Dykstra, A. 2024. Restoring insects and their ecosystem services through landscape-scale conservation. Dissertation, Michigan State University, East Lansing, MI.

This dissertation examines the effects of two landscape-scale conservation strategies on insects and insect-based ecosystem services. Biodiversity and the benefits we receive from it are declining rapidly. A major driver of biodiversity loss is land use, particularly agricultural land use. Habitat loss and fragmentation are often a result of human land use. In this dissertation, I
explore two conservation strategies that aim to combat the effects of agricultural intensification and habitat fragmentation. In chapter one, I tested the effects of landscape corridors on two flying insect communities: nocturnal moths and wild bees. Landscape corridors connect fragmented habitat patches with the goal of restoring landscape connectivity. I measured the
abundance, diversity, and community composition of moths and wild bees in a landscape scale habitat fragmentation experiment that manipulates both habitat connectivity and the edge-to-area ratio of habitat patches. I found that landscape corridors have neutral effects on moth abundance and richness and bee richness, but have a negative impact on bee richness. Although previous studies have found landscape corridors to be beneficial for many taxa, my results point to the complicated task of designing conservation strategies that benefit all taxa. In chapter two, I examined the effects of prairie strips in row crop systems on caterpillar-parasitoid interactions
and pest control services. Prairie strips are a method of agricultural diversification which aim to support biodiversity and ecosystem services in agricultural landscapes by increasing the plant diversity present in the system. I found that fields that contain prairie strips can both support
diverse communities of parasitoids and caterpillars while supporting pest control services. In chapter three, I tested the effects of prairie strips, and their landscape context, on pollinators and pollination services to crops. I found that fields with prairie strips host a greater diversity and abundance of pollinators compared to fields without prairie strips. Additionally, I found that
prairie strips are beneficial for pollinator communities regardless of their position within a field or the crop in which they are situated. I did not find evidence that prairie strips bolster the pollination ecosystem services provided to neighboring crops. Together, chapters two and three
point to the efficacy of prairie strips to conserve biodiversity, including interactions between species and some of the ecosystem services provided by biodiversity.

Associated Treatment Areas:

• T2 No-till Management
• T7 Early Successional
• T3 Reduced Input Management
• T4 Biologically Based Management
• ACSE Plots LTAR Aspirational Cropping Systems Experiment Plots
• MCSE Main Cropping Systems Experiment

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