Introduction

National Wildlife Refuges are a critical component of the nation's network of preserves for wildlife and biodiversity. The US Fish and Wildlife Service (USFWS), the government agency responsible for managing the refuges, is also responsible for identifying additional critical areas in need of protection under the Refuge system. The biodiversity data sets produced by Gap Analysis, in conjunction with the powerful analytical capabilities of GIS, combine to provide the US Fish and Wildlife Service with an objective tool for identifying parcels of land which meet initial criteria for protection. The USGS Gap Analysis Program (GAP) and the Wyoming Gap Analysis program at the Wyoming Geographic Information Science Center (formerly Spatial Data and Visualization Center) have developed a decision support system, Refuge GAP, that uses GAP and other biological data in a desktop GIS environment (ArcView), to assist USFWS managers in this land prioritization process.

The decision support tool is designed to mirror the U.S. Fish and Wildlife Service's Land Acquisition Priority System for significant community biodiversity targets. This is a four-step process which prompts the user to assign ranks of importance to variables such as significance to biodiversity protection, degree of alteration, management considerations (land use) and species of concern. The user is taken through a series of menus which display data available for input variables and prompts for the input of weights to each of the variables. Once all the variables have been weighted, they are combined in a GIS analytical process, the result of which is a map color-coded to depict areas which meet the specified criteria for land acquisition.

The decision support tool is also designed to report back information on biodiversity elements for specific areas. This project-specific component of the tool allows a regional USFWS office to more efficiently review permit applications for various development and management activities. The user inputs the location of the permit application into the GIS, which then summarizes the number of elements (vertebrate species, land cover types) known or predicted to occur within a specified radius. The tool also provides users with the capability to summarize and view elements by rank, such as neotropical migrants of concern, state species of concern and designated "gap" species. In addition to increasing the efficiency of the review process, the tool can also contribute to cumulative impact analysis at a regional level. The location of each permit review can be recorded into a spatial database, along with the results of the review. This database can then be summarized to assess cumulative impacts as well contribute to the land acquisition prioritization process.