Relationships between trout stocking and amphibians in British Columbia's Southern Interior lakes

Stocking lakes with non-native trout to encourage recreational fishing causes changes in lake ecosystems that can negatively affect biodiversity. I examined associations between rainbow trout (Oncorhynchus mykiss) and amphibians in small lakes of British Columbia’s Southern Interior by comparing abundance, growth, and probability of presence of aquatic breeding amphibians between lakes with and without trout. My evidence suggests that abundance of long-toed salamander (Ambystoma macrodactylum), Columbia spotted frog (Rana luteiventris), and Pacific treefrog (Hyla regilla) larvae may be reduced by 65% or more in lakes with trout. Long-toed salamander larvae were also significantly smaller in lakes with trout. In contrast, western toad (Bufo boreas) larvae were more likely to be present and more abundant in lakes with trout. Managers may reduce negative impacts of introduced trout on amphibians by considering overlap between distributions of trout and amphibians and maintaining some troutless amphibian habitat across landscapes.