United States Environmental Protection Agency	Office of Research and Development

National Exposure Research Laboratory
Research Abstract

Government Performance Results Act (GPRA) Goal #4
Annual Performance Measure #362

Significant Research Findings:

Development of Habitat Models for 71 Vertebrate Species Across Nevada

Scientific	Past national focus on threatened and endangered species has drawn attention to

Problem and	the relatively small number of taxa in the most desperate condition. In contrast,

Policy Issues	directing conservation attention toward maintaining relatively intact biological

systems and communities is proactive, potentially less expensive, and capable of
identifying in advance significant areas for planning.

The Gap Analysis Program (GAP) is a national program of the U.S. Geological
Survey (USGS), Biological Resources Division that maps the distribution of plant
communities and selected animal species and compares these distributions with
land stewardship to identify biotic elements at potential risk of endangerment. To
date, GAP products have been conducted on a per-state basis, and have been
completed for most states. A limitation of this approach, however, has been that
each state has conducted the land cover mapping and vertebrate habitat modeling
in different ways, which has precluded a comprehensive, ecoregional approach to
resource management. To alleviate these limitations, GAP has conducted its first
regional project, the Southwest Regional Gap Analysis Project (SWReGAP),
which encompasses the states of Arizona, New Mexico, Colorado, Utah, and
Nevada. EPA has been a partner in conducting this project, and has had primary
responsibility for the Nevada ecoregional component, including land cover
mapping, land stewardship mapping, and development of 71 of the 833 vertebrate
habitat distribution models represented in the project.

The objective of this Annual Performance Measure was to develop models for
predicted habitat distribution for 71 vertebrate species that reside, breed, or use
habitat in the 5-state region. The range of these 71 species is primarily within
Nevada. These models are based on the concept of wildlife habitat relationships,
defined as a statement describing resources and conditions present in areas where a
species persists and reproduces or otherwise occurs. Knowledge for such
relationships was drawn primarily from published literature, but also from
unpublished sources and expert input in some cases. Data layers represented in the
models included the geographic range (represented by USGS hydrologic units),
SWReGAP land cover data sets, elevation, proximity to various hydrologic
features, topographic features (e.g., slope, landform), and soil characteristics.

Draft models were reviewed internally, and expert review was contributed through
workshops and in individual participation. Each model received formal review
through workshops and/or Web-based protocols by at least one external expert,

Research
Approach


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resulting in over 1,200 reviews by over 80 experts for the 833 species.

Results and	The models and associated metadata are available at

Impact	http://fws-nmcfwru.nmsu.edu/swregap/habitatreview/select_species.htm. These

models provide spatially explicit predictions of habitat for each species that will be
useful to land managers, scientists, and the general public regarding land use
research, policy, planning, and management. Because all the models were
conducted in a similar fashion, and the SWReGAP project as a whole was
conducted in a consistent manner, land managers will have the capability of
assessing the status of biodiversity and evaluating other resources over by far the
largest area within the U.S. No other program provides habitat models for all
vertebrate species inhabiting an area.

The models for the SWReGAP project were completed in collaboration with
groups at New Mexico Cooperative Fish and Wildlife Research Unit (USGS at
New Mexico State University), Utah State University, Colorado Division of
Wildlife, Colorado Plateau Biological Station (USGS), and NatureServe.

Funding to ORD/NERL/ESD was provided from interagency agreement No.
RW14939145 from USGS, Biological Resources Division.

The models and associated metadata are available at:
http://fws-nmcfwru.nmsu.edu/swregap/habitatreview/select_species.htm.

Bradford, D.F., Kepner, W.G., and Sajwaj, T.D. "An Approach for Determining Regional Land
Cover and Vertebrate Species Habitat Distributions in the American Southwest: the Southwest
Regional Gap Analysis Project." Symposium on Scale and Sustainability, Mojave Desert Science
Symposium, Redlands, California, 2004.

Future	A follow-on effort will be conducted to evaluate model accuracy using

Research	independent data sets for selected species and areas in New Mexico and Arizona.

Contacts for Questions and inquiries can be directed to:

Additional

Information	David F. Bradford, Ph.D.

U.S. EPA, Office of Research and Development

National Exposure Research Laboratory

Landscape Ecology Branch

P.O. Box 93478

Las Vegas, NV 89193-3478

Phone: 702/798-2681

E-mail: bradford.david@epa.gov

Funding for this project was through the U.S. Geological Survey, Biological
Resources Division (interagency agreement RW14939145) and the U.S. EPA's
Office of Research and Development, National Exposure Research Laboratory.
The work was conducted by the Environmental Sciences Division.

Research
Collaboration
and Research
Products


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