GAP Analysis Program
A Gap Analysis conducted in Hawaii focused on endangered birds. The distribution of each endangered forest bird species was first plotted individually, based on extensive field inventories. Individual range maps were then combined to obtain a map of species richness for this important group. When compared with a map of the existing reserves, <10% of the ranges of endangered forest birds were protected. Several of the areas of high endangered bird species richness have since been protected by The Nature Conservancy and State and Federal agencies.
This has led to the development of the USGS National Gap Analysis Program, which is a proactive biological characterization program, rather than a crisis-based "let's save the last 10 California Condors" effort, which is very expensive and only affects one species.
Gap Analysis provides a quick overview of the distribution and conservation status of several components of biodiversity. It seeks to identify gaps (i.e., vegetation types and species that are not represented in the network of biodiversity management areas) that may be filled through establishment of new reserves or changes in land-management practices. Gap Analysis uses the distribution of actual vegetation types (mapped from satellite imagery) and vertebrate and butterfly species (plus other taxa, if data are available) as indicators of, or surrogates for, biodiversity. Digital map overlays in a GIS are used to identify individual species, species-rich areas, and vegetation types that are unrepresented or underrepresented in existing biodiversity management areas. Not a substitute for a detailed biological inventory, Gap Analysis organizes existing survey information to identify areas of high biodiversity before they are further degraded. It functions as a preliminary step to the more detailed studies needed to establish actual boundaries for potential biodiversity management areas. Gap Analysis, by focusing on higher levels of biological organization, will be both cheaper and more likely to succeed than conservation programs focused on single species or populations. This methodology is now being used across the world to proactively document the distribution of biodiversity.