg masses tend to be cylindrical and clumped in
groups; when attached to more vegetative substrates, such as grass, the egg masses are more
irregular in shape and laid further apart from each other (Field Guide 4; Petranka, 1998). Each
female lays up to 300 eggs in separate egg masses of 10 - 75 eggs (Martof et al., 1980, Hulse et
al.,2001).
Larvae: The eggs usually hatch after four to six weeks, but the embryonic period may last as
long as 14 weeks depending upon water temperature (Martof et al., 1980, Petranka, 1998).
Hatchlings are olive green to brown with hints of yellow on the sides of the neck, head and
dorsal fin (Field Guide 5). Mature larvae have grayish bodies with heavily mottled broad dorsal
fins, broad heads, elongated and tapered toes, and a silvery or white belly. Larvae are voracious
feeders, eating small zooplankton at first, then progressing to larger invertebrates, including
snails and insects. They are also known to eat spotted salamander larvae and other Jefferson
salamander larvae (Petranka, 1998).
Juveniles: The larval period lasts two to five months (J.C. Mitchell, pers. comm.). Metamorphs
are uniformly gray or brownish above with muted brownish yellow specks on the sides.
Jefferson salamanders become sexually mature after two to three years.
Range: Jefferson salamanders are patchily distributed in the mid-Atlantic states. They are
found in northern New Jersey, most of Pennsylvania, western Maryland, and along the Blue
Ridge and Allegheny Mountains of Virginia and the Allegheny Plateau of West Virginia. They
are absent from Delaware.
Field Guide to Seasonal Pool Fauna
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Regional Notes: Jefferson salamanders are on the watch list (special concern but without
legal protection) in Maryland and West Virginia, are of special concern in New Jersey, and are
protected (have limits set on take or collecting) in Virginia. Jefferson salamanders appear to
be more vulnerable to acidic conditions than other amphibians (Petranka, 1998). Jefferson
salamanders were designated by the Northeast Endangered Species Technical Committee
as a species of regional conservation concern due to their risk of extirpation (Therres,
1999). Jefferson and blue-spotted salamanders often hybridize in areas where their ranges
overlap, resulting primarily in female polyploids, which could lead to a reduction in pure
Jefferson salamander populations (Bogart and Klemens, 1997). In the mid-Atlantic states,
triploid hybrids known as Ambystoma platineum (having two sets of Jefferson salamander
chromosomes and one set of blue-spotted salamander chromosomes) have been confirmed
genetically in New Jersey (Schwartz and Golden, 2002) and may exist but are not confirmed in
eastern Pennsylvania (Hulse et al., 2001).
Blue-spotted Salamander (Ambystoma laterale)
INDICATOR SPECIES
Adult Description: Blue-spotted salamanders are 3 to 5.5 inches (7.5 - 14 cm) total length
with bluish white spots and flecks on a purplish-brown, dark gray or black body (Field Guide
1). Blue spots may stand in sharp contrast against the body color or appear rather muted.
Compared to the Jefferson salamander, blue-spotted salamanders are generally smaller, have
larger bluish spots distributed on the sides as well as the back, and have darker pigmentation
around the vent.
Habitat Requirements: Blue-spotted salamanders are fossorial, spending a majority of their
time in deciduous or mixed deciduous-coniferous forests with rotting logs and deep humus.
They also inhabit forested areas above the water level in swamps and marshlands. However,
compared to other ambystomatids, blue-spotted salamanders are more likely to be found
active on the surface during warmer months. They feed primarily at night on earthworms,
slugs, isopods and other arthropods. Breeding occurs in fish-free pools, including seasonal
forest pools, seasonal open-canopy pools, semipermanent pools, wetlands, and ditches.
Reproduction: Mating occurs in water in late winter or early spring, and generally consists of
one to three explosive breeding occasions per year, which are triggered by warm, rainy nights.
Courtship behavior resembles that of the Jefferson salamander and is described in detail by
Storez (1969). Spermatophores of blue-spotted salamanders are about half the size of those
of Jefferson salamanders. Blue-spotted salamander breeding phenology for the mid-Atlantic
region is shown in Fig. 3-2.
Eggs: Females lay eggs singly, in strings of two to four eggs, or, less frequently, as poorly-
defined masses of 2 - 30 eggs, on the pool floor or attached to leaf litter, vegetation, sticks, or
rocks (Field Guide 4). The total number of eggs that a female deposits in a breeding season
ranges from 100-500.
Larvae: Eggs typically hatch about a month after deposition. Larvae are dark brown with
yellow blotches and paired black spots on either side of the tail fin on the back. Each side has a
light elongated stripe, the undersides are unpigmented, and the tail fins are broad and mottled
with black (Field Guide 5). Larvae most likely feed on zooplankton and dipteran larvae
(Petranka 1998). The larval period typically lasts two to three months.
An Introduction to Mid-Atlantic Seasonal Pools
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Juveniles: Just after metamorphosis, juveniJes have yellowish spotting on both their backs and
underbellies. Juvenile blue-spotted salamanders become mature in about two years.
Range: In the mid-Atlantic states, blue-spotted salamanders are confirmed only in northern
New Jersey (Anderson and Giacosie, 1967).
Regional Notes: This species is listed as Endangered in New Jersey. Blue-spotted salamanders
may have a greater tolerance for disturbed areas than Jefferson salamanders, but this tolerance
may make them more susceptible to other threats associated with human development
(Klemens, 1993). In New Jersey, blue-spotted salamanders have experienced high road
mortality and have had lowered reproductive success in degraded pools with poor water
quality (Schwartz and Golden, 2002). Blue-spotted salamanders have declined with the
conversion of hardwood forests to urban and agricultural areas. Jefferson and blue-spotted
salamanders often hybridize when their ranges overlap, which may reduce the population size
of pure diploid blue-spotted salamander populations (Bogart and Klemens, 1997).
Mabee's Salamander (Ambystoma mabeei]
INDICATOR SPECIES
Adult Description: Mabee's salamanders are 3 to 4.8 inches (8 - 12 cm) total length and are
dark brownish gray to black with silvery white or gray flecks mostly on the sides with a few on
the back (Field Guide 1). Mabee's salamanders have a relatively small head and long slender
toes. Their undersides are light gray to grayish brown with scattered light-colored flecks.
Habitat Requirements: Mabee's salamanders are found in pine savanna, wet woods, and
swamp habitats in southeastern Virginia. In the pine savanna, they inhabit burrows at the edges
of bogs and ponds and migrate long distances to forested areas in the non-breeding season
(J.C. Mitchell, pers. comm.). Mabee's salamanders breed in fish-free seasonal pools, including
seasonal forest pools, sinkhole ponds, Carolina bays, semipermanent farm ponds, and cypress-
tupelo ponds in pinewoods (Hardy and Anderson, 1970).
Reproduction: The breeding biology of Mabee's salamanders is not well-studied (Petranka
1998). According to Hardy (1969) breeding occurs from winter to early spring, but according
to Martof et al. (1980) breeding starts as early as late fall; it is also reported to occur between
December and March in Virginia (Fig. 3-2; J.C. Mitchell, pers. comm.).
Eggs: Females attach eggs singly or in loose chains of two to six eggs to leaves, twigs, and debris
on the bottom of shallow pools (Field Guide 4).
Larvae: Hatchlings are 1/3 inch (0.85 cm) total length and have a single yellow stripe on either
side of the body, bushy gills, and a broad dorsal fin that extends onto the back (Field Guide
5). Older larvae are brown to blackish with two cream stripes along the sides of the body that
are often broken; dorsal and ventral fins are heavily mottled. Mabee's salamander larvae from
Virginian populations feed heavily on isopods and amphipods (McCoy and Savitsky, 2004).
Larvae transform in late spring at sizes of about 2 inches (5-6 cm) total length.
Juveniles: Juveniles are initially black or dark gray above with little or no light flecking. Time
to sexual maturation is unknown.
Range: In the mid-Atlantic region, Mabee's salamanders are only found in southeastern
Virginia.
Field Guide to Seasonal Pool Fauna
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Regional Notes: Mabee's salamanders are listed as threatened in Virginia. The range of
the Mabee's salamander was not discovered to extend into Virginia until 1979 (Mitchell
and Hedges, 1980). The Mabee's salamander is one of the least-studied species of mole
salamanders, with many aspects of their biology and natural history unknown (McCoy and
Savitsky, 2004). Larval Mabee's salamanders from Virginian populations were found to have
significantly higher gastric parasitic nematode loads as compared to those from North and
South Carolinian populations (McCoy and Savitsky, 2004). Habitat loss from ditching and
draining of breeding sites and conversion of forests to agricultural lands has presumably
impacted this species (Petranka, 1998).
Mole Salamander (Ambystoma talpoideum)
INDICATOR SPECIES
Adult Description: Mole salamanders are 3 to 4.7 inches (7.5 - 12 cm) total length, and are
stocky with large limbs, short tails, and large heads. Their backs and sides range in color from
light brown to light bluish gray to dark brown or blackish and are speckled with small bluish
white or grayish flecks (Field Guide 1). Their undersides are bluish gray with light flecks.
Habitat Requirements: Mole salamanders live in underground burrows or tunnels in pine
savannas, hardwood forests, floodplain forests, and swamps. In Virginia, mole salamanders
are primarily found in upland and lowland deciduous forests or mixed deciduous-coniferous
forests. Mole salamanders breed in fish-free pools, including seasonal forest pools, seasonal
forested wetland pools, Carolina Bays, and roadside ditches. They are more successful in pools
that do not also support populations of spotted salamanders (Hayslett, 2003).
