Bee communities, pollination, and landscape context in tropical countryside

In my dissertation, I have explored the drivers of biological diversity and ecosystem services in human-dominated landscapes. The bulk of the dissertation (chapters 2-6) relates specifically to bee communities and the pollination services they provide. The first chapter is a database and GIS analysis of the value of agricultural and urban habitats in California for legally protected and non-protected terrestrial vertebrates. I found that agricultural and urban land uses can provide significant habitat value for vertebrates, particularly non-protected species, but that few, if any, species are dependent on such habitats for their survival. The second chapter is a review of the literature relevant to land use change and pollination. I found that many studies in the literature have ignored dynamics going on in matrix habitats, which has diminished the predictive power of these studies. The third chapter considers the effects of distance to forest and pasture management on bee communities in southern Costa Rica, based on fieldwork. I found no effect on bee diversity and abundance of either proximity to forest or land management, but I did find striking differences in bee community composition at the edges of forest (dominated by meliponine bees) compared to open countryside (dominated by exotic Apis). The fourth chapter describes a new species of bee in the genus Neocorynura discovered in the course of fieldwork, with notes on its biology. My fifth chapter covers a model developed to optimize the design of native habitat, integrated in to farms, to provide pollination services for crops. I found that farmers are constrained in their ability to site pollination reservoirs in low-fertility areas; and when considering bee population dynamics, farm design mixes large pollination reservoirs (for population persistence) with smaller, dispersed reservoirs to ensure even pollination services. The sixth chapter, based on fieldwork in southern Costa Rica, investigated the effects of forest fragment size, shape, isolation, and context on bee communities. I found no trends with regard to bee diversity or abundance, but an increasing proportion of meliponine bees (and decreasing proportion of Apis) with increasing forest fragment area and decreasing edge area ratio.