APPLYING BIODIVERSITY GAP ANALYSIS IN A REGIONAL NATURE-RESERVE DESIGN FOR THE EDGE OF APPALACHIA, OHIO (USA)

A biodiversity gap analysis is a method, now usually employing geograp hic information systems, for identifying deficiencies in existing biod iversity protection. Key principles of gap analysis were applied to a region of southcentral Ohio (U.S.A.) known as The Edge of Appalachia a s part of a detailed, large-scale (1:24,000) nature reserve design pro ject. By combining Landsat thematic mapper imagery with ancillary data (bedrock geology, elevation, slope, aspect, and stream proximity), a rule-based model was developed to differentiate and map the natural pl ant communities present in the 378-km(2) study area. The model was the n used to generate a map depicting the most likely presettlement plant community distributions for the area. These two maps were compared ag ainst the 5273 ha owned and managed by state and local conservation or ganizations. For the current natural plant community distributions, re gional land-protection efforts represented each plant community propor tionally; however, comparison with the presettlement vegetation clearl y identified serious historical losses of several plant community type s. Our results suggest that future land acquisitions should emphasize those plant community types that were once more widespread in the regi on prior to European settlement, a time when natural processes were le ss compromised by human activity. Current and historical plant-communi ty mapping results were combined and evaluated using the ownership par cel as the fundamental mapping unit. From parcel-based desirability ma ps a conservation plan was developed that addressed community deficien cies using a representation target of 25% for each community type, as derived from the modeled presettlement landscape.