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Landscape Enhancement Options to Reduce Pesticide Contamination in Pollinator Habitats and Increase Forage for Beneficial Insects in Agroecosystems
In the last decade, there have been reports of pollinator decline, including the abundance of wild bees declining by 23%, commercially-managed honey bee colony losses averaging 40% annually, and 15% reduction in the population of monarch butterflies across the midwestern US. Major factors responsible for pollinator health decline include diminishing habitat and exposure to agrochemicals (as reviewed in Chapter 1). To mitigate further losses, recommendations promote pollinator habitats in agricultural, urban, and natural landscapes, however, improperly placed plantings, may unintentionally expose pollinators to agrochemicals. This dissertation examines five landscape enhancement treatments ((A) no enhancement control, (B) irrigated, (C) adjacent pollinator-friendly cover crops, (D) adjacent trees that act as pesticide drift barriers in between habitat and crop field, and (E) with drift barriers and adjacent cover crops) distributed on 17 newly established pollinator habitats and the role they play on mitigating pesticide contamination. In Chapter 2, sticky traps were used to capture neonicotinoid-laden field dust drifting off crop fields during corn planting and residues were compared across treatments to assess the role enhancements play in mitigating pesticide contamination from crop fields and into pollinator habitats. In Chapter 3, a modified method for quantifying air-borne pesticide residues from conventional seed coat treatments was described to better assess exposure risk to foraging pollinators during maize planting. Lastly, in Chapter 4, the abundance and diversity of forbs, insect pollinators, and bees in pollinator habitats were assessed using transect surveys to evaluate the effect enhancement treatments have on promoting plant-pollinator communities. The overall findings in this dissertation indicate that landscape enhancements, such as pollinator habitats adjacent drift barriers, were effective in reducing off-target pesticide contamination. Further, results strongly support that the addition of diverse plants in high crop production areas will attract pollinators into previously devoid areas. However, it also highlights the need for well-designed placement of pollinator habitats in agricultural landscapes that protect these critical resources from unintended pesticide exposure.
Entomology|Soil sciences|Landscape architecture|Environmental management|Wildlife Conservation|Horticulture|Toxicology|Agricultural engineering
Gupta Vakil, Surabhi, "Landscape Enhancement Options to Reduce Pesticide Contamination in Pollinator Habitats and Increase Forage for Beneficial Insects in Agroecosystems" (2020). ETD collection for University of Nebraska - Lincoln. AAI28259452.