Field surveys and use of a spatially realistic stochastic patch occupancy model to evaluate the conservation status of the northern cavefish, Amblyopsis spelaea DeKay

Faunal surveys were conducted in 41 cave streams in south-central Indiana and north-central Kentucky between June 2002 and November 2003 for the purpose of collecting data on individual population sizes and the geographic range of the northern cavefish, Amblyopsis spelaea. Specific morphometric characteristics and the general physical condition of fish in each population were used to assess the overall health of individual populations. The presence/absence data resulting from the 2002/2003 surveys and historical data collected by other researchers were used to parameterize a model of metapopulation dynamics, the Incidence Function Model. The model was employed to simulate the metapopulation dynamics of the northern cavefish and to identify a subset of populations potentially critical for long-term cavefish persistence. Simulations resulted in a cluster analysis delineating possible sub-groupings of cavefish populations potentially coincident with surface drainage basins. Finally, extinction of individual populations was modeled to determine potential effects of habitat loss on long-term metapopulation persistence.