Validation of occurrence models with emphasis on fish species of greatest conservation need

Stream fishes are among Iowa’s most imperiled animals and a realistic and effective approach to their conservation is needed.  In 2001 the Iowa Wildlife Action Plan identified 68 fish species of greatest conservation need (SGCN).  In 2005, as a product of the Iowa Aquatic Gap Analysis Project (IAGAP), models were created to predict the occurrence of fishes in Iowa’s streams and rivers.  The IAGAP models may prove to be a valuable tool for conservation, but must first be validated with independent data.  Using a prioritized SGCN list, a sub-set of eight focal species was selected for intensive sampling.  Forty-nine stream reaches were sampled in 2009, and sampling will resume during the summer of 2010.  Preliminary analysis showed that IAGAP models performed well for some species while poorly for other. The correct classification rate of the models for the focal species varied from 0.32 to 0.82 and the percent occurrence where species were predicted to occur varied from 0.0% to 83.33%.  Further data collection will increase our understanding of the ability of the IAGAP models to predict the occurrence of rare fishes in Iowa’s wadeable streams.