What is Gap Analysis?


Gap Analysis is a broad-scale conservation evaluation method that uses GIS technology to assess the status of biodiversity. Three primary data layers are combined in an overlay analysis to identify "gaps" in biodiversity protection.

A data layer of vertebrate distributions is refined into detailed maps of predicted species occurrence by using habitat models to extract areas of suitable habitat from a land cover map. This land cover map constitutes the second data layer, and generally consists of vegetation types and other cover types delineated from Thematic Mapper satellite imagery. Predicted species occurrences can be combined to create maps of species richness for all species, for specific taxa, or for groups of special concern (e.g., endangered species). These predictions of species richness can then be compared to the third primary data layer: a map of conservation lands. Biodiversity hot-spots that are not currently protected within the network of conservation lands would be high-priority areas for establishment of preserves or changes in land management pratices.

Gap Analysis at the UVM Spatial Analysis Laboratory

The nation-wide Gap Analysis effort is being conducted on a state or regional basis. The Vermont Cooperative Fish and Wildlife Research Unit is one of several cooperators in New England GAP. The regional GAP effort in New England has recently been broken up into smaller regions, although cooperation between the New England regions and neighboring states continues. Our primary responsibility here at the University of Vermont had been development of species range maps and species-habitat models. More recently, our involvement in Gap Analysis has shifted to focus on production of a land cover map for Vermont and New Hampshire, and development of a conservation lands database for Vermont.

More detailed information about Gap Analysis at the Spatial Analysis Lab is available on our "Currents Projects" page. See the Gap Analysis homepage to find out more about the National effort.

       Updated: 28 June 2000