Variation in Bumble Bee Foraging Networks Across A Gradient of Forest Canopy
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Date
2024-06
Authors
Metzger, Sam
Journal Title
Journal ISSN
Volume Title
Publisher
University of Oregon
Abstract
Land use change, invasion of non-native species, and other modes of habitat loss contribute to
native bee population declines. A key contribution to population decline may be a loss of
nutritional resources, which can occur when landscapes have reduced floral diversity and
abundance. Increasing floral resources may mitigate future declines and forest ecosystems may
offer necessary food and nesting opportunities for native bees. However, it is unclear whether
and how forest management practices influence the capacity of forests to fulfill these roles. Our
research advances the field's understanding of bumble bee nutrition as a function of plant
community structure by examining it within a forest ecosystem. To do this, we focused on
foraging patterns of bumble bees across a gradient of canopy openness in the Oregon Coast
Range. With the understanding that bumble bees prefer warm, sunny, fair-weathered spaces with
abundant floral resources, we hypothesized (1) there would be a positive relationship between
floral diet breadth and canopy openness. We further predicted (2) increased canopy cover would
result in less floral richness, and greater niche overlap among bumble bee species. Our results
support the first hypothesis for two of our most abundant species but not the third. Moreover,
floral richness was indeed lower with greater canopy cover, but responses in niche overlap varied
across our three most abundant species. This demonstrates that different bumble bees have
varying responses in foraging behavior to forest canopy structure. This research provides
information that could assist in conifer forest management practices to better provide for wild
bumble bee community restoration and conservation.
Description
16 pages
Keywords
bumble bee, population decline, habitat loss, tree canopies