Restoration for Wild Bee Community Recovery in the Prairie Pothole Region
Date
2021-05-03
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Abstract
Agricultural intensification is a widespread driver of global pollinator decline, which can subsequently threaten the ecosystem services provided to flowering food crops and wild vegetation species. In North America's Prairie Pothole Region, wetlands surrounded by grassland were once abundant on the landscape, but now generally exist within a matrix of agriculture. I assessed whether restoration of these grassland-wetland complexes from cropland could be used as a tool for mitigating wild bee decline and monitored the development of bee nesting and food resources to establish the mechanisms that drive return to a restored habitat. My objective was to determine if restored communities could resemble a reference state (i.e. remnant grassland-wetland complexes) over a 25-year period. I also observed plant-pollinator interactions and used a model-based approach to determine which plant species supported the highest diversity of wild bees, with the objective of identifying beneficial flowering plants to include in future restorations designed to increase the availability of flowering plants. I found bee diversity increased following restoration and approximated reference sites after 1–4 years. Analyses for bumble bees (Bombus spp.) and other bee species separately demonstrated that the latter group was slower to recover, and resembled reference sites after around 5–10 years. Floral diversity also increased following restoration from cropland but remained slightly lower than reference sites through time. Flower species composition was most important for explaining bee species composition, while time since restoration was comparatively less important. From plant-pollinator interactions, I identified 16 plant species from eight families that supported the highest diversity of bees, including Bombus terricola, a species at risk. In general, Fabaceae species were more popular with bumble bees, while a greater variety of plant families supported non-Bombus bees. My results highlight a potential pathway to improve restoration for wild bee conservation in this region by including specific flowering plants. They also underscore the utility of restored grassland-wetland complexes for providing food and nesting resources to bees within agriculturally dominated landscapes and suggest that restoration can recover wild bee communities to a reference state.
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Keywords
ecological restoration, pollinator conservation, network, wild bees, chronosequence, grassland, wetland, agricultural ecosystem
Citation
Purvis, E. E. N. (2021). Restoration for Wild Bee Community Recovery in the Prairie Pothole Region (Master's thesis, University of Calgary, Calgary, Canada). Retrieved from https://prism.ucalgary.ca.