PS 60-155 - Springtime wild bee pollinators of berries in Nova Scotia heathlands

Thursday, August 10, 2017
Exhibit Hall, Oregon Convention Center
Emily Walker, Department of Biology, Saint Mary’s University, Halifax, NS, Canada and Jeremy Lundholm, Department of Biology, Saint Mary's University, Halifax, NS, Canada

Berry-producing plant species often rely on pollination by insects, especially bees, for optimal fruit set. Heathlands in Nova Scotia are dominated by ericaceous species, many of which produce berries that feed wildlife. However, little is known about the abundance and diversity of the bee community active during spring bloom of these key berry-producing species in Nova Scotia, despite their role in providing an important ecosystem service. We describe and compare the community of bees present May-June in coastal, inland, and highland heathlands in Nova Scotia, with a focus on pollinators of berry-producing species and rare species, including Vaccinium uliginosum and Hudsonia ericoides. Bees were netted and pan trapped in all three heathland types, and fruit set of Vaccinium angustifolium (lowbush blueberry), a native constituent of the heathland flora and an economically important regional crop, was monitored in natural and managed environments. We monitored rates of bee visitation and counted flowers and fruit of V. angustifolium at two coastal heaths and two commercial blueberry fields in Nova Scotia.


Spring bee abundance was low at all heathland sites, with no bees captured during many sampling periods. The fewest visits were paid to provincially rare V. uliginosum, a species that occurs only in highland heathlands. We collected fewer social ground-nesting species and more social parasites in highland heathland, suggesting that the harsh summer conditions typical of northern Cape Breton select for bees adapted to shorter summer seasons (solitary ground-nesters) and taxa robust to poor weather (Bombus). Active brooding by queens and mid-June emergence of workers reduced the bumblebee force available to pollinate early blooming plant species, which appear to rely on Andrena, Lasioglossum, and bumblebee queens. Fruit set of V. angustifolium was lower in coastal heathlands than commercial fields, but both environments exhibited fruit set below agricultural targets. Our results suggest that pollination provided by bees may be limited for some spring blooming heathland species, negatively impacting fruit set and likely reducing resource availability for berry-consuming wildlife in heathland habitat. Climate forecasts for Nova Scotia predict increased rainfall in an already rainy, cold, and windy spring season, and our current research focuses on the impact of adverse weather on pollination dynamics in these heathland plant communities.