Introduction

The Gap Analysis Program (GAP) has two major goals. The first is to provide a regional perspective on the conservation status of native vertebrate species and the land cover types which constitute habitat for assemblages of species, and to make this information available to all who are involved in making decisions about land management. This goal is accomplished by mapping the occurrence of land cover types and predicting the distributions of each native vertebrate species, then overlaying those maps with maps of land management categories, using a computerized Geographic Information System (GIS) to show the conservation status of species and land cover types (Scott et al. 1993, Davis et al. 1990). Analyses are carried out for both states and ecoregions to facilitate natural resource planning efforts in political as well as ecological contexts. The second goal is to build institutional cooperation around the development and application of the information. This maximizes the program's utility by applying both the information and the cooperation gained during the development of the data to the management of our landscape. This report covers the status of the program over the 1994 and 1995 federal government fiscal years (FY 1994-5, from October 1, 1993 to September 30, 1995).

Background

The development of methods for Gap Analysis began in 1987 in response to the need to complement species-by-species management in dealing with broad-spectrum habitat loss (Scott et al. 1987). There was a need for synoptic and geographically explicit information on the distribution of each native vertebrate species, natural community, and their management status. At the time, there were no readily available consistent data that could provide for an understanding of either a single land management decision or the occurrence of a species' habitat in the ecological contexts of landscapes or bioregions.

The term "Gap Analysis" refers to the process by which species and natural communities not adequately represented in conservation lands are identified. These are the "gaps" in our present-day efforts to maintain biological diversity, and it is these that are most likely to become endangered with extinction in the future. By understanding what these gaps are and where they are, future conservation crises and conflicts may be avoided.

To achieve this, Gap Analysis requires computer-based (digital) maps of: (a) existing natural vegetation to the level of dominant or co-dominant species, (b) predicted present-day distributions of native vertebrate species, and (c) public land ownership and private conservation lands. These data layers can then be analyzed, comparing distributions of any native vertebrate species, groups of species, or natural communities of interest with the network of conservation lands. This, then, provides an objective basis of information for local, state, regional, and national options in managing biological resources.

There are many other uses for these data. Most states do not have current maps of land cover, and GAP is the first state- and national-level effort to produce this information at resolutions usable by land managers, planners, scientists, and policy makers.

Maps showing the distributions of land cover, habitat type, vertebrate species, land management, or combinations can then be generated on regional or national bases. The importance of having data sets which are comparable across state boundaries is in revealing actual patterns of species and vegetation community distribution at scales relevant to both the magnitude of present-day changes and the multiple levels of biological organization. Such information may be used to identify areas that are suitable for development and where land use conflicts may be avoided, as well as those areas important for meeting conservation needs.

In the ensuing years since 1988, huge barriers to mapping elements of biological diversity across large areas have been overcome. A wide range of tools for mapping natural land cover and habitat types and predicting vertebrate species distributions has emerged, and procedures have been refined, tested, and further refined. However, some development and testing of methods (for example, accuracy assessment) is still needed. A wide base of consensus and cooperation has been developed, including, for example, the classification of natural communities, a consistent set of satellite images from which to render digital base maps, and ways in which the GAP information is applied to everyday resource decisions and long-range planning.

Structure

Gap Analysis began as a research project under the U.S. Fish and Wildlife Service's (FWS) Cooperative Fish and Wildlife Research Units. The concept was then strongly supported by the FWS Divisions of Research, Refuges, Realty, and Ecological Services. As GAP developed beyond a prototype stage, its status as a basic research project changed. The need to transfer it off the research and development "workbench" and into an inventory and monitoring operation had been recognized by the time the National Biological Service (NBS) was established in November 1993. Under the NBS, GAP was administratively placed in the newly developed Division of Inventory and Monitoring.

The work is carried out on the basis of state-by-state projects, although in four cases a single GAP project covers two or three states. Some states lack cooperative research units, and other institutional arrangements are used (e.g., state natural resources departments and FWS field offices play the lead role in many of these). Each state project is made possible by the mutual commitment of professionals and their organizations in forming a "critical mass" of support and capability. The funding for these projects comes from multiple sources, mostly through the national program to the state projects. However, contributors to state projects include businesses, state universities, state and federal agencies, and non-profit groups. Support is often provided as "in kind" services in the form of agency personnel, equipment, or lab space.

At the national level, the major supporters of GAP are the National Biological Service, the Environmental Protection Agency, and the Department of Defense. Although coordinated by the National Biological Service, GAP is presently made up of over 430 organizations working within 40 state projects.