Evaluation of an artificial refuge designed to conserve multiple thermophilic aquatic species.

Authors: Darrick S. Weissenfluh, Gene R. Wilde, Cristi R. Baldino

Year: 2010 (xlii)

Abstract

A refuge may consist of natural or artificial habitat and is one tool managers of imperiled aquatic species commonly use to prevent species from becoming extinct. Most refuges are created to conserve a single species and sometimes multiple species of the same taxa. However, in rare situations, refuges are created to conserve multiple species of different taxa. School Springs is located in the Warm Springs Complex (WSC) of Ash Meadows National Wildlife Refuge, Nevada and was modified into an artificial refuge in 1983 to conserve a single endangered fish species, the Warm Springs pupfish, Cyprinodon nevadensis pectoralis. In 2008, the U. S. Fish and Wildlife Service renovated School Springs refuge and made it a multi-species refuge to conserve multiple thermophilic aquatic taxa including C. n. pectoralis and three WSC endemic aquatic invertebrates: the Ash Meadows Warm Springs naucorid Ambrysus relictus, Devils Hole Warm Springs riffle beetle Stenelmis calida calida, and median-gland Nevada springsnail Pyrgulopsis pisteri. School Springs refuge was designed to meet the habitat requirements of all four species so that a self-sustaining population of each species would persist. From 2009-2010, we conducted 28 bimonthly C. n. pectoralis surveys and 15 monthly endemic aquatic invertebrate surveys based on a stratified (habitat) random sampling design. All life stages of C. n. pectoralis utilize pool habitat more than any other habitat type, whereas all three endemic aquatic invertebrates primarily utilize spring-source and riffle habitat in the upper 20 meters of School Springs refuge. As of September 2010, all four species have reproduced and continue to persist in the refuge. Based on these results, design of the School Springs refuge appears to have succeeded in meeting the habitat needs of this diverse assemblage of imperiled aquatic organisms.