The Conservation Management and Ecology of Northeastern North American Bumble Bees

Bumble bees (Bombus spp.; Apidae) are among the pollinators most in decline globally with a main cause being habitat loss. Habitat requirements for bumble bees are poorly understood presenting a research gap. The purpose of my dissertation is to characterize the habitat of bumble bees at different spatial scales using: a systematic literature review of bumble bee nesting and overwintering habitat globally (Chapter 1); surveys of local and landcover variables for two at-risk bumble bee species (Bombus terricola, and B. pensylvanicus) in southern Ontario (Chapter 2); identification of conservation priority areas for bumble bee species in Canada (Chapter 3); and an analysis of the methodology for locating bumble bee nests using detection dogs (Chapter 4). The main findings were: current literature on bumble bee nesting and overwintering habitat is limited and biased towards the United Kingdom and agricultural habitats (Ch.1). Bumble bees overwinter underground, often on shaded banks or near trees. Nests were mostly underground and found in many landscapes (Ch.1). B. terricola and B. pensylvanicus have distinct habitat characteristics (Ch.2). Landscape predictors explained more variation in the species data than local or floral resources (Ch.2). Among local variables, floral resources were consistently important throughout the season (Ch.2). Most bumble bee conservation priority areas are in western Canada, southern Ontario, southern Quebec and across the Maritimes and are most often located within woody savannas (Ch.3). Climate change is predicted to shift priority areas to more northerly latitudes and to higher elevations (Ch.3). These priority areas do not overlap highly with current protected areas (Ch.3). Using detection dogs to locate the scent of bumble bee nests was more nuanced than expected (Ch.4). The detection distance for nests was short, so dogs needed to conduct detailed searches for nests (Ch.4). Nests may also have multiple entrances which complicates confirming detections made by dogs (Ch.4). The challenges with deploying detection dogs to locate bumble bee nests could be mitigated with careful study design should be carefully considered in future research. This research addresses many gaps in our understanding of bumble bee habitats and will be valuable in informing conservation policy.