The relationship of amphibian abundance to habitat features across spatial scales in the Boreal Plains

Abstract

We examined the relationship between amphibian abundance and habitat features at 8 spatial scales in boreal Alberta, Canada. Twenty-three local pond variables and 15 landscape variables at 7 scales (50, 100, 200, 500, 1000, 2000, and 5000 m) were incorporated into a Principal Component Analysis (PCA) for each scale. We analyzed amphibian relative abundance against the PC axis scores using regression for each species and each scale. We found that each species' abundance was best described at different spatial scales. Wood frog (Lithobates sylvaticus) abundance was best predicted by local, pond-linked variables, boreal chorus frog (Pseudacris maculata) abundance by 1000-m-scale landscape variables, and western toad (Anaxyrus boreas) by the 100-m scale. We found significant positive relationships with amphibian relative abundance and dissolved oxygen, deciduous forest cover, mixed forest cover, and urban cover. Pond depth, conductivity, total dissolved solids, aquatic plant density, low-shrub cover, and conifer cover showed negative relationships with abundance. We also investigated relationships between landform type and amphibian relative abundance. All 3 species were most abundant on wetlands in the moraine landform. Our research highlights the importance of developing conservation plans based on knowledge of individual species' biology because amphibians do not all respond to the same spatial scale.