Agricultural landscapes in the last century have expanded to meet the global demands of food, fuel, and fiber necessary to support growing populations. Although the innovation of equipment, technology, and intensified agricultural practices have contributed to world food production, it has come at the cost of habitat loss through pollution or fragmentation, and a decline in global biodiversity, in particular, the decline of insect populations. Highly simplified agricultural landscapes have low habitat diversity, habitat amount, and simplified configuration that limits the dispersal of insects and their provision of ecosystem services that sustain crop yield via pollination, pest suppression, and nutrient-rich soils. As agriculture is a primary global land use, the threat of insect loss amid the uncertainty of changing climates will have lasting effects on global food security for generations to come. As such, it is necessary to shift from intensive systems dependent on high-input of pesticides, tillage, or monocultures, to agricultural landscapes that are multifunctional and support both human and ecosystem health and resiliency.Perennial prairie strips or prairie plantings are a conservation tool to enhance ecosystem service provision in simplified landscapes and provide alternative habitat and food resources for wildlife. Insects contribute to agriculture through necessary ecosystem services and may benefit from the establishment of non-crop prairie plantings in agroecosystems. This dissertation focused on ground beetles, or carabids (Coleoptera: Carabidae) as beneficial predators of insect pests and weed seeds. Carabids are useful indicators for ground-dwelling arthropod diversity as they are sensitive to changes in agricultural management both above- and belowground, and benefit from the addition of native non-crop habitat within agricultural landscapes. In 2019, prairie strips were planted in two conservation-oriented treatments at the Kellogg Biological Station (KBS) Long-term Ecological Research (LTER) Main Cropping Systems Experiment (MSCE) in southwest Michigan. The two treatments include Reduced Input, using one-third the conventional application of pesticides, and Biologically Based, using no synthetic inputs. In this dissertation, I investigated a) the effects of long-term management and cropping treatment, before the addition of prairie strips, on carabid diversity and activity-density; b) how establishment of perennial prairie strips influenced carabid community composition in both the strip and adjacent row crop; and c) the spillover of predation services from the prairie strip into the row crop. In Chapter One, I broadly reviewed the literature on agricultural landscape simplification and agricultural intensification, including the current global biodiversity crisis. I further described historic and current conservation interventions to reduce biodiversity loss and augment ecosystem services within agriculture. The majority of the literature review focused on carabids as beneficial providers of pest and weed seed management, and the impact of various agricultural practices on the diversity and abundance of carabids within agroecosystems. In Chapter Two, I addressed questions raised in the literature review of the long-term impacts of agricultural management on carabids by comparing the 2019 carabid community at the KBS-LTER to a similar study conducted in 1994-95. I found a severe decline in carabid abundance and a turnover in carabid species from the previously dominant community. Although we did not determine a singular reason for the decline, innovation in pest and weed management over the last three decades, including the widespread application of pesticides, likely reduced prey abundance and compounded the effects of landscape simplification on resource availability. In Chapter Three I investigated the effects of prairie strip establishment on carabid community composition, including the spillover effects from the prairie strip into the adjacent row crop. Carabid activity-density doubled one year after seeding the prairie strip, and the response to prairie strips varied by cropping treatment. I also found that after four years, prairie strips contributed to increased biodiversity both within the strip and within the center of the row crop. Given the evidence for spillover of carabid community biodiversity from prairie strips, I further studied the potential for pest suppression services in Chapter Four. Using sentinel insect pests commonly found in Midwest, US agriculture and exclosures to limit predation to arthropods, I found relatively high pest suppression across treatments and a preference for prairie strips during early- and late-season when resources are scarce in agricultural landscapes. I conclude my findings in Chapter Five and discuss the broader implications of my dissertation research on conservation interventions for the prevention of biodiversity loss and ecosystem service provision, including key limitations or challenges of current sampling methods or experimental designs, and opportunities for future research in this field. Agriculture is not a closed system and neither is scientific research; in Appendix One I describe my community-engaged research project on prairie strip adoption. By conducting focus groups and partnering with Conservation Districts, I review farmer perspectives on challenges to the future of agriculture, and best practices for prairie strip establishment and maintenance in Michigan. By supporting ecosystem health in agricultural landscapes, we can also support the health and productivity of farming communities.
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