The relationship between cave biodiversity and available habitat

Aim The goal of this study was to determine the role habitat availability p lays in the distribution of obligate subterranean cave fauna in eastern Nor th America. Location The numbers of stygobites, troglobites and caves in the counties o f the southeastern USA were analysed. Methods The data were characterized by large numbers of zeroes and by spati al clustering of non-zeroes in five regions. Regression and conditional aut oregressive (CAR) models were used to elucidate the patterns and relationsh ips between numbers of species and numbers of caves both locally and region ally. Results Local effects (regions and numbers of caves in counties) accounted for 45% of the variation in troglobite counts (P = < 0.001) and 24% of the variation in stygobite counts (P = < 0.001). Significant spatial autocorrel ation among both stygobites and troglobites (P = < 0.0001) was found as wel l. Conclusion Overall, habitat availability as measured by cave numbers influe nced species richness. Spatial and regional effects also played an importan t role in determining the observed distributions of the subterranean fauna. Terrestrial and aquatic communities showed very different patterns in thei r relationship to habitat and within the different regions.