Native bee communities vary across three prairie ecoregions due to land use, climate, sampling method and bee life history traits

Abstract

Abstract Recent evidence indicates that many native bee species are in decline due to the cumulative effects of multiple human‐induced stressors such as habitat loss, pesticide exposure, pathogens, and climate change. These declines have raised interest in the status of native bees and in developing tools that support management of bee communities and the ecosystem services they deliver. Native bees were surveyed using pan traps and netting over 2 years at 68 locations in croplands and rangelands across three ecological regions of Alberta's prairies – the Grassland, Parkland, and Boreal Natural Regions – to evaluate patterns in bee communities in response to disturbance and ecological gradients. Bee community composition was different across land use and ecoregions. While several cavity‐nesting species had a strong association with rangelands, cavity‐nesting bees tended to be less common in croplands and may be more sensitive to loss of rangeland habitat. Response patterns in overall bee abundance and richness were driven by interactions between region and land use, highlighting the need for regional studies to understand how bee communities respond to these factors. This survey is one of the first to sample the response of bee communities to landscape disturbance across a broad spatial area of the Canadian prairies. Large‐scale compositional studies are essential for understanding the status of native bee communities, and for monitoring long‐term trends over time. We recommend subsequent coordinated surveys using standardised methods across broad spatial scales.