Reproduction: Breeding typically occurs after long sustained rains and cooler temperatures of
40 - 45° F (Hayslett, 2003). Mole salamanders exhibit a range of migration dates to breeding
pools and breeding season durations that are dependent upon environmental conditions
(Semlitsch, 1985a; Hayslett, 2003). In Virginia, the time spent at breeding pools was found to
extend from mid-October to early May during a wet year and from late-January to early-April
in a dry year (Hayslett, 2003). Males arrive earlier and stay longer at the pools compared to
females (Semlitsch, 1981). Mole salamander breeding phenology for the mid-Atlantic region is
shown in Fig. 3-2.
Eggs: Females lay eggs singly along the pool bottom on leaves, grass, and twigs (Semlitsch
1985a) at depths of 2 - 12 inches (A. Braswell, pers. comm.). Total clutch sizes for a single
female are approximately 200 - 700 eggs, with clutch size and egg size increasing with female
age (Field Guide 4; Semlitsch, 1985a; Hayslett, 2003).
Larvae: Eggs hatch after 30 - 40 days (Semlitsch et al., 1988). Hatchlings have alternating
black and yellow blotches along the midline of the back and on the tail fin. Older larvae
develop two cream or dull yellow stripes on each side that break up toward the tail, as well
as a characteristic dark band that extends along the midline of the belly, which is retained in
juveniles and gilled adults (Field Guide 5).
Juveniles: Larvae may start metamorphosing by mid-June (North Carolina, A. Braswell,
pers. comm.). If larvae have not metamorphosed by mid-July, they may overwinter, become
sexually mature and reproduce as paedomorphs the following spring and then metamorphose
to terrestrial form (Hayslett, 2003; A. Braswell, pers. comm.). This reproductive strategy of
An Introduction to Mid-Atlantic Seasonal Pools
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paedomophosis primarily occurs in pools that do not dry annually (Semlitsch, 1985b). A
paedomorph, or gilled adult, is darker than an immature larva and may be lacking the midline
dark stripe on its belly. Newly transformed juvenile mole salamanders are brownish green in
color. About 2-4 weeks after transformation, adult patterns (gray flecking) begin to appear.
In South Carolina, the majority of mole salamanders become sexually mature in the first year,
within a few months of transformation (Semlitsch et al., 1988).
Range: In the mid-Atlantic region, mole salamanders only occur in south central Virginia in
an area geographically disjunct from the rest of the species' range (Bader and Mitchell, 1982).
Regional Notes: The mole salamander is a species of special concern in Virginia. Loss of
upland forests as well as seasonal and semipermanent pools impacts populations of this
species.
Frogs
For the frog species detailed below, please refer to Field Guide 2 for photographs of adults (p. 41),
Field Guide 4 for photographs of eggs (p. 65), and Field Guide 5 for photographs of larvae (p.
68). General information on the frogs' physical appearance, habitat, and behavior were compiled
from Tyning (1990), Green and Pauley (1987), Hulse et al. (2001), Schwartz and Golden (2002),
and White and White (2002). All sizes given for frogs represent 'snout to vent' lengths (SVL) and
do not include the legs. Lengths are primarily from Conant and Collins (1998) and represent the
range of average SVL of these species; where the literature of the mid-Atlantic region gave different
figures, the widest range of lengths was selected.
Wood Frog (Rana sylvatica)
INDICATOR SPECIES
Adult Description: Wood frogs are 1.4 to 2.8 inches (3.5 - 7 cm) SVL and vary in color from
gray brown to dark brown or reddish-brown with a pale white or cream-colored underbelly
and dark crossbars on the hind legs (Field Guide 2). Two dorsolateral ridges extend along the
sides of the back. Wood frogs have a characteristic dark chocolate brown mask that extends
from the snout across the eyes to a point behind the eardrum (tympanic membrane). Males
are usually darker and smaller than females. Males are dark gray brown and have enlarged
thumbs during the breeding season, while females are usually reddish-brown.
Habitat Requirements: As its common name implies, wood frogs inhabit primarily moist or
lowland deciduous woods. In northern Pennsylvania, wood frogs are also found in hemlock-
northern hardwood-white pine communities (Hulse et al., 2001). Outside of hibernation
and breeding times, wood frogs are active on the forest floor during the day and night if
temperatures exceed 53° F and if humidity is high or it has rained. In winter, wood frogs
hibernate in deciduous forests underneath leaf litter or cover objects or in shallow burrows
rarely below the frostline of the soil, making wood frogs susceptible to freezing conditions.
However, wood frogs can withstand temperatures as low as 20° F before freezing because they
release high levels of glucose into their body fluids from liver glycogen stores, which acts as an
antifreeze agent (cryoprotectant). Wood frogs can also survive up to two weeks of extracellular
freezing at moderate subzero temperatures (Storey and Storey, 1986). Wood frogs breed in fish-
free seasonal and sometimes permanent pools in or adjacent to forests, including vernal pools,
beaver ponds, roadside ditches, canals, and borrow/gravel pits.
Field Guide to Seasonal Pool Fauna
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Reproduction: Wood frogs are the first anurans to breed in the calendar year in most of
the mid-Atlantic region. On a warm, wet evening in late winter or early spring, wood frogs
migrate from their woodland habitats to breeding ponds for an explosive two to seven days of
mating. Males may vocalize in pools for up to three to four weeks, but females are typically in
pools for only one to a few days. Freezing weather may interrupt breeding for a period of time.
At the Patuxent Research Refuge, a 13,000 acre refuge in Maryland, wood frogs may breed at
some seasonal pool sites a week or more before breeding commences at other sites, most likely
a result of variation in temperature and microhabitat. Wood frog breeding phenology for the
mid-Atlantic region is shown in Fig. 3-2.
Eggs: Females deposit one egg mass containing approximately 500 - 1000 eggs on vegetation
or sticks beneath the surface of the water that the male quickly fertilizes (Field Guide 4). At
deposition, wood frog eggs are tightly packed together with no outer surrounding jelly matrix
unifying the mass, giving the mass a bumpy appearance on the water surface. Egg masses have
a diameter of about 2.5 to 4 inches (6.3 - 10 cm). After a week or more, egg masses become
amorphous and harder to count individually and may turn green due to algal growth. Females
usually deposit egg masses in the same general area of a pool every year. In a woodland
setting, this is often on the north side of the pool where the ice melts first; this area receives
the most solar exposure. Eggs are most often laid in large communal oviposition sites or rafts
that help to trap heat and accelerate development. Scale (1982) reported one raft of 963 wood
frog egg masses at a pool in Pennsylvania.
Larvae: Wood frog eggs hatch after two or three weeks. Tadpoles are medium-sized, up to
2 inches (5 cm) in length and are dark brown to blackish with gold flecking (Field Guide
5). Their underbellies are pale iridescent. Eyes are dorsally located just above the sides, not
bulging out on sides laterally like tadpoles in the treefrog (Hylidae) family. Initially, they
attach themselves to their disintegrating egg mass with their sucker-like mouths and graze the
algae growing on its surface. For the remainder of the larval stage, they feed primarily on algae
and detritus (although they may also eat smaller siblings or cohorts) and find refuge in the
leaf litter at the bottom of the pool and in large schools in shallow areas of the pool.
Juveniles: Tadpoles metamorphose into their terrestrial form 60-113 days later, usually
sometime in June and July (Berven, 1988; Tyning, 1990). At metamorphosis, froglets look like
miniature adults. Sexual maturation occurs after one to two years for males and after two to
three years for females (Berven, 1990).
Vocalizations: Male wood frog advertisement calls during the breeding season sound like
duck quacks, repeated one to five times. Males call day and night.
Range: Found throughout the mid-Atlantic region except for southeastern Virginia.
Regional Notes: Wood frogs are protected with limits set on take and collection in Delaware,
New Jersey, and Virginia.
An Introduction to Mid-Atlantic Seasonal Pools
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Eastern Spadefoot (Scaphiopus holbrookii}
INDICATOR SPECIES
Adult Description: Eastern spadefoots are 1.8 - 3 inches (4.4 - 7.6 cm) SVL, short-legged,
and stout. They have bulging eyes, rounded heads and snouts, and smooth skin with scattered
small tubercles (warts). Their backs are olive or brown or gray to black with two irregular
yellow lines running from behind their eyes down the length of their backs meeting at a
midline near the rump (Field Guide 2). Sometimes they have an additional yellowish line
on the side of the body. Their throat and chest are white, except during the breeding season
when males' throats darken. The spadefoot's common name is derived from the dark, horny
growth on the inner sides of each hind foot, which facilitates digging. Unlike almost all North
American frogs, spadefoots have vertical pupils; they also have greenish-yellow irises.
Habitat Requirements: Eastern spadefoots live below ground, burrowing in loose, sandy soils
in river floodplains, woods, meadows, or fields. Breeding occurs in short-hydroperiod seasonal
or ephemeral pools. They are adapted to dry conditions and can survive prolonged droughts,
sometimes for years, lying dormant below the surface. During these dry periods they excrete a
fluid that hardens around their curled-up bodies to prevent desiccation (Tyning, 1990).
Reproduction: On mild afternoons and evenings in the spring (starting as early as February),
summer, or fall, during or just after periods of very heavy rains and low barometric pressure,
spadefoots dig out from their burrows to breed in recently filled seasonal pools or ditches. They
are explosive and unpredictable breeders and may appear by the dozens or even hundreds to
breed following a heavy storm. The male grasps the female in an inguinal amplexus, just above
her hind legs; other species of male frogs in the region grasp females behind the front legs.
