Relating resource use to body condition and survival of Ozark hellbenders Cryptobranchus alleganiensis bishopi

Abstract

Endangered species conservation requires the understanding of factors affecting animal condition and performance. However, commonly investigated resource-use metrics such as habitat selection may not accurately predict biological outcomes because some components of habitats are more important to animals than others. We examined individual level resource− outcome relationships and the relationship between 2 biological outcome metrics — body condition and fate — in Ozark hellbenders Cryptobranchus alleganiensis bishopi, which were recently included on the US Endangered Species List by the United States Fish and Wildlife Service. Our regression models included proportional use of a stream substrate, average distance to cover, distance moved, and water temperature as predictors of daily change in body condition or fate of captive-reared, radio-marked released hellbender populations in 2 sections of the North Fork of the White River in Missouri in 2008−2009. Distance moved between observations helped predict change in body condition, but no variable predicted fate well. We infer that resource use of selected substrate features did not predict biological outcomes in the short term. Our results indicate that energetic metrics such as distance moved can predict biological outcomes better than use of substrate features. Body condition did not correlate with fate and may be a poor indicator of an animal’s ability to survive and reproduce. These investigations improve our understanding of influences on biological outcomes in hellbenders, which may improve efficacy of management and conservation of this species through efforts to increase abundance of important resources to improve hellbender condition and performance.