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Conversion of natural grasslands for agricultural uses and intensification of agricultural production has been a major cause of natural ecosystem fragmentation and biodiversity loss. Diversifying agricultural landscapes by adding semi-natural grasslands can potentially help couple agricultural production (i.e., providing food, fiber, and energy to a growing human population) with environmental stewardