D3053: The effect of habitat loss due to agricultural expansion on pollinator communities in British Columbia’s at-risk shrubsteppe ecosystem

Habitat loss is playing a significant role in the loss of biodiversity worldwide. The antelope-brush/needle-and-thread grass shrubsteppe, located in BC’s Okanagan Valley, is one of the most biodiverse ecosystems in Canada. However, it is also one of our most at-risk ecosystems, with over 67% of its historic range lost since 1800. One of the primary drivers for this change is agricultural expansion, as conversion of natural habitat to intensive agriculture (ground crops, orchards, and vineyards) has accounted for 79% of the total losses. The Okanagan Valley’s economy relies strongly on its agricultural sector, through the production of crops and the agri-tourism industry. Many crops in the Okanagan rely strongly on animal pollination, and while many farms import European honeybees (Apis mellifera) to manage crop pollination, the presence of native pollinators may significantly increase pollination services provided to crops. Rapid agricultural intensification, habitat loss, and habitat degradation, however, are putting native pollinator species at risk of extinction.

In this study, we evaluate the impact of shrubsteppe habitat loss on pollinator community abundance, diversity, and composition in BC’s Okanagan Valley by surveying a range of shrubsteppe fragments that vary in the amount of surrounding natural habitat. These sample sites range from approximately 10% natural habitat cover (ie. 90% natural habitat loss) to 100% natural habitat cover within a 500m buffer around the site. We hypothesize that the diversity of pollinator species in patches of natural shrubsteppe habitat will decrease in response to increased extent of agriculture around these patches.