Movement of Imperiled Chiricahua Leopard Frogs during Summer Monsoons

Abstract

Habitat fragmentation and subsequent disruption of animal movement are responsible for extinctions in some species, including amphibians. Amphibians that can travel across fragmented landscapes may be at lower risk of extinction. Chiricahua Leopard Frogs are threatened because of fragmentation associated with habitat loss and degradation. We sought to identify cues leading frogs to leave perennial ponds and factors related to movement ability of Chiricahua Leopard Frogs in New Mexico during the summers of 2013 and 2014. Using pitfall traps, we captured frogs leaving ponds and radio-tracked 30 individuals to characterize overland movements. We checked traps and located frogs daily for up to eight weeks. We assessed factors related to the number of frogs leaving ponds using linear models and to distances moved by frogs using linear mixed models. The number of frogs caught was related to rainfall, but not water temperature, and more frogs were found outside ponds at an intermediate level of rainfall. Frogs who left ponds moved an average of 97 m/ day, but distances were highly variable among individuals. Sex and size did not explain differences in distances moved, after accounting for individual variation. One individual moved 1,658 m in a day and another 9,888 m over 36 days. These distances are farther than recorded previously for this species. Movement data are essential for developing recovery plans for threatened species, and our findings will inform planning by predicting the ability of populations to cope with the effects of habitat fragmentation and the ability of animals to colonize new habitats.