Theses and Dissertations at Montana State University (MSU)
Permanent URI for this collectionhttps://scholarworks.montana.edu/handle/1/733
Browse
2 results
Search Results
Item Pollinator conservation and restoration in semi-natural ecosystems(Montana State University - Bozeman, College of Letters & Science, 2022) Glenny, William Robb; Chairperson, Graduate Committee: Laura Burkle; This is a manuscript style paper that includes co-authored chapters.Semi-natural ecosystems are areas with biological and physical characteristics that resemble natural ecosystems but are also affected by anthropogenic disturbances. Semi-natural ecosystems are also areas with high insect pollinator diversity. Land management actions within semi-natural ecosystems may therefore be important to counteract future declines of insect pollinators. However, current restoration strategies for insect pollinator communities are based on evidence from agricultural ecosystems, which have frequent human interventions to ensure plant success, neglect the importance of nesting materials, and primarily benefit generalist species. To inform management actions for the conservation and restoration of insect pollinators in semi- natural ecosystems, I (1) synthesized the current understanding of the effects of common land management actions on insect pollinators on public lands in the US, (2) identified habitat characteristics which structure the taxonomic and functional diversity of bee communities, (3) evaluated the strength of influence of mechanisms associated with diet breadth across groups of bee species and (4) designed a conceptual model which can be used to select flowering plant species to provide food resources for bee communities in semi-natural ecosystems. Management actions that increase the abundance of floral and nesting resources to support bee species from different functional groups are required to conserve and restore insect pollinator communities in semi-natural ecosystems. I found that (1) management actions have positive, neutral, and negative effects on insect pollinators, but research trends vary depending on the taxon and habitat type, (2) the taxonomic and functional diversity of bee communities are structured by the abundance of both floral and nesting resources, (3) patterns of abundance across space and time have a more positive effect on the diet breadth of bumble bee species compared to non- bumble bee species, and (4) wildflower species that receive a high visitation rate and richness, occupy functionally important positions within bee-flower interaction networks, and are spatially and temporally widespread are important to provide bee communities with food resources in semi-natural ecosystems. These wildflower species may be particularly important to include within seed mixes to revegetate semi-natural ecosystems and provide food resources for insect pollinators.Item Evaluating the effects of climate change and pathogens on pollinator health using plant functional traits and longitudinal monitoring(Montana State University - Bozeman, College of Letters & Science, 2017) Glenny, William Robb; Chairperson, Graduate Committee: Laura Burkle; Michelle Flenniken (co-chair)Pollinators are essential for the maintenance of biodiversity, ecosystem function, and economic productivity. In particular, bee pollinators are required for plant reproduction and pollination of agricultural crops. However, land use change, climate change, pathogens, pesticide exposure, among other factors likely act alone and in combination to negatively impact bee pollinators and the services they provide. Further resolution of the effects of these stressors, both individually and combined, on bee pollinators is important to understand the global decline of pollinator health. Abiotic conditions associated with climate change may alter plant traits important for pollinator attraction leading to in shifts in plant-pollinator communities. Floral visual and chemical traits were measured in four species of forbs subjected to elevated or ambient concentrations of carbon dioxide, and decreased or normal water availability in a fully factorial crossed design. Treated plants were observed for pollinator visitation rates and community composition to better understand the mechanisms by which climate change can influence pollinator attraction. Results indicate that changes in both visual and chemical cues of plants will alter plant-pollinator interactions. Furthermore, plant functional trait responses to climate change increase competition for pollinators in forbs with overlapping flower types, while facilitating pollinator visitation to forbs with dissimilar flower types. Pathogens contribute to annual honey bee colony losses and the declining populations of some wild bee species. Bee pathogens, including viruses, fungi, microparasites and ectoparasites, can vary across geographic location and season. To examine the impact of pathogens on honey bee colony health, using colony size as a proxy for health, we longitudinally monitored pathogen prevalence and abundance of pathogens in honey bee colonies involved in California almond pollination. Individual honey bee associated pathogens varied throughout the one year monitoring period, but Deformed wing virus in parallel with increasing levels of Varroa destructor mite infestation predominated shifts in honey bee pathogen profiles by the end of the sampling period. Our results indicate that bee populations experience multiple concurrent threats operating at multiple scales to affect pollinator health. Continued investigation into factors affecting pollinator health both independently and in concert are needed to develop strategies mitigating declines in pollination services.