Occupancy and Abundance of Pond-Breeding Anurans in Boreal Landscapes

As resource extraction moves north across the globe, wetland ecosystems in Canada are increasingly degraded because of disturbances associated with anthropic activities, including timber harvesting, hydroelectric development, and mining. These activities may particularly affect amphibian species that depend on certain wetland types for breeding, such as peatland and beaver ponds. We assessed the influence of pond and landscape level characteristics on amphibian use of 50 ponds in northern Quebec, Canada in 2018 and 2019. Using acoustic recorders and visual counts, we estimated occupancy of calling males and abundance of metamorphosed individuals and egg masses of three amphibian species: Wood Frogs (Lithobates sylvaticus), Mink Frogs (Lithobates septentrionalis), and Spring Peepers (Pseudacris crucifer). We quantified the influence of variables such as pond type, area, fish presence, acidity, and landscape features on occupancy and abundance. We found no effect of explanatory variables on the probability of occupancy of calling males of the three species. Detection probability of Spring Peeper choruses increased with air temperature. The abundance of Mink Frog metamorphosed individuals decreased with increasing pond area and increased with water pH. Wood Frog reproductive effort, quantified as egg mass abundance, was more than four times greater in beaver ponds than in peatland ponds. Our survey results provide a reference to guide management decisions regarding conservation of amphibian assemblages in increasingly disturbed wetlands of northern Canada.