During the breeding season, males develop black cornifications on the first three fingers of the
front feet. Eastern spadefoot breeding phenology for the mid-Atlantic region is shown in Fig.
3-2.
Eggs: Eggs are laid and fertilized externally on underwater vegetation. Each female may deposit
up to 2500 eggs in strands or bands that are 1 - 2 inches wide (2.5 - 5 cm) and up to 12 inches
long (30 cm); as the eggs swell with water, they clump into more irregular bunches (Field
Guide 4).
Larvae: Spadefoot eggs hatch very rapidly, after 1 day to one week, depending on water
temperature (Richmond, 1947). Tadpoles are dark bronze to dark brown and have close-set
eyes near the top of their head (Field Guide 5). The tail fins are translucent and are unmarked.
Spadefoot tadpoles spend the first one to four days relatively inactive, attached to their egg
mass or other objects. Then, tadpoles swim throughout the pool (near the water surface if the
pool is deep) feeding on plankton. Between one and two weeks after they hatch, tadpoles form
dense schools, feeding continuously on algae and carrion (Richmond, 1947).
Juveniles: Typically, spadefoots transform into juveniles after about a month (range of two
to ten weeks) of larval development, depending upon water temperature and larval density
(Richmond, 1947; Semlitsch and Caldwell, 1982; Tyning, 1990). Newly transformed eastern
spadefoot juveniles congregate in large numbers around the pool for several days after
metamorphosis (Richmond, 1947). They are active during the day foraging near their natal
ponds. Juveniles reach maturity at about 2 inches (5 cm) at two years of age (Pearson, 1955).
Vocalizations: The advertisement calls of male spadefoots are loud, abrupt grunts or squawks
that sound like a downward-slurred "errrrrrgh," often repeated in rapid succession.
Field Guide to Seasonal Pool Fauna
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Range: Eastern spadefoots are found in lowland areas of the Coastal Plain and some of the
adjacent Piedmont areas, with very scattered distributions in mountainous areas (Martof et al.,
1980; Mitchell and Reay, 1999). They are absent from northwestern Maryland, northwestern
Pennsylvania, northern Virginia and are known from only a few places in West Virginia.
Regional Notes: Eastern spadefoots are on the watch list (special concern without legal
protection) in West Virginia and are protected (with limits set on take and collection) in
Delaware, New Jersey, and Virginia. Eastern spadefoots are rarely seen or heard except after
heavy rain events, undergo rapid development, and spend much of their lifetime underground.
For these reasons, the distribution of this species has not been thoroughly elucidated.
Fairy Shrimp
Crustaceans in the class Branchiopoda include fairy shrimps, tadpole shrimps, clam shrimps,
and water fleas. With the exception of water fleas, which occur ubiquitously in many freshwater
habitats, the Branchiopods are among the most distinctive inhabitants of seasonal pools (Smith,
2001). The primarily freshwater order Anostraca, the fairy shrimp, has 50 documented species in
the United States (Belk, 1975; Smith, 2001). Fairy shrimp in particular have become emblematic of
seasonal pools, and are considered an indicator species group of mid-Atlantic seasonal pools.
Fairy shrimp: Order Anostraca
INDICATOR SPECIES
Adult Description: Fairy shrimp adults range in total length from 0.5 to almost 2 inches
(1.2-5 cm). Their coloration is variable, and may be partially dictated by the food they eat;
they occur in colors of gray, blue, green, orange, and red (Field Guide 3; Smith, 2001). These
crustaceans glide gracefully about the pool swimming upside down with 11 pairs of swimming
legs waving above, filtering their food.
Habitat Requirements: Fairy shrimp feed on microbes and detritus in the water column
or substrate (Smith, 2001). Fairy shrimp tend to do better in seasonal pools with short
hydroperiods (Mahoney et al., 1990). They appear in seasonal pools in late winter or early
spring, completing their life cycle in a short period before predatory insects reach maximum
densities (Wiggins et al., 1980).
Reproduction: Detailed species-specific reproductive biology of most fairy shrimps is not well
known. The following is a general account; there are likely differences among species. During
courtship, male fairy shrimp clasp the female with antennae and they swim together around
the pool for days at a time. After copulation, which only lasts several seconds, eggs are carried
externally in the female's brood sac for one to several days. During this time the eggs undergo
early development. Females lay one to six clutches of eggs per season at two to six day intervals.
Clutch size is 10 - 250 eggs (Smith, 2001). Some fairy shrimp may produce two types of eggs
- thin-shelled eggs that hatch quickly and thick-shelled eggs that are more hardy. The latter of
these two types, the resting (dormant) eggs, allow fairy shrimp to exploit seasonal pools and
to maintain their populations through the dry season of the pools and through freezing winter
conditions. Fairy shrimp eggs are dormant from 6 to 10 months per year in the mid-Atlantic
region before hatching during pool flooding. Not every egg will hatch - eggs may stay viable
buried in the seasonal pool bed sediments for many years. Resting eggs may be transported
in the wind or by birds, insects, or salamanders (Lowcock and Murphy, 1990; Bohonak and
An Introduction to Mid-Atlantic Seasonal Pools
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Whiteman, 1999; Smith, 2001). Metamorphic Ambystoma salamanders may ingest female fairy
shrimp and defecate in another pool, thereby transporting their eggs (Bohonak and Whiteman,
1999).
Range: Four species from two families have been recorded for the mid-Atlantic region: three
species of Eubranchipus in the family Chirocephalidae and one species of Streptocephalus in the
family Streptocephalidae. In addition, another species (Eubranchipus neglectus) may be found
in the mid-Atlantic region, though this is not confirmed (Belk, 1975, Belk et al., 1998).
Regional Notes: There is very little published research on Anostraca of seasonal pools in the
mid-Atlantic region. Additionally, there has been confusion surrounding the records of species
distributions due to mistakes in identifying two species (Belk et al., 1998). Adult fairy shrimp
tend to be unpredictable in occurrence and abundance and exhibit a patchy distribution
across the landscape. They may be sporadic in appearance from one year to the next, or may
be abundant for many successive years, then suddenly disappear. Eggs may remain viable in
the pool bottom for years until hatching. Pools in close proximity to a pool with a particular
species of fairy shrimp may have different species of fairy shrimp or none at all (Smith, 2001).
Family
Chirocephalidae
Chirocephalidae
Chirocephalidae
Chirocephalidae
Streptocephalidae
Scientific Name
Eubranchipus holmanii
Eubranchipus neglectus
Eubranchipus serratus
Eubranchipus vernalis
Streptocephalus sealii
States in the Mid-Atlantic Region
Md., N.J., Pa.,Va.
W. Va.* and southwestern Va.*
Md.,Va.
Del., Md., N.J., Pa.,Va.,W.Va.*
Md., N.J.,Va.
Species of fairy shrimp in the mid-Atlantic region. These species distributions are based on Belk
(1975) and Belk et al. (1998). Belk (1975) created distributions using published records and specimens
from the National Museum of Natural History, Washington, D.C.
* These species have not been recorded from these states, but according to range maps, they may occur there (see
Belketal., 1998).
Field Guide to Seasonal Pool Fauna
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COMPARISON OF EGGS AND LARVAE OF AMPHIBIAN INDICATOR SPECIES
The presence of egg masses and larvae provides evidence of use of the pools by amphibians for
breeding. Depending on the species, eggs may be laid singly, in strings, in sheets, or as discrete
masses. Females may lay eggs individually or in communal areas of pools. Eggs and egg masses
of seasonal pool breeders are usually attached to vegetation or woody debris below the water
surface (with the notable exception of the marbled salamander). Egg masses of species of mole
salamanders are encapsulated by a jelly matrk that ranges in consistency from very firm (spotted
salamanders) to medium-firm (Jefferson salamanders) to soft (blue-spotted salamanders). The
jelly matrix is usually clear, although spotted salamander egg masses may be opaque white due to
the presence of a crystalline protein. Frog egg masses, in contrast, lack this outer jelly matrix and
are less cohesive than mole salamander egg masses. Amphibian egg masses change in appearance
over time in the seasonal pools. They swell in size and become more amorphous as they absorb
water. Also, egg masses may begin to take on a greenish hue caused by the growth of a symbiotic
alga, Oophila amblystomatis, within the jelly matrix. This alga derives nutrients from the jelly
matrk and in turn provides oxygen to the developing embryos (Finder and Friet, 1994).
Mole salamander egg masses can also be distinguished from one another based on characteristics
of the eggs. Spotted salamander eggs exhibit a large distance between the inner envelope and
vitelline membrane, such that the vitelline membrane is much farther from the embryo compared
to those of blue-spotted and Jefferson salamanders (Kenney and Burne, 2001). Photographs and
descriptions are provided to aid in the identification of eggs of indicator species by highlighting
distinctive characteristics (Field Guide 4).
Amphibian larvae are often more difficult to identify to species than the egg masses. Several mole
salamander larvae in particular are difficult to distinguish from one another. Photographs and
descriptions are provided to aid in the identification of larvae of indicator species by highlighting
distinctive characteristics (Field Guide 5).
Egg Structure
Embryo
Vitelline
Membrane
Spotted Salamander Egg
Jefferson or Blue-Spotted
Salamander Egg
Comparison of
relative dimensions
of eggs. Spotted
salamander eggs
(left) exhibit a
larger distance
between the inner
envelope and the
vitelline membrane
as compared
to blue-spotted
and Jefferson
salamander
eggs (right). This
characteristic aids in
field identification of
eggs to the correct
species of mole
salamander.
