Stand Structure, Carbon Pools, and Biodiversity Relationships in Temperate Forests of Southern Quebec, Canada: A Multi-Taxon Analysis

Reconciling carbon (C) sequestration with biodiversity conservation remains a key challenge for sustainable forest management, as C–biodiversity relationships vary across taxa and contexts. We evaluated how botanical composition, forest structure, C pools, and land use predict species richness of insects, birds, and bats across mature temperate forests in southern Québec, Canada. Generalized linear models were fitted for insects and birds, while bat data were analyzed descriptively due to low and uneven richness. Botanical composition and forest structure were the most consistent predictors across groups. Insects responded strongly to vegetation structure and C allocation, with richness decreasing with shrub density and mineral soil C but increasing with the soil:above-ground C ratio and distance from infrastructure. Bird richness increased with herbaceous cover and wetland area, emphasizing the value of open and moist habitats. Across taxa, C pools acted as secondary but complementary predictors. Based on observational analyses, our results show that C–biodiversity relationships are compartment-specific and taxon-sensitive, and suggest that maintaining structural complexity, diverse vegetation strata, wetland habitats, and soil C pools may help align biodiversity conservation with C sequestration objectives in temperate forests.