Bees provide a vital pollination service to many important crops and wildflowers yet are experiencing population declines across European and North American agricultural landscapes. The conservation of bee communities on farmland is a priority of the UK agri-environment schemes, which support pollinators through the provision of natural and semi-natural habitat, foraging resources and nesting sites. Data are needed to evaluate the effectiveness of these interventions in supporting bee communities and to allow the refinement of effective, evidence-based policy. This thesis examines the effectiveness of agri-environment management, though the provision of natural habitat, foraging resources and nesting sites, in supporting solitary bees, an important group of pollinators of which there are 250 species in the UK. Cavity nesting solitary bees and wasps were surveyed on 19 farms situated across central southern England, ranging from farms under no agri-environment scheme, to farms showcasing higher-level agri-environment management. Data on bee and wasp communities was collected by deploying solitary bee nest boxes. These nest boxes are marketed widely as nesting resources for solitary bees and are provided to farmers as part of Higher Level agri-environment schemes. Over the course of the study, 4002 solitary bees and wasps, comprising 10 species, were recorded. Natural Habitat: A positive relationship was identified between the abundance and species richness of bees and wasps and the proportion of natural habitat across farms. The availability of natural habitat also had a positive influence on the structural stability of bee and wasp parasitism networks; a positive association was identified with network link density. Link density measures the mean number of links per species within a network. Higher measures of link density are believed to confer greater resilience to species loss as individuals have more flexibility to switch interaction partner, limiting the risk of a cascade of secondary species extinctions. This set of results is encouraging, suggesting that the natural habitat types being promoted are effective in supporting solitary bee and wasp communities. Foraging resources: Examination of bee foraging preferences, through next generation sequencing of brood cell pollen DNA, demonstrated that the agri-environment scheme sown wildflower mixes do not support the foraging requirements of solitary bees effectively. Of the 15 plants included currently in the wildflower mixes that were recorded as present on the study farms, pollen from only one species, Ranunculus acris, was used by the bees. Rosa canina was identified as the most popular forage plant. The leaves of this species are also a preferred nesting material for Megachile leafcutter bees, providing strong justification for the inclusion of R. canina within the selection of hedgerow plants encouraged by agri-environment schemes. Tripleurospermum inodorum and Trifolium repens were also identified as good candidates for inclusion in wildflower seed mixtures. Nesting sites: A strong positive relationship between the density of solitary bee nest boxes and the rate of brood cell parasitism was identified, indicating that a high local density of nest boxes may expose bee larvae to a higher risk of parasitism. An enhanced risk of larval mortality could counteract the benefit of additional nest site provision. No significant effect of nest box provision on nest box colonization was identified across these study sites, suggesting that their placement across landscapes to encourage more pollinators may be counter-productive. It would be prudent to advise, given the results of this study, for the provision of a small number of dispersed nest boxes, this might more accurately mimic the availability of nesting resources in nature and reduce the risk of enhanced parasitism rates.

The goal of this study was to evaluate several sustainable turf maintenance techniques for their potential to increase beneficial insect populations, which could then provide ecosystem services including pest suppression and pollination. The three techniques in question were 1) raising mowing height in commercial and residential lawns, 2) establishing naturalized roughs on golf courses, and 3) creating pollinator refuges on golf courses through the program Operation Pollinator. We found that raising mowing heights did increase populations of some predators such as spiders and staphylinids, but did not increase predation, which was ubiquitously high because ant populations were unaffected by mowing height. In addition, we found that pests reared in high-mowed grass were less likely to survive and gained weight more slowly than when raised in low-mowed grass. On golf courses, we found that naturalized roughs and traditional roughs supported different populations of predators, but contrary to our original hypothesis, naturalized roughs had little impact on biological control on the rest of the golf course. Operation Pollinator was successful in supporting 49 species of pollinators, including rare and declining bumble bees, demonstrating that turf systems can provide valuable pollinator conservation services, especially in urban systems where pollinator habitats are already rare.

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Public awareness of declining pollinator populations has increased interest in creating “bee–friendly” urban landscapes. I quantified bee visitation and assemblages of 72 species of flowering woody plants common in urban landscapes. I found strong plant species effects and variation in seasonal activity of particular bee taxa but no overall differences in bee visitation or genus diversity between native versus nonnative species or trees versus shrubs. Analysis of pollen from a subset of these plants revealed small but statistically significant differences in total and essential amino acids between native and nonnative species and trees and shrubs, although each group had species with high quality pollen. Uptake and dissipation of soil–applied imidacloprid and dinotefuran was measured in nectar and leaves of two woody plant species, Ilex × attenuata and Clethra alnifolia to assess concentrations to which pollinators might be exposed in landscape settings. Three application timings were evaluated. Residues in nectar and tissue were analyzed by HPLC–MS/MS in two successive years. Residues in nectar following autumn or spring applications exceed concentrations shown to adversely affect individual and colony–level traits of bees. Summer application mitigated concentrations of imidacloprid (8–31 ng/g), but not dinotefuran (235–1191 ng/g), in nectar.

Beekeepers help to secure the pollination capacity of bees by mediating bee-stressors. This study argues that beekeeper strategies are best conceptualized as a series of specialized practices for bettering bee-health, which are mobilized by a variety of actors, including those who are not traditionally considered ‘beekeepers’. The aim of this paper is to explore those human beliefs and practices which are most relevant for gaining insight into the current pollinator problem. Farmers, bee-conservationists, bee-researchers and honeybee-keepers all play an important role in securing bee health. The paper draws on the social-ecological perspective to consider alternative definitions of caring for bees, what shapes these conceptualizations and how these are reflected in beekeeper strategies, which inevitably contribute to the overall functioning of human-bee constituted systems. In the context of rising honeybee colony losses in Canada and of wild bee decline around the world, understanding the diversity of approaches for bettering bee-health is exceedingly important for initiating long-term, sustainable and multi-level bee-pollinator conservation.

Pollinator conservation has recently become a topic of greater interest and research around the world as native insect pollinator species increasingly face population declines. In the United States, growing concerns regarding food security and decreased biodiversity have led to the creation of programmatic and best management practices (BMPs) promotional efforts among governmental and non-governmental organizations. These efforts seek to support pollinators on public and private lands by addressing the primary causes of decline (e.g., habitat loss and increased chemical use). Although these organizations have worked diligently to increase awareness and applicability of programs to private landholders, there is still a gap in pollinator BMP adoption. The purpose of my dissertation was to address the pollinator BMP adoption gap through empirical research with two primary goals: 1) develop and test a measurement instrument to investigate the current state of adoption in Mississippi, landholder attributes, and attribute influence on adoption intentions, and 2) conduct segmentation analyses to develop preliminary recommendations for future educational and outreach efforts to increase adoption of pollinator BMPs. I used two sociological theories to develop a questionnaire consisting of constructs measuring landholder attributes, including Attitudes, Injunctive Norms, Perceived Behavioral Control, Intentions, Knowledge, and Communication Channel Use. I conducted a selfministered mail survey during summer 2018 and received a 38.5% effective response rate. Relative to the first goal, major findings from the research included evidence of reliability and validity for the measurement constructs, landholders having more favorable than unfavorable Attitudes regarding the use of pollinator BMPs on their properties, and Perceived Behavioral Control as the strongest influence on adoption intentions compared to additional landholder attributes. Relative to the second goal, major findings included the generation of four distinct clusters and three land use type segments that allowed for group comparisons and development of a recommended two-step targeted educational and outreach approach. My dissertation provided theoretical and substantive advances to the fields of adoption research and pollinator conservation from which future research and outreach efforts can grow.

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