An Introduction to Mid-Atlantic Seasonal Pools
-------
Field Guide 4. Amphibian eggs in mid-Atlantic seasonal pools.*
SPECIES
DESCRIPTION
LOCATION
Spotted Salamander
# of Eggs per Mass:
Average of 75- 110
(total clutch up to 250)
Clear or opaque white
Globular to oval; very firm
jelly-like matrix
Large distance between inner
envelope and vitelline mem-
brane
Attached to sticks,
stems, aquatic
vegetation; up to 8
- 10 inches or more
below water surface
Marbled Salamander
# of Eggs per Mass:
Laid singly
(total clutch 37-130)
Eggs often appear black due
to clinging dirt
Eggs laid singly in nest
depression; no cohesive
outer envelope, but eggs are
grouped
Eggs have a firm, sticky outer
membrane
Nests located in
dried seasonal
pool beds; scoured
in pool bottom or
located in rodent
burrows, beneath
cover objects, or at
water's edge
Eastern Tiger Salamander
# of Eggs per Mass:
Average of 30 - 60
(total clutch up to 421)
Photo: James W. Petranka
Masses 2 - 2.8 inches
diameter
Globular or oblong; matrix
initially very firm but becomes
very loose
Attached to twigs,
stems, and veg-
etation; in water
greater than 8
inches deep
* Information on amphibian eggs was primarily derived from Bishop (1941), Tyning (1990), Petranka (1998), and Kenney and Burne
(2001).
Field Guide to Seasonal Pool Fauna
-------
Field Guide 4. Amphibian eggs in mid-Atlantic seasonal pools.
SPECIES
DESCRIPTION
LOCATION
Jefferson Salamander
# of Eggs per Mass:
10-75
(total clutch up to 300)
Masses clear and cryptic
Cylindrical on branches
and irregular on grasses;
intermediate firm matrix
Attached to sub-
merged branches
or grasses
Blue-Spotted Salamander
# of Eggs per Mass:
1 -30
(total clutch 100 - 500 eggs)
Masses clear
Eggs laid singly, in strings
of 2 - 4, or in poorly-defined
masses of 2 - 30
Attached to
submerged
branches, stems,
and leaves; 8
- 10 inches below
surface or on pool
floor
Mabee's Salamander
# of Eggs per Mass:
2-6
(total clutch size unknown)
Eggs laid singly or in strings
of 2-6
Attached to leaves,
twigs, and debris in
shallow pools
An Introduction to Mid-Atlantic Seasonal Pools
-------
Field Guide 4. Amphibian eggs in mid-Atlantic seasonal pools.
SPECIES
DESCRIPTION
LOCATION
Mole Salamander
# of Eggs per Mass:
Laid singly
(total clutch approx. 200 - 700)
Eggs are darkly pigmented
on top and white below
Eggs laid singly or in small
loose clusters
Attached to
submerged twigs
and stems in
shallow pools
Wood Frog
# of Eggs per Mass:
500-1000
Masses clear
Globular; no outer jelly matrix;
grape cluster appearance
Often attached to
twigs and stems;
often deposited
communally; look
like lumpy sheets
just below water
surface
Eastern Spadefoot
# of Eggs per Mass:
Up to 2500
Strands or bands 1 - 2
inches wide and up to 12
inches long
Attached to
underwater or
floating vegetation
in shallow pools
Field Guide to Seasonal Pool Fauna
-------
Field Guide 5. Amphibian larvae in mid-Atlantic seasonal pools.*
SPECIES
DESCRIPTION
NOTES
Spotted Salamander
Photos: Solon Morse, RTPI
Hatchlings dull olive; no
markings
Older larvae greenish-yellow
with light ventral surface; no
markings on chin and throat;
tail fin mottled with black
More slender than
blue-spotted larvae;
bushier gills
Marbled Salamander
k *-
Bunnell
Hatchlings light gray,
becoming brown; row of light
spots on sides below limbs
Older larvae light olive to
brown to almost black; pale
spots on head and light
yellow-green blotches on
back and tail; throat and
underside pigmented; row
of light spots on sides below
limbs
Throats darker
than spotted
larvae; largest mole
salamander larvae
in early spring due
to earlier hatching
Eastern Tiger Salamander
Hatchlings gray or yellowish
green; dark bands along
backs; white undersides
Older larvae olive-green
or dark brown with black
markings; light underside;
throats generally lack
pigment
Flattened spade- or
triangular- shaped
toes; all other mole
salamanders have
rounded toes;
larger-sized than
other species of
mole salamander
larvae
* Information on amphibian larvae was primarily derived from Bishop (1941), Tyning (1990), Petranka (1998), and Kenney and Burne (2001).
An Introduction to Mid-Atlantic Seasonal Pools
-------
Field Guide 5. Amphibian larvae in mid-Atlantic seasonal pools.
SPECIES
DESCRIPTION
NOTES
Jefferson Salamander
Larvae olive green to brown;
hints of yellow on sides of
neck, head, dorsal fin
Older larvae grayish with
heavily mottled dorsal fins;
broad heads; long toes;
silvery or white belly
Difficult to distinguish
from other mole
salamander larvae
Blue
-Spotted Salamander
rl. X
I
Photo: Steven M. Roble
Photo: Solon Morse, RTPI
Hatchlings dark brown with a
yellow stripe on each side
Older larvae dark brown with
yellow blotches; paired black
spots on either side of tail fin
on backs; light lateral bands
on sides; unpigmented un-
dersides; broad black-mottled
tail fins
Difficult to distinguish
from other mole
salamander larvae
Mabee's Salamander
Photo: Steven M. Roble
Hatchlings brown with single
yellow stripe on each side of
body
Older larvae brown to
blackish with two cream
stripes along sides; fins
heavily mottled
Only occur in south-
east Va. in the mid-
Atlantic region
Field Guide to Seasonal Pool Fauna
-------
Field Guide 5. Amphibian larvae in mid-Atlantic seasonal pools.
SPECIES
DESCRIPTION
NOTES
Mole Salamander
Hatchlings have black and
yellow blotches on back
midline and tail fin (above)
Older larvae have two
cream stripes on each
side; on undersides there
are single black lines
(below)
Photos: Alvin Braswell
Only occur in south-
central Va. in the
mid-Atlantic region
The alternative
adult form
(paedomorph) is
darker than the
immature larva
Wood Frog
Photo: Solon Morse, RTPI
Hatchlings black
Older larvae dark brown
to blackish with gold fleck-
ing; pale underbellies;
light line along side of
snout where mouth will
later form; side of snout
darker than rest of body
May form large
schools in shallows
Eastern Spadefoot
Dark brown to bronze;
close-set eyes near top of
head; tail fins translucent
Form dense schools
An Introduction to Mid-Atlantic Seasonal Pools
-------
APPENDIX A
TECHNIQUES TO LOCATE SEASONAL POOLS
Locating and mapping seasonal pools should be a conservation priority because an inventory of
seasonal pool distribution and status is currently unavailable in the mid-Atlantic region. Appendix
A gives an overview of techniques that can be used to locate seasonal pools, and points the reader to
sources of additional information.
Step 1: Pre-Identification Techniques
The following methods are considered "pre-identification" techniques because they locate potential
seasonal pools. These potential pools need to be verified to ascertain that they are indeed seasonal
pools (see Step 2).
Aerial Photography
Description: Aerial photography is an unobtrusive method for locating landscape features, such
as potential vernal pools, across a large geographic area (Stone, 1992; Jensen, 2000). Seasonal
pool identification will be easiest if the photograph is taken during a relatively wet year in late fall,
winter, or early spring when deciduous leaves are not on the trees and there is no snow. Larger-
scale photographs are better suited for identifying seasonal pools. For example, photos at a scale of
1:4,800 (or 1 inch = 400 feet) are better than photos at a scale of 1:12,000 (or 1 inch = 1000 ft) for
correctly identifying seasonal pools (Calhoun et al., 2003). Scales of at least 1:12,000 to 1:4,800 are
necessary to identify potential seasonal pools.
Notes: Color infrared (CIR) or black and white film can be used for the aerial photographs (Plate
4-1). CIR is more useful because it highlights the presence of water. On CIR photos, pools appear
black because water absorbs color infrared light, contrasting with lighter-colored vegetated areas
(pink, orange, yellow). Compared to black and white, CIR film provides better differentiation
between tree shadows and small pools, discrimination of depth and permanence of water,
detection of pools under dense canopies, and differentiation of land-cover types (Stone, 1992).
The use of black and white aerial photography, though not as consistent and accurate as CIR, is
also a valuable tool (and significantly less expensive than CIR). On black and white aerials, pools
appear black, though they may also appear in various shades of gray if dominated by vegetation.
Utilizing stereoscopic sets of photographs (viewed with a stereoscope) allows analysis of the
landscape in three-dimensions (Jensen, 2000). This technique greatly improves finding seasonal
pools and depressions (Calhoun, 2003). Stereoscopes used in previous seasonal pool studies
include a 2X pocket stereoscope and a mirror stereoscope (Stone, 1992; Pawlak, 1998). In a
study in Massachusetts, 52% of potential vernal pools identified from 1:4,800 black and white
photographs, using a 2X pocket stereoscope, were determined to fit the physical description
of vernal pools (isolated depressions that hold water for two continuous months) after a field
survey (Stone, 1992). In a study in deciduous forests of Maine, 93% of potential vernal pools
identified from 1:4,800 scale black and white photographs, using panchromatic stereophotos, were
determined to be actual vernal pools after a field survey (Calhoun et al., 2003).
