Land conversion and agricultural intensification reduce both on-farm and near-farm non-crop habitat for arthropod biodiversity, with potentially detrimental consequences for biological control of crop pests. The diversity of ichneumonid wasps, a large family of parasitoids, was sampled over three years and parasitism of two insect pests was measured in annual vegetable farms the following year; management practices were described and vegetation and landuse cover within 1.5Km were measured for each farm. Ichneumonidae species richness was positively associated with landscape-scale vegetative cover and field-scale crop diversity, but not with landscape-scale vegetation diversity; subfamily responses to both landscape vegetation classes and crop diversity varied. Species richness within Campopleginae and Cryptinae were positively associated with perennial vegetation and negatively associated with annual cropland, whereas diplazontine richness was positively associated with grasslands and negatively associated with freshwater. Baccharis shrubs and annual crop cover best explain the distribution of ichneumonid species, regardless of subfamily. Three ichneumonid and two braconid wasp species and tachinid flies parasitized Trichoplusia ni larvae, but major mortality was due to Hyposoter exiguae (Ichneumonidae) in May and Microplitis alaskensis (Braconidae) in September. Spring parasitism rates were positively associated with annual crop and grassland cover--an opposite pattern to the abundance and species richness of the Ichneumonidae samples. T. ni parasitism in fall was positively associated with grassland cover, pest control intensity, and decreasing tillage, not perennial vegetation cover. Parasitism of Brevicoryne brassicae was not associated with landscape vegetation or with farm management. Although greater on-farm crop diversity and perennial vegetation conservation in cropland-dominated landscapes were associated with greater richness of Ichneumonidae, neither perennial vegetation nor wasp richness was associated with high parasitism rates of sentinel caterpillars or aphids in the following year. These results suggest that elements of the landscape mosaic are needed to support diverse communities of natural enemies, but pest control services do not necessarily map on to patterns of arthropod diversity. Over the long term, a more diverse community may provide "insurance" against pest outbreaks if a dominant parasitoid is lost, but areas of overlap between biodiversity conservation and agricultural goals must be assessed critically.

The goal of my dissertation was to incorporate habitat quality into metapopulation theory for the conservation of the endangered Ohlone tiger beetle (Cicindela ohlone). Cicindela ohlone is endemic to the few remaining coastal terrace prairies in Santa Cruz County where it forages and lays eggs in bare ground. The prairies were once dominated by bunch grasses, fire, and large grazers that maintained bare ground but now consist of invasive annual grasses with cattle grazing and recreation creating the little remaining bare ground. My dissertation work approached species conservation from multiple scales and each chapter represents those different approaches: habitat quality of metapopulation patches to predict patch conservation value, habitat restoration and adaptive management, population viability analyses, and investigation on how knowledge affects behavior of recreationists in species habitat and the impact of recreation on beetle behavior.

I, along with my collaborators, found that the majority of the remaining Ohlone tiger beetle populations are sustainable and can persist in Santa Cruz County, but only with habitat management. Specifically, creation of bare ground habitat by scraping the ground free of vegetation augments C. ohlone oviposition habitat. Also, requiring cyclists to slow down to speeds of five mph in C. ohlone habitat greatly reduces the negative impact of recreationists on adult behavior. I have shown that these management strategies will increase the growth rates of all C. ohlone populations.

Ensuring that the Ohlone tiger beetle will persist will require not only management of occupied habitats, but also unoccupied sites, particularly to maintain metapopulation dynamics and in the face of the unknown effects of global warming. Habitat management that increases bare ground and forb cover and reduces grass cover, such as controlled grazing, vegetation removal, mowing, or burning are the best options for maintaining C. ohlone persistence. Finally, education and outreach to hikers and bikers in and around Santa Cruz will result in greater understanding and appreciation for C. ohlone conservation and, in turn, result in increased compliance with slowing down in C. ohlone habitats. The Ohlone tiger beetle and its unique coastal prairie habitat can persist into the future, but only with our help.