Compounding evidence suggests a current or impending sixth mass extinction event and pollinator crisis. While several factors contribute to pollinator declines, the most notable driver is habitat loss and degradation. Agricultural grasslands provide crucial habitat for wild and domesticated fauna, regulate water and nutrient cycles, store carbon, and maintain soil stabilization. However, conventional tall fescue pastures, which dominate the southeastern United States, limit pollinator habitat, reduce ecosystem services, and diminish cattle productivity if infected with toxic endophytes. Establishing wildflowers (WFs) and native warm season grasses (NWSGs) into tall fescue pastures has the potential to boost both pollinator ecosystem services and cattle productivity. This study monitored the differences in honey bee colony health, productivity, and pollen foraging behavior between diversified and conventional grazing pastures in south west Virginia. Chapter 1 sought to evaluate the health and productivity of hives within NWSGW+ diversified and conventional grazing systems. Chapter 2 sought to 1) determine whether honey bees used sown wildflower species in diversified pastures as significant sources of pollen, 2) compare species composition and nutritive value of pollen collected from hives within diversified and conventional pasture systems, and 3) evaluate temporal trends in pollen collection. Floral surveys revealed diversified pastures had almost 4x greater mean bloom density than conventional pastures, with over half of all blooms recorded in diversified pastures belonging to unsown species. Results from this study suggest that colonies in diversified pasture systems may have a slight advantage in population resource acquisition, population growth, and winter survival following the first year of establishment, though further research is needed. Pollen DNA metabarcoding revealed that honey bees in both diversified and conventional pasture systems have similar diets, and that sown species were foraged upon primarily in the fall. Samples collected from diversified pasture systems yielded greater pollen weight, species richness, and protein content. In conjunction with previous research, these results indicate that diversified pastures could ultimately provide a more complex nutritional support system for pollinators in grazing agroecosystems. However, individual pasture renovation may not be large enough to yield statistically significant differences in honey bee colony success. / Master of Science / Many studies have suggested that we are currently experiencing or entering a sixth mass extinction event and pollinator crisis. While several factors contribute to pollinator declines, the most notable driver is habitat loss and degradation. Agricultural grasslands provide crucial habitat, regulate water and nutrient cycles, store carbon, and maintain soil stabilization.
However, conventional tall fescue pastures, which dominate the southeastern United States, limit pollinator habitat, reduce ecosystem services, and can diminish cattle productivity. Establishing wildflowers (WFs) and native warm season grasses (NWSGs) into tall fescue pastures has the potential to boost both pollinator and cattle health and productivity. This study monitored the differences in honey bee colony health, productivity, and pollen foraging behavior between pastures diversified with WFs and NWSGs and conventional grazing pastures in south west Virginia. Chapter 1 evaluated the health and productivity of hives within diversified and conventional grazing systems. Chapter 2 sought to 1) determine whether honey bees used sown wildflower species in diversified pastures as significant sources of pollen, 2) compare species types and value of pollen collected from hives within diversified and conventional pasture systems, and 3) evaluate temporal trends in pollen collection. Floral surveys revealed diversified pastures had almost 4x greater mean bloom density than conventional pastures, with over half of all blooms recorded in diversified pastures belonging to species we didn't purposefully plant.
Results from this study suggest that honey bee colonies in diversified pasture systems may have a slight advantage in resource acquisition, population growth, and winter survival following the first year of establishment, though further research is needed. A Pollen DNA analysis revealed that honey bees in both diversified and conventional pasture systems have similar diets, and that they collected pollen and nectar from the flowers we planted primarily in the fall. Honey bee colonies in diversified pastures collected more protein-rich pollen from a wider variety of flowers. These results indicate that diversified pastures could ultimately provide a more complex nutritional support system for pollinators in grazing agroecosystems. However, individual pasture renovation may not be large enough to yield large differences in honey bee colony success.
| Identifer | oai:union.ndltd.org:VTETD/oai:vtechworks.lib.vt.edu:10919/116194 |
| Date | 01 September 2023 |
| Creators | Larcom, Raven Miranda |
| Contributors | Crop and Soil Environmental Sciences, Tracy, Benjamin Franklin, Reid, John Leighton, Wilson, James McKee |
| Publisher | Virginia Tech |
| Source Sets | Virginia Tech Theses and Dissertation |
| Language | English |
| Detected Language | English |
| Type | Thesis |
| Format | ETD, application/pdf |
| Rights | Creative Commons Attribution 4.0 International, http://creativecommons.org/licenses/by/4.0/ |
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