A digital orthophoto quadrangle (DOQ) or quarter-quadrangle (DOQQ) is a computer-generated
image of an aerial photograph which has been orthorectified (i.e., altered so that it has the
geometric properties of a map) to allow accurate measurements of ground distance on the photos.
Appendix A: Techniques to Locate Seasonal Pools
-------
This ensures that the photos can be used with automated mapping and Geographic Information
System (GIS) software along with other digital cartographic data.
Regardless of film types used, having assistance from someone with photo-interpretation training
and experience with local ecology will greatly enhance the success of pre-identification aerial
photography (Stone, 1992).
Challenges: Because seasonal pools are typically small, they may be difficult to identify on
aerial photos (Tiner, 1990; DiMauro and Hunter, 2002). There are challenges to using aerial
photographs: 1) available aerial photographs may be out of date or incomplete and scheduling
a fly-over for new aerial photographs is very costly; 2) pools located under dense coniferous,
deciduous or mixed canopy cover may be very difficult to pick out; 3) shadows of trees can
obscure pools or be mistaken for pools; 4) clusters of conifers on black and white photos often
show up as dark spots that look like pools; and 5) small pools are less likely to be identified
compared to large pools (Stone, 1992; Calhoun et al., 2003).
Additional Resources: Burne (2001) provides detailed guidance on using aerial photographs
to identify potential seasonal pools. Aerial photographs are typically available from federal,
state, or county sources, or off the web (e.g., USGS: http://geography.usgs.gov, USDA: http://
www.nrcs.usda.gov/technical/maps.htmT).
U.S. Geological Survey Topographic Maps
Description: The U.S. Geological Survey (USGS) produces topographic (topo) maps at a 1:24,000
scale (or 1 inch = 2000 feet), commonly known as 7.5-minute quadrangle maps. These maps
utilize contour lines to convey the three-dimensional landscape on a two-dimensional map. Both
natural and man-made features are shown on these maps.
Notes: On topo maps, seasonal pools may be associated with or identified by contours designating
depressions, wet spot symbols, and small ponds. Concentrations of these features indicate
particularly good areas to search for seasonal pools.
Challenges: Because seasonal pools tend to be small in size, only contain water for part of the
year, and may be difficult to assess outside of a wet season, they often do not feature on USGS
topo maps (Williams, 1987).
Additional Resources: Topographic maps can be purchased from outdoor equipment stores and
bookstores or can be ordered from the USGS (http://geography.usgs.gov).
U.S. Fish & Wildlife Service National Wetland Inventory Maps
Description: The U.S. Fish and Wildlife Service began developing a series of topical maps of the
United States' water resources in 1974 as part of a National Wetland Inventory (NWI) based on a
wetland classification system developed by Cowardin et al. (1979) (NWI 2002).
Notes: On NWI maps, areas where seasonal pools are likely to be found can be identified
by looking for: 1) wetlands not connected to streams or lakes, 2) wetland classes that are
hydrologically isolated, including ponds (PUB (palustrine unconsolidated bottom), POW
(palustrine open water)), marshes (PEM (palustrine emergent), PAB (palustrine aquatic bed)), wet
meadows (PEM (palustrine emergent)), shrub swamps (PSS (palustrine scrub shrub)) or forested
wetlands (PFO (palustrine forested)). In some cases, as on the USGS topo maps, large seasonal
pools may be identified on NWI maps as ponds.
70 An Introduction to Mid-Atlantic Seasonal Pools
-------
Challenges: Only forested wetlands greater than approximately 0.5 - 1.2 ha in size and unforested
wetland areas greater than 0.4 ha in size are shown on NWI maps; most seasonal pools are smaller
than these sizes and thus will be difficult to detect (Tiner, 1990; DiMauro and Hunter, 2002;
Tiner, 2003a, b). NWI maps should not be the only source used to locate potential seasonal pools
because they will disproportionately locate the largest pools.
Additional Resources: Full descriptions and definitions of NWI wetland codes (e.g., PFO1A)
can be obtained on the NWI website (http://www.nwi.fws.gov/mapcodes.htm). Many NWI maps
are now available in digital format for public use. A mapping tool called the Wetlands Mapper is
offered by the U.S. Fish and Wildlife Service, which allows the user to produce customized maps
(http://wetlandsfws.er.usgs.gov). Hard copies of NWI maps can be purchased from Cooperator-
Run Distribution Centers (http://wetlands.fws.gov/distribution _ctrs.htm).
Step 2: Verification
Ground-truthing
Description: Ground-truthing (field surveying), the practice of surveying the land on foot, is
essential for validating the presence of a seasonal pool. Ground-truthing is always required to
verify whether what you have identified as a potential seasonal pool using an aerial photograph or
map is indeed a seasonal pool. Additional pools not previously identified using aerial photographs
or maps may be discovered during ground-truthing of potential pools. Ground-truthing can
reveal as many as 25% more pools than identified from aerial photographs alone (Calhoun et al.,
2003). In a study in Massachusetts, 79% of pools discovered in field surveys that were missed from
aerial photographs were within 25 meters of other photo-selected pools (Stone, 1992).
Notes: Once having identified a potential seasonal pool on an aerial photograph, their location
should be transferred onto maps to aid in field location (Stone, 1992). Photo-identified seasonal
pools should be verified in the field early in the process, which can allow the photo-interpreter to
correct or adjust the "search image" or "pool signature" to the conditions of the date and type of
aerial photo used (Stone, 1992).
Alternative Techniques:
Systematic Ground-truthing
Description: Ground-truthing has been used to cover areas systematically.
Notes: Stone (1992) searched 201 m long by 20 m wide strip plots selected from a grid array using
a stratified random design. DiMauro and Hunter (2002) and Calhoun et al. (2003) used 1200
m stratified random transects (500 m one direction, 200 m at 90 degree turn, 500 m at another
90 degree turn) within 1 km2 grid squares to ascertain density and characteristics of pools not
identified on aerial photographs or NWI maps. Because seasonal pools may be clustered in the
landscape, ARMI-NE used an adaptive cluster sampling approach to survey for vernal pools at
National Parks (Delaware Water Gap National Recreation Area, Gettysburg National Historic
Park, Rock Creek Park, Shenandoah National Park) and National Wildlife Refuges (Canaan
Valley, Erie, Great Swamp, Patuxent, Wallkill River) in the mid-Atlantic region. A systematic
grid of points set 500 m apart was established on each Park or Refuge and sets of 20 points were
randomly selected for survey. After navigating to a point, a 50 m2 plot around that point was
searched for seasonal pools. If no pools were found, the surveyor went to the next point. If pools
were found, an adaptive cluster sampling approach was adopted, in which additional 50 m2 plots
adjacent to plots with vernal pools were surveyed, ad infinitum.
Appendix A: Techniques to Locate Seasonal Pools
-------
GIS-Modeling
Description: Several states and studies have used GIS technology to model the locations of vernal
pools across the landscape.
Notes: In New Jersey, the Rutgers University Center for Remote Sensing & Spatial Analysis
is using on-screen digitizing, image processing, and GIS coverages including freshwater
wetlands, soil type, land use-land cover, digital elevation models, and color infrared digital
orthophotography to identify likely areas of vernal pool occurrence. Once areas are identified
using GIS, image interpretation and fieldwork were used to verify actual vernal pool
occurrence in the Highlands, Pinelands, and Delaware Bayshore landscape regions (http://
www.dbcrssa.rutgers.edu/ims/vernal). In Massachusetts, Grant (2005) used modeling approaches
and found that certain landscape features such as land use, surficial geology, and topography
could predict the occurrence of a seasonal pool. Stone (1992) found that the presence and amount
of forest cover surrounding a pool, elevation, and surficial geology (glaciolacustrine lake bottom
deposits) were characteristics useful in identifying areas with a high potential for supporting
seasonal pools with indicator species.
72
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APPENDIX B
TECHNIQUES TO MONITOR SEASONAL POOLS
This appendix outlines techniques that may be used to document a pool's location and to record
what animals are using the pool. As highlighted in this manual, seasonal pools are a valuable
resource, but their distribution is poorly recorded for the mid-Atlantic region. Information on
their distribution and the species they support may be incorporated into a monitoring program
or database. New Jersey currently has the only formal statewide program for seasonal pool
documentation and certification in the mid-Atlantic region; their requirements for documentation
are referred to among the techniques. For precise requirements of the New Jersey Department of
Environmental Protection Land Use Regulation Program "vernal habitat," refer to the Freshwater
Wetlands Vernal Habitat Protocol (http://www.state.nj.us/dep/landuse/forms/vernalpr.doc or http:
//www.state.nj.us/dep/landuse/fww/vernal/index.html).
Documenting the Location of a Seasonal Pool
Note: New Jersey requires 1) a metes and bounds description, aerial photograph, professional
survey, or GPS coordinates; 2) a symbol on a standard map (USGS topo) to show the pool's
location; and 3) a sketch map/written description.
Metes and Bounds Description
Provide written directions for locating the pool; include compass bearings and accurate measured
distances (of 1000 feet or less) from at least two permanent landmarks. Also include distinctive
permanent landmarks along the path of travel.
Aerial Photograph
If an aerial photograph is available on which the seasonal pool is clearly visible, highlight its
location.
