Variation invertebrate communities among three successional stages of aspen-dominated boreal mixedwood forests in Alberta

Vegetation, birds, mammals, and amphibians were surveyed in young, mature, and old aspen-dominated mixedwood forests in Alberta to evaluate both changes in vertebrate communities and patterns of covariation between vertebrate and vegetation communities during the first 150 years of succession. Most vertebrates were observed in all three successional stages, although abundance differed among stages for many species. More than half of the vertebrates were most abundant in old forests, possibly owing to the presence of large live trees, large snags, and abundant down woody materials. For 25% of the vertebrates, abundance was positively related to canopy heterogeneity, indicating that smalt open areas within forests may be important. Conifer-preferring vertebrates were most abundant in areas with many coniferous trees. Patterns of covariation between species and vegetation were similar, but not identical, for bird, mammal, and amphibian communities; bird communities varied more during succession than did mammal and amphibian communities.