Home / Environment / eDNA Reveals Fish Impact on Park Amphibians
eDNA Reveals Fish Impact on Park Amphibians
2 Sep
Summary
- Introduced fish, stocked since 1930, altered park lake ecosystems.
- eDNA survey mapped fish and amphibian presence across 117 lakes.
- Some amphibians face threats, while others use refuge habitats.
Introduced fish have significantly altered ecosystems in Olympic National Park's mountain lakes since stocking began in 1930. Researchers recently completed a comprehensive survey of 117 remote lakes, using environmental DNA (eDNA) collected between 2019 and 2021.
The eDNA technique allowed scientists to map the distribution of introduced fish and native amphibians. The survey detected introduced fish in 59 of the lakes, and found that their presence was associated with lower detection rates for some native amphibians.
However, not all amphibian species have disappeared where fish occur; many coexist by using terrestrial areas or temporary wetlands inaccessible to fish. For example, cascades frogs may breed in ephemeral wetlands, offering refuge for their young.
Climate change poses an additional threat, as warming temperatures and declining snowpack make these vital temporary habitats less reliable. This dual pressure from introduced predators and a changing climate complicates conservation efforts.
This park-wide eDNA baseline is essential for tracking future changes and informing decisions on fish removal or other conservation measures to protect native amphibians.
