Southwest Regional Gap Analysis Project: The Nevada Ecoregional Component

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INTRODUCTION

The Gap Analysis Program (GAP) is a national program of the U.S. Geological Survey (USGS) Biological Resources Discipline that maps the distribution of plant communities and selected animal species and compares these distributions with land stewardship to promote conservation by providing broad geographic information on biological diversity to resource managers, planners, and policy makers who can use the information to make informed decisions. GAP uses satellite imagery and Geographic Information System (GIS) technology to assemble and view large amounts of biological and land management data to identify areas (gaps) where conservation efforts may not be sufficient to maintain diversity of living natural resources.

Historically, GAP has been conducted on an individual state basis. Because of differences among the states in the imagery used for mapping and differences in mapping and modeling protocols, mapped distributions of vegetation types and animals species are often surprisingly inconsistent across state lines. Moreover, the vegetation is not classified the same among the states. In response to these limitations, GAP has embarked on a second-generation effort to conduct the program at a regional scale using 1) a vegetation classification scheme applicable across the U.S.; 2) ecoregional units as the basis for segmenting the landscape into manageable units; and 3) interagency investigator teams with land cover analysis, habitat modeling, and environmental management expertise. The program’s first formalized multi-state regional effort includes the five states ( Arizona, Colorado, Nevada, New Mexico, and Utah) comprising the Southwest Regional Gap Analysis Project (SWReGAP).

NERL-ESD-Las Vegas began leading the Nevada portion of the SWReGAP Project in September 2000. Project responsibilities during the initial year included building a cooperative network, field data acquisition, and providing assistance to the regional laboratory for imagery analysis (RS/GIS Lab at Utah State University). The majority of imagery organization and pre-processing during the first year was completed by the regional lab, based on Landsat 7 TM satellite data (Figure 1) acquired during 1999-2001 by the USGS EROS Data Center (Figure 2). Classification of land cover was conducted by ESD-Las Vegas within individual mapping zones that reflect ecoregional units, many of which extend across state boundaries. Fifteen mapping zones were consolidated into five mega-map zones that lie mostly in Nevada and comprise the responsibility of the Nevada team. Land cover was classified to the "Ecological System" level using the national classification scheme developed by NatureServe. Based on land cover mapping and other data sets, wildlife habitat models were developed and mapped by the SWReGAP investigator group for 819 terrestrial vertebrate species that reside, breed, and use habitat in the 5-state area for a substantial portion of their life history, including important migration stopovers. Approximately 520 species are estimated to occur within the state of Nevada.

BROCHURE

Southwest Regional Gap Analysis Project [PDF Format, 2 pp., 686 KB]

FACT SHEETS

Southwest Regional Gap Analysis Project [PDF Format, 189 KB]
Gap Analysis History and Overview [PDF, 2 pp., 633 KB]

POSTERS

Boykin, K. G., B. C. Thompson, R. A. Deitner, D. Schrupp, D. Bradford, L. O’Brien, C. Drost, S. Propeck-Gray, W. Rieth, K. A. Thomas, W. Kepner, J. Lowry, C. Cross, B. Jones, T. Hamer, C. Mettenbrink, K.J. Oakes, J. Prior-Magee, K. Schulz, J. J.Wynne, C. King, J. Puttere, S. Schrader, and Z. Schwenke. 2007. Predicted Animal Habitat Distributions and Species Richness (PDF) (1 pp., 2.57MB). Chapter 3 in J.S. Prior-Magee, et al., eds. Southwest Regional Gap Analysis Final Report. U.S. Geological Survey, Gap Analysis Program, Moscow, ID.
W.G. Kepner and D.F. Bradford, Plant Communities, Land Ownership, and Topography in Nevada (PDF) (1 pp., 718KB), Southwest Regional Gap Analysis Project.
J. Lowry, R. Ramsey, K. Thomas, D. Schrupp, T. Sajwaj, J. Kirby, E. Waller, S. Schrader, S. Falzarano, L. Langs, G. Manis, C. Wallace, K. Schulz, P. Comer, K. Pohs, W. Rieth, C. Velasquez, B. Wolk, W. Kepner, K. Boykin, L. O'Brien, D. Bradford, B. Thompson, and J. Prior-Magee. 2007. Mapping moderate-scale land-cover over very large geographic areas within a collaborative framework: A case study of the Southwest Regional Gap Analysis Project (SWReGAP). Journal of Remote Sensing of Environment.
William G. Kepner, Todd D. Sajwaj, David F. Bradford, and Edward J. Evanson. 2005. The Nevada Geospatial Data Browser. Presented at the National Gap Analysis Conference and Interagency Symposium, Reno, Nevada. 5-8 December 2005. [PDF Format, 1 pp., 441 KB]

