The Herpetological Journal

pp. 161-166
Authors: Romansic, John M.; Higashi, Elise M.; Diez, Kristin A. & Blaustein, Andrew R.

Abstract: Recent losses of worldwide biodiversity include population declines and extinctions in many amphibian populations. Many factors, including pathogens, are contributing to amphibian population declines. One pathogen, a water mould of the genus Saprolegnia, causes mortality in early life stages of amphibians and may contribute to the declines of specific amphibian populations. Most of our knowledge of how Saprolegnia affects amphibians comes from studies of embryos. The effects of Saprolegnia on post-metamorphic amphibians are poorly known. Therefore, in the laboratory, we investigated the susceptibility of newly-metamorphosed juvenile amphibians to Saprolegnia in four frog species: Bufo boreas (western toad), Pseudacris regilla (Pacific treefrog), Rana aurora (red-legged frog) and R. cascadae (Cascades frog). We found that juvenile R. cascadae exposed to Saprolegnia had greater rates of mortality than unexposed controls. In the other species, survival was also lower in the Saprolegnia treatments compared with controls but these differences were not statistically significant. Combined effects of Saprolegnia in both embryonic and juvenile stages may make the populations of R. cascadae especially vulnerable.

Keywords: METAMORPH, BUFO BOREAS, PSEUDACRIS REGILLA, LIFE HISTORY STAGE, AMPHIBIAN POPULATION DECLINES, RANA AURORA, R. CASCADAE