GPS Coordinates
Use a global positioning system (GPS) receiver and record UTM (Universal Transverse Mercator)
or latitude and longitude coordinates along with an estimated position error.
Symbol on Standard Map
Mark the pool's location and two permanent landmarks on a photocopy of an 8.5" by 11" section
of a USGS topographical map, a tax assessor's map, or a NWI map. Make sure that the map has all
the information on it (e.g., quadrangle name, map scale) necessary to relocate the pool.
Sketch Map
Draw the pool relative to at least two permanent landmarks; include distances and compass
bearings.
Photograph of the Pool
Take photographs of the pool in its landscape setting to aid relocation of the site and to document
the pool's surroundings and hydroperiod at the time. Note the pool location, day and time of the
photo, and the direction of the photo.
Appendix B: Techniques to Monitor Seasonal Pool
-------
Finding and Documenting Indicator Species
It is difficult to estimate the population sizes of seasonal pool animals. Except during their brief and
weather-dependent breeding seasons, adult pool-breeding amphibians are rarely observed above
ground. During winter, adult amphibians hibernate beneath the leaf litter or in small mammal
burrows, and thus appear absent from the surrounding landscape (Madison, 1997; Faccio, 2003). If
breeding does occur, developing amphibians and invertebrates may be observed in the pool from
late winter until they metamorphose or the pool dries out.
Note: To meet the "required field observations for certifying a vernal habitat" in New Jersey, obligate
(indicator) or facultative species must be either 1) photographed, 2) videotaped, 3) audio recorded
(in the case of frog and toad calling), or 4) described in writing.
Prractices to Prevent Negative Impacts to Pool Inhabitants
Handling of fauna should be avoided unless absolutely necessary for identification and
photodocumentation (Box B-l). Handling amphibians presents challenges. Improper handing
of amphibians may cause skin damage that could lead to secondary infections or may create
bone and muscle injuries (Green, 2001). For detailed information on handling amphibians,
refer to the USGS National Wildlife Health Center's Standard Operating Procedure (http://
www.nwhc.usgs.gov/research/amph_dc/sop_restraint.htmT). Another major concern is the spread
of disease-causing agents such as fungi, bacteria, and viruses between pools or animals. For more
information on practices to prevent the spread of amphibian diseases, refer to The Declining
Amphibian Population Task Force (DAPTF) Fieldwork Code of Practice (http://ventura.fws.gov/
es/protocols/dafta.pdf).
Box B-1
Practices for safely handling and reducing disturbance to amphibians*
Do not disturb nesting or mating animals.
Rather than holding amphibians in your hands after capture, immediately place
them in a zip lock bag or a plastic tub for a short period of time:
• Zip lock bags or plastic tubs must contain enough seasonal pool water to cover the gills
and entire body of larvae.
• Lung-breathing adults should not be submerged and should have access to air as well
as moist or wet areas within bags or tubs.
Avoid injury to animals:
• Do not handle amphibians with hands that have been applied with insect repellent or
moisturizing lotions.
• Wet hands before handling amphibians to minimize damage to their outer protective
layer of skin.
• Never hold or pull a salamander by its tail - it may break off.
• Return animals to their exact place of capture.
• When an animal is removed from beneath an object such as a log or stone, replace the
object first, then release the animal next to it so it can crawl back under.
(Continued)
An Introduction to Mid-Atlantic Seasonal Pools
-------
Avoid spreading disease:
• Wash hands thoroughly before and after handling an animal - especially before
handling an animal from another pool.
• Thoroughly clean and disinfect boots, waders, nets and any other objects introduced
into a pool between sites (remove all mud and debris; use bleach for disinfection).
Do not remove egg masses from the pool or detach them from vegetation:
• They are sensitive to water depth and location.
• The matrix that protects many egg masses may be disturbed with handling,
increasing their susceptibility to predators or disease.
• If eggs do become detached, try to reattach them or situate them at the same depth
and in the same area. Egg masses on the bottom of pools are subject to siltation and
low dissolved oxygen concentrations and are less likely to hatch.
Avoid seining; it causes too much disturbance.
•, 1996; Green, 2001; White and White, 2002; Calhoun, 2003
Evidence of Breeding Indicator Species
A minimum of two visits during daylight hours in the spring is recommended to document
breeding indicator species at a seasonal pool. Visits during mid- and late summer are also
recommended to document larvae and emerging juveniles and to determine whether the pool
retained water long enough for successful population recruitment. Visiting pools at night may be
treacherous and there is a greater chance for inadvertent disturbance to the pools. In general, avoid
unnecessarily walking in or directly around the pool edge. If entering the pool, move slowly and
carefully to avoid disturbing the habitat and animals or dislodging egg masses attached to branches
in the water.
Evidence of seasonal pool use by indicator species includes the egg masses, larvae, and adults
of ambystomatid salamanders, wood frogs, and eastern spadefoots and adult fairy shrimp.
Suggestions for finding these species along with tips for photography are below. Unless required by
a seasonal pool program that will lead to possible protection of the pool, we recommend taking a
'hands-off' approach to documenting the animals (e.g., photographing and identifying egg masses
from the shore of the pool) to minimize impacts to these small ecosystems.
Amphibian Egg Masses: Identifying egg masses is a simple and low-impact way of recognizing
use of the pool by indicator species. Refer to Fig. 3-2 to determine what time of year egg masses
of indicator species are most likely present. Wearing polarized sunglasses increases clarity and
depth of vision beneath the surface of the water. If vegetation is scarce, egg masses, particularly
those of ambystomatid salamanders, may be on the bottom of the pool. Search for egg masses
primarily in water depths less than three feet within three to ten feet of shore around fallen logs,
vegetation or sticks/debris. Distinguish between egg masses of all indicator species in your area
(Field Guide 4). Egg masses are best photographed using a polarizing filter on your camera.
Wood frog egg masses tend to be in large communal rafts in the parts of the pool that receive
the most sunlight and warm up and ice out the earliest.
Amphibian Larvae and Transforming Individuals: Salamander larvae can be easily
distinguished from frog and toad larvae (tadpoles) - salamander larvae have bushy external
gills while tadpoles do not (refer to Field Guide 5). Refer to Fig. 3-2 for what time of year larvae
and transforming individuals of indicator species are most likely to be present. During the day,
Appendix B: Techniques to Monitor Seasonal Pool ^^> 75
-------
salamander larvae tend to hide on the bottom of the pool beneath vegetation and detritus.
Wood frog and eastern spadefoot tadpoles often congregate in schools in shallow parts of the
pool. Dipnets (aquarium dip nets or D-shaped dip nets) or scoops may be used to capture
larvae; once captured, they should be transferred quickly into a water-filled container.
Transformed individuals respire with lungs rather than gills so they should not be submerged
in water. To photograph larvae, keep them in water in a container, place a white background
behind the container, and use a camera with a polarized lens. Ideally, try to get photographs
of larvae from above, the side, and below.
Adult Amphibians: Adult frogs and salamanders are best found by carefully searching
the water's edge and the terrestrial area adjacent to the pool beneath logs, rocks, and other
debris. Wood frogs may be found in the pool itself day or night during the breeding season
when males are calling. In general, it is not necessary to handle these amphibians in order
to identify them. If it is necessary to photograph adults for documentation, follow these
suggestions for handling. Most salamanders in cool spring weather move slowly and can
be caught by hand by gently grasping in the middle of the body between forelimbs and
hindlimbs (Green, 2001). Hold them in your cupped wet hand or place them in a container
with a moist surface (e.g., with wet leaves or shallow water). Frogs, however, will require an
active pursuit, by quickly bringing a cupped hand over them on land or using a dipnet on
land or in water. Hold frogs and toads gently but firmly around the waist with hindlimbs
extended to prevent kicking (Green, 2001). Alternatively, place the frog or toad in a deep
container or a container with a lid (so it can't leap or hop out) with a moist surface on the
bottom. Photograph adults from slightly above and off to one side of the individual and try
to fill the frame of the photo with the animal.
Fairy Shrimp: Adult fairy shrimp tend to be unpredictable in occurrence and their
distribution is not at all well known for the mid-Atlantic region (see Field Guide for the life
history of fairy shimp). Because fairy shrimp are delicate, it is best to catch and examine them
using plastic tubs or bins dipped into the water, letting the water and fairy shrimp flow into
the container. After describing and photographing them, gently release them back to the pool
by submerging the container in the water and letting them swim out. For most purposes,
identifying fairy shrimp as in the Order Anostraca is sufficient. Species identification is
difficult and requires examining a male specimen under a dissecting microscope (see Belk,
1975 and Belk et al., 1998 for identification).
An Introduction to Mid-Atlantic Seasonal Pools
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APPENDIX C
PROGRAMS TO LOCATE, MAP, MONITOR, AND/OR PROTECT SEASONAL
POOLS IN THE MID-ATLANTIC REGION
Appendix C gives an overview of seasonal pool-related projects, initiatives, and programs
occurring in the mid-Atlantic region, including work carried out by nongovernmental
organizations, state and local agencies, and federal agencies. Many universities are also carrying
out related research on pool-breeding amphibians and invertebrates, but are not included in
this summary.