William G. Kepner, David F. Bradford, and Todd D. Sajwaj. 2005. An Inter-agency Approach for Determining Regional Land Cover in the American Southwest: The Southwest Regional Gap Analysis Project. Presented at the EPA Science Forum: Collaborative Science for Environmental Solutions, Washington, D.C., May 16-18, 2005. [PDF Format, 1 pp., 1734 KB]
William G. Kepner, David F. Bradford, and Todd D. Sajwaj. 2004. An Approach for Determining Regional Land Cover and Species Habitat Conservation Status in the American Southwest: the Southwest Regional Gap Analysis Project. Presented at the EPA Open Science Forum, Las Vegas, Nevada, December 9, 2004. [PDF Format, 1 pp., 523 KB]
Todd D. Sajwaj, William G. Kepner, David F. Bradford, and Christine T. Herndon. 2003. Sacrificing the Ecological Resolution at the Altar of Thematic Accuracy: Map Accuracies of Vegetation Classifications in the Eastern Nevada for the Southwest Regional Gap Analysis Project (SWReGAP). Presented at the 13th Annual National GAP Analysis Program Meeting, Fort Collins, Colorado, October 6-9, 2003. [PDF Format, 1 pp., 406 KB]

PROJECT STATUS

Southwest Regional Gap Analysis Program (SWReGAP) for Nevada, Utah, New Mexico, Colorado, and Arizona

TRAINING MANUAL

Field Methodologies and Training Manual for Nevada Field Crews [PDF, 73 pp., 3929 KB]

REFERENCES

John Lowry , William G. Kepner , Kenneth G. Boykin , Kathryn A. Thomas , Donald L. Schrupp , and Pat Comer, Contemporary Digital Land-Cover Mapping for the American Southwest—The Southwest Regional Gap Analysis Project (PDF) (70 pp. 21.85MB) 2008 (pp. 41-42). In Norman, Laura M., Hirsch, Derrick D., and Ward, A. Wesley, eds., Proceedings of a USGS Workshop on facing tomorrow's challenges along the U.S.-Mexico border; monitoring, modeling, and forecasting change within the Arizona-Sonora transboundary watersheds: U.S. Geological Survey Circular 1322, 63 pp.
Prior-Magee, J.S., K.G. Boykin, D.F. Bradford, W.G. Kepner, J.H. Lowry, D.L. Schrupp, K.A. Thomas, and B.C. Thompson, Editors. 2007. Southwest Regional Gap Analysis Project Final Report. U.S. Geological Survey, Gap Analysis Program, Moscow, ID. 422 pp.
Jacobs, S., K. Thomas, and C. Drost. 2001. Mapping land cover and animal species distributions for conservation planning: an overview of the Southwest Regional Gap Analysis Program in Arizona. [PDF, 14 pp., 1.3 MB] pp. 159-172 in van Riper, C., III, K. Thomas, and M. Stuart, editors, Proceedings of the Fifth Biennial Conference of Research on the Colorado Plateau. U.S. Geological Survey/FRESC Report Series USGSFRESC/COPL/2001/24.

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