A Gap Analysis consists of mapping three data layers — land cover, predicted distributions of vertebrate species, and a stewardship layer depicting both location and conservation status of protected areas. This data is then assessed to determine how much of a target species’ (plant or animal) habitat is in conserved areas. From this assessment, planning decisions can be made about whether further protection is merited.
The process breaks down to three parts:
Map the LAND COVER of the dominant ecological systems
Map and model SPECIES ranges and distributions
Map land STEWARDSHIP by mapping both location and conservation status of protected areas
Conduct an ANALYSIS
Gap Analysis is a U.S. Geological Survey/Biological Resources Division (USGS/BRD) research effort being implemented across the nation with the help of over 400 cooperating organizations including private business corporations, non-profit groups, universities and other government agencies. The effort seeks to identify the degree to which all native plant and animal species and natural communities are or are not represented in our present-day mix of conservation lands. Species-rich areas, vertebrate species and land cover types that are not adequately managed for the long-term maintenance of native species and natural ecosystems constitute conservation "gaps."
The Nebraska Gap Analysis Project was prepared by Dr. James W. Merchant (CALMIT) and Dr. Geoff Henebry, then with the Conservation and Survey Division, University of Nebraska-Lincoln, currently Co-Director of the Geospatial Sciences Center of Excellence, South Dakota State University. The project involved close collaboration with the Nebraska Game and Parks Commission, the University of Nebraska State Museum, other university faculty, state and federal agencies and many others. Nebraska GAP objectives were to:
- map existing statewide vegetation and other land cover;
- predict the present distributions of native animal species;
- determine the extent and importance of places of native species richness;
- compare the distributions of vegetation communities with existing land management goals;
- compare places of species richness with existing land management goals;
- provide an objective basis for a statewide biodiversity management strategy.
The Nebraska GAP product includes analyses of the distribution of actual natural vegetation, mapped from satellite imagery and other records, and the distributions of native animal species, mapped by using museum and agency records in conjunction with known habitat ranges. Maps of species-rich areas, individual species of concern, and vegetation types are overlaid on maps of public land ownership and management to provide land stewards with information to make well-informed decisions regarding biodiversity management.