Regional Programs
There are no comprehensive region-wide initiatives to locate, map, or monitor seasonal pools
in the mid-Atlantic. However, efforts sponsored by the USGS span National Parks and National
Wildlife Refuges across the region. The USGS Amphibian Research and Monitoring Initiative-
Northeast region (ARMI-NE) is mapping seasonal pools and monitoring amphibians at the
pools at selected National Parks (Delaware Water Gap National Recreation Area, Gettysburg
National Historic Park, Rock Creek Park, Shenandoah National Park) and National Wildlife
Refuges (Canaan Valley, Erie, Great Swamp, Patuxent, Wallkill River) in the mid-Atlantic
region (see http://www.pwrc.usgs.gov/nearmi for more information). Also, scientists at the
USGS Leetown Science Center (LSC) have mapped all and monitored many seasonal pools in
Delaware Water Gap National Recreation Area.
Mid-Atlantic State and Local Programs
District of Columbia
We are aware of two efforts to locate and map seasonal pools taking place in D.C.
ARMI-NE (see "Regional Programs") has mapped seasonal pools and monitors seasonal
pool-breeding amphibians in Rock Creek Park, a 1755-acre National Park. The Nature
Conservancy has mapped seasonal pools in the Potomac Gorge area of the Chesapeake and
Ohio Canal National Historic Park that traverses both D.C. and Maryland.
Delaware
There has not been a program undertaken at the state level to locate, map, monitor, or
protect seasonal pools in Delaware. However, state wetland maps and GIS data layers show
locations of approximately 1,500 Coastal Plain Ponds (GPP) in Delaware (isolated wetlands
that may be seasonal). Only CPP greater than 0.25 acre are comprehensively included,
but some as small as 0.10 acre may also be included. The coding for CPP wetlands, which
follows a modified National Wetlands Inventory and Cowardin et al. (1979) alpha-numeric
scheme for a given polygon, includes palustrine forested (PFO), palustrine shrub-scrub
(PSS), and palustrine emergent (PEM) categories followed by a "2". Contact staff at the
Delaware Department of Natural Resources and Environmental Control, Division of
Water Resources for more information (see http://www.dnrec.state.de.us/water2000/
DWRStaffl.asp for current staff listing).
Appendix C: Programs to Locate, Map, Monitor, and/or Protect Seasonal Pools
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The Delaware Natural Heritage Program has natural community information about
some CPP, particularly those in Kent and New Castle counties. A report produced by the
Delaware Natural Heritage Program helped to determine criteria used to map CPP on the
state wetland maps (McAvoy and Clancy, 1994).
The Delaware Chapter of The Nature Conservancy (DE TNC) produced a report which
mapped and assessed the conservation status of Delmarva Bays in Delaware (Zankel and
Olivero, 1999; copies of the report are available through the DE TNC). DE TNC used a
more restrictive definition for these wetlands than was used at the state level for CPP.
Maryland
There has not been a program undertaken at the state level to locate, map, monitor,
or protect seasonal pools in Maryland. Wetland geospatial data are available from the
Maryland Department of Natural Resources at the 1:12,000 scale (MD DNR Geospatial
Data from 1988-1995, CIS download from http://dnrweb.dnr.state.md.us/gis/data/
data.asp). Wetland geospatial data include all photo-interpretable wetlands greater or equal
to 0.5 acres (2,023 m2), although some wetlands less than or equal to 3 acres (12,141 m2)
obscured by conifers may have been missed.
Some Nontidal Wetlands of Special State Concern identified by the Maryland Department
of the Environment and the MD DNR are seasonal pools, especially on the lower coastal
plain, but they are not indicated as such on the map (Paula Becker and Scott Smith, pers.
comm.). The state typically only identifies vernal pools that have state-rare, threatened
or endangered species in them and these seasonal pools are in the MD DNR Heritage
Database.
The Montgomery County Department of Environmental Protection (DEP) and the
Maryland-National Capital Park & Planning Commission (M-NCPPC) initiated a vernal
pool mapping program in 2002 to map seasonal pools throughout Montgomery County,
Maryland as part of the Countywide Stream Protection Strategy. DEP is developing a
Biological Monitoring Database.
New Jersey
The New Jersey Department of Environmental Protection's Endangered and Nongame
Species Program established the Vernal Pool Survey Project in 2000. The project's main
objectives are to locate, map, and inventory seasonal pools statewide. Additionally, this
initiative will monitor the pools' amphibian populations utilizing a trained group of
volunteers. Data collected by volunteers is entered into the Department of Environmental
Protection's land use regulatory databases, which are used to guide land use decisions
(Tesauro, 2004).
The Center for Remote Sensing and Spatial Analysis (CRSSA) lab at Rutgers University
is a collaborator in New Jersey's Vernal Pool Survey Project. CRSSA is utilizing CIS data
layers (e.g., soils, wetlands, geology) and various maps (e.g., digital elevation models, color
orthophotography) to find areas where vernal pools are likely to occur. The Center scans
high-resolution orthophotography of these hotspot areas to pinpoint potential vernal pool
locations (see www.dbcrssa.edu/ims/vernal for more information).
An Introduction to Mid-Atlantic Seasonal Pools
-------
Seasonal pools that are already certified in New Jersey are mapped (see http://
www.state.nj.us/dep/landuse/fww/vernal/index.html). Volunteers continue to collect
biological data about seasonal pools in New Jersey using Freshwater Wetlands Vernal
Habitat Protocols (see Appendix B). Volunteer training sessions are held each year; the
schedule is posted on their website.
Pennsylvania
In Pennsylvania, there are multiple ongoing collaborative efforts to learn more about
seasonal pools and the biota they support. The Pennsylvania Department of Conservation
and Natural Resources (DCNR) considers "vernal ponds" as "special habitat." Recently,
a major program was initiated that will lead to a state-wide seasonal pool locating and
monitoring program. The Pennsylvania Game Commission awarded a State Wildlife Grant
to the Western Pennsylvania Conservancy (WPC) (http://www.paconserve.org) to develop a
web-based seasonal pool registry and research program, beginning in the summer of 2005.
This registry program will bring together academic institutions, non-profit organizations,
state and federal agencies, and citizen volunteers to identify, locate, and study seasonal
pools in Pennsylvania. This grant was awarded in response to DCNR's recognition that
vernal pools are integral to the survival of many at-risk species of wildlife, and that the
distribution and abundance of seasonal pools are currently unknown in Pennsylvania.
The Pennsylvania DCNR supports other efforts related to seasonal pool conservation and
management through its Wildlife Resource Conservation Program (WRCP). In 2002,
the WRCP collaborated with DCNR's Bureau of Forestry, The Nature Conservancy, and
the WPC to fund a study constructing a set of biological criteria that would facilitate the
classification and management of different types of seasonal pools in Pennsylvania. Other
research projects include elucidating the population structure of seasonal pool-breeding
amphibians using molecular genetics techniques and investigating the impacts of timber
harvesting on woodland amphibians.
The Upper Susquehanna Coalition (USC), a network of natural resource professionals
from three counties of Pennsylvania and twelve counties of New York that make up
the headwaters of the Susquehanna River, has been extremely active in seasonal pool
conservation. Through funds provided by the U.S. EPA in support of their ephemeral
wetlands/seasonal pool program, USC is mapping pools throughout the upper
Susquehanna watershed with the ultimate goal of mapping 940 pools. Additionally, the
USC developed a seasonal pool assessment form in 2003, which facilitates a major data
collection effort that began in spring of 2004. The seasonal pool assessment form is a GIS
user interface that collects and organizes comprehensive information on the surveyed
vernal pools. Some of this information will be automatically filled in according to location
of data point. Other details recorded by the observer include: pool characteristics, site
location, directions to the pool, area of the pool, surrounding habitat/land-use, water
chemistry, vegetation and fauna data. For more information contact USC (http://www.u-s-
c.org/html/vernalpoolpage.htm).
Appendix C: Programs to Locate, Map, Monitor, and/or Protect Seasonal Pools
-------
Virginia
There has not been a program undertaken at the state level to locate, map, monitor, or
protect seasonal pools in Virginia. There have been exhaustive biological inventories of
several seasonal pool systems, including a detailed description of the Shenandoah sinkhole
pond system in Virginia (Buhlmann et al., 1999). The Grafton Ponds Sinkhole Complex
has also been inventoried and mapped (Rawinski, 1997; Roble, 1998; Roble and Stevenson,
1998), and a comprehensive management plan is in development (Van Alstine et al., 2001).
West Virginia
There has not been a program undertaken at the state level to locate, map, monitor, or
protect seasonal pools in West Virginia.
An Introduction to Mid-Atlantic Seasonal Pools
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APPENDIX D
SOURCES OF ADDITIONAL INFORMATION ON SEASONAL POOLS
Amphibian and Seasonal Pool Field Guides:
Altig, R., R.W. McDiarmid, K.A. Nichols, and P.C. Ustach. 1998. Tadpoles of the United
States and Canada: A Tutorial and Key. Contemporary Herpetology Information Series
1998. Available from http://www.pwrc.usgs.gov/tadpole.
Conant, R. and J.T. Collins. 1998. A Field Guide to Reptiles and Amphibians of Eastern
and Central North America. 3rd Edition, expanded. Houghton Mifflin, Boston.
Green, N.B. and T.K. Pauley. 1987. Amphibians and Reptiles in West Virginia. University
of Pittsburgh Press, Pittsburgh, Pennsylvania.
Hulse, A.C., C.J. McCoy, and EJ. Censky. 2001. Amphibians and Reptiles of Pennsylvania
and the Northeast. Cornell University Press, Ithaca, New York.
Kenney, L.P. and M.R. Burne. 2001. A Field Guide to the Animals of Vernal Pools.
Massachusetts Division of Fisheries & Wildlife and the Vernal Pool Association,
Westborough, Massachusetts.
Petranka, J.W 1998. Salamanders of the United States and Canada. Smithsonian
Institution Press, Washington, D.C.
Tyning, T.F. 1990. A Guide to Amphibians and Reptiles. Stokes Nature Guides. Little,
Brown and Company, Boston.
White, J.F. and A.W White. 2002. Amphibians and Reptiles of Delmarva. Tidewater
Publishers, Centreville, Maryland.
Seasonal Pool Publications:
Biebighauser, T.R. 2002. A Guide to Creating Vernal Ponds. USDA Forest Service.
Available from http://www.fs.fed.us/r8/boone/vernal.pdf.
Calhoun, A.J.K. and M.W Klemens. 2002. Best development practices: Conserving pool-
breeding amphibians in residential and commercial developments in the northeastern
United States. MCA Technical Paper No. 5, Metropolitan Conservation Alliance.
Wildlife Conservation Society, Bronx, New York.
Calhoun, A.J.K. and P. deMaynadier. 2004. Forestry habitat guidelines for vernal pool
wildlife. MCA Technical Paper No. 6, Metropolitan Conservation Alliance. Wildlife
Conservation Society, Bronx, New York.
Colburn, E.A. 2004. Vernal pools: Natural history and conservation. McDonald &
Woodward Publishing Company, Blacksburg, Va.
Williams, D.D. 1987. The Ecology of Temporary Waters. Timber Press, Portland, Oregon.
Appendix D: Sources of Additional Information on Seasonal Pools
-------
Seasonal Pool Educational Programs:
Roger Tory Peterson Institute. Vernal Pool Project: Teacher professional development and
classroom pool surveys (http://vernalpools.rtpi.org).
The Vernal Pool Association. Online resources for teachers and students
(http://www.vernalpool.org).
Vernal Pool Society of Virginia. The Spring Pools Institute: Field courses for adults and
mature youth; Virginia's Disappearing Ponds: Traveling educational outreach
(http://www.lynchburgbiz.com/virginiasvernalpools).
Amphibian Monitoring Programs:
Frogwatch USA, National Wildlife Federation (in partnership with USGS). Long-term,
volunteer-based frog and toad monitoring program (http://www.nwf.org/frogwatchUSA).
North American Amphibian Monitoring Program, Patuxent Wildlife Research Center,
USGS. Collaborative, volunteer-based vocal amphibians monitoring program (http://
www.pwrc.usgs.gov/NAAMP).
An Introduction to Mid-Atlantic Seasonal Pools
-------
GLOSSARY
Acid deposition: Nitric acid or sulfuric acid
pollution that is deposited in wet forms such as
rain and sleet or dry forms including particulates
and gases. Derived from chemical processes that
transform nitrogen oxides and sulfur dioxide
emissions from primarily anthropogenic sources
(e.g., coal burning), although also from natural
sources (e.g., volcanoes).
Aestivate: Refers to an animal that becomes
dormant or torpid during hot summer months.
Amplexus: Copulatory behavior of frogs and toads;
males clasp female partners from behind to fertilize
the females' eggs as they are released.
Annual pool: Seasonal body of water that dries
annually in typical years; they have hydroperiods
from 2 months to 12 months.
Anthropogenic: Created by humans or as a side-
effect of human activities.
Biodiversity: Shorthand for biological diversity; the
variety and variability of life, at the genetic, species,
and ecosystem level.
Bioniass: The weight of total living organisms per
unit of area or of a species' population per unit of
area.
Breeding phenology: Reproductive-related
activities that occur according to season; time frame
in months when eggs, larvae, and metamorphs of
amphibians are present at seasonal pools.
Cloaca: In many vertebrates, the cloaca is the last
part of the digestive tract which receives feces and
urogenital products. In certain invertebrates, the
cloaca is a terminal portion of the digestive tract that
also serves as respiratory, excretory, or reproductive
tract.
Coniferous: Refers to trees that bears seeds in
cones; the wood of these trees is known as softwood.
Crustaceans: Arthropods of the subphylum
Crustacea; predominantly aquatic; characteristic
exoskeleton, segmented body, and jointed limbs.
Examples are crabs, amphipods, and fairy shrimp.
Deciduous: Refers to trees that lose all their leaves
during cold seasons (e.g., fall and winter in the
temperate zone).
Desiccation: Dehydration or the process of drying.
Detritus: Dead organic matter as well as
decomposers such as bacteria and fungi associated
with the dead organic matter.
Dormant: Refers to resting state when invertebrates
and vertebrates undergo periods of reduced
metabolic and respiratory activity.
Dorsal: The upper surface or back of an animal.
Dorsolateral: Pertaining to the back and side of an
animal. Many species of true frogs have dorsolateral
ridges, two ridges that begin at the eye and go all or
partially down the back. Tadpoles of many species
exhibit dorsolateral eyes, in which the eyes are
located on the top but to the side of the head.
Endemic: Exclusively native to or confined to a
certain region.
Ephemeral pool: Temporary body of water formed
by intense periods of precipitation; hydroperiods less
than two months.
Evapotranspiration: The combination of
evaporation and transpiration referring to the total
water loss from vegetative leaf surfaces and from the
soil surface.
Facultative species: Organisms that use seasonal
pools for obtaining food, water, temporary cover, or
breeding, though they can also successfully breed in
other habitats.
Habitat: The physical place, environmental
conditions, and set of resources that a population
(a group of individuals of the same species that are
capable of interacting with each other in a localized
area) utilizes.
Habitat Fragmentation: The process or occurrence
of the breaking of a larger region of habitat into
smaller patches of habitat. For example, a highway
that is constructed through a forest creates forest
fragmentation; the total area of forest, the size of the
forest patches, and the connectedness of the forest
decreases as a consequence.
Herpetofauna: Grouping of animals that is
composed of amphibians and reptiles.
Glossal
-------
Hybrid: Progeny of a cross between two
different species. For example, salamanders with
chromosomes from both Jefferson and blue-spotted
salamanders as a result of interbreeding between
these two species are considered hybrids.
Hydrology: The scientific study of water, including
the occurrence, properties, distribution, circulation
and transport of water.
Hydroperiod: The duration of time when a wetland
or other water body is saturated or covered with
water.
Impervious: Refers to surfaces that do not allow
the penetration of water and prevent precipitation
and other water to infiltrate soils. Impervious
materials include asphalt, concrete, brick and stone;
impervious surfaces include rooftops, parking lots,
roads, and buildings as well as highly compacted
soils in urban areas.
Indicator species: Organisms that depend upon
seasonal pools for optimal breeding conditions.
Invertebrates: Animals lacking a backbone or
vertebrae.
Landscape connectivity: The extent to which the
landscape facilitates wildlife movement.
Landscape: The traits, patterns, and structure
of a specific geographic area (e.g., mountain
range, watershed, state), including its biological
composition, its physical environment, and its
anthropogenic or social patterns.
Land use: The way land is developed and used in
terms of the kinds of anthropogenic activities that
occur (e.g., agricultural areas, industrial areas).
Larva: The immature stage of any animal species.
Larvae are typically very different in body form and
habit from the adults that they metamorphose into.
Life history: The entire progression of changes
that an organism undergoes from inception or
conception to death.
Metamorphosis: The dramatic transformation
from a larva and/or juvenile form to an adult form;
occurs in numerous invertebrates (e.g., insects) and
vertebrates (e.g., amphibians).
Mole salamander: Of the family Ambystomatidae;
this family contains 30 species of salamanders,
seven of which are mid-Atlantic seasonal pool
indicator species. The common name ofAmbystoma
talpoideum, one of these indicator species, is also
'mole salamander.'
Paedomorph: A sexually mature individual
which fails to metamorphose, retaining its larval
morphology; literally means "child-shape" or
"underdeveloped."
Physiological: Relating to the science of the bodily
functions or organic processes (e.g., metabolism,
digestion, reproduction) of an organism.
Semipermanent pool: Body of water that undergoes
seasonal fluctuations in water levels; they do not dry
annually and have hydroperiods of greater than 12
months.
Spermatophore: A packet or "container" of sperm
produced by male animals, which is subsequently
taken up by or placed in or on the body of a
female. Spermatophores are produced by male
Ambystomatid salamanders.
Succession: The gradual change and replacement
over time of one group of species in a community by
other groups or of one set of conditions by another.
Ventral: The under surface or belly of an animal.
Watershed: The area of land from which runoff
of water, sediments, and dissolved materials (e.g.,
nutrients, contaminants) drain into a river, lake,
estuary, or ocean. Watersheds can be viewed at
different scales, from very small (e.g., the area
draining into a small stream) to very large (e.g., the
entire Chesapeake Bay watershed of 64,000 square
miles).
Wetland: Transitional areas where land-based
and water-based ecosystems overlap. Wetlands are
defined for regulatory purposes as "those areas that
are inundated or saturated by surface or ground water
at a frequency and duration sufficient to support,
and that under normal circumstances do support, a
prevalence of vegetation typically adapted for life in
saturated soil conditions. Wetlands generally include
swamps, marshes, bogs, and similar areas." (This
definition is from the U.S. Army Corps of Engineers
Wetlands Delineation Manual and 33 Code of
Federal Regulations 328.3 (b)).
Zooplankton: Small, often microscopic animals
that feed on detritus, phytoplankton, and other
zooplankton and are preyed upon by zooplankton
and other seasonal pool animals.
An Introduction to Mid-Atlantic Seasonal Pools
-------
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