Where have all the pollinators gone? An analysis of the shifts in climate and phenology that have altered pollinator diversity in the Greater Yellowstone Ecosystem
Date
2023
Authors
Whipple, Sarah E., author
Bowser, Gillian, advisor
Balgopal, Meena, committee member
Halliwell, Philip, committee member
Fisher, Emily, committee member
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Abstract
Pollinators are in peril, facing worldwide decline due to causes such as climate change, habitat fragmentation, phenological mismatches, urbanization, pesticide use, agricultural intensification, and more. In the age of these challenges, prioritizing suitable habitat for species conservation is essential. United States (US) National Parks, in addition to other protected areas nationally and worldwide, act as species refuges for all biodiversity, including pollinators, and more specifically, butterfly and bumble bee species. While data availability is minimal to answer broad questions of pollinator decline, virtual datasets, including citizen science platforms and digitized Natural History Collections (NHCs), provide robust species occurrence snapshots to the state of biodiversity in the parks. This dissertation assessed pollinators, plant-pollinator relationships, and species responses to climate change in Yellowstone and Grand Teton National Parks, two parks within the Rocky Mountain region of the US. In the first chapter, I provide a literature review and my research framework that guided the following studies. In the second chapter, I conducted a meta-analysis to determine what species responses were worldwide to climate change effects. An analysis of the limited bumble bee literature showed species range contractions as well as detrimental plant-phenological shifts occurring worldwide. Although there were more butterfly studies, there was the most agreement found in earlier species emergence patterns, range contractions, and species generalist population responses. In the third chapter, I analyzed digitized data within NHCs, citizen science platforms, and permit-reported data available for the parks from 1900-2021 to understand the systematic data gaps and taxonomic biases present within available datasets. I observed taxonomic biases and varying prominence within data repositories in both parks. However, the rate of available digitized records will continue to evolve and may shift these systematic gaps. In the fourth chapter, I evaluated the climate, phenology, and pollinator species occurrence relationships seen within the parks. I found that starting floral bloom dates and recent bloom anomalies have not shifted significantly, with an average earlier bloom date of three days observed across the parks. The correlations between phenological stages highlighted the negative effect of half-bloomed floral resources on pollinator occurrences in the subalpine and meadow areas of the park, and the positive effect of senesced floral resources on pollinator occurrences both habitat and park wide. Finally, the fifth chapter summarized with lessons learned, including species case studies, and suggestions for additional research efforts. These findings highlight the importance of continued monitoring of pollinator groups within the parks, particularly amongst groups with specialized plant-pollinator relationships, range restrictions, and sensitive generational production – all in which may be vulnerable in the age of a warming, drying western climate. Researchers can use these findings to inform land management and species conservation strategies, to prioritize useable and robust datasets of varying digitized availability for biodiversity questions, and to understand the baseline of pollinator data observed within two protected areas that have experienced minimized effects of other land-use pressures.
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Subject
citizen science
national parks
pollinators
climate change
biodiversity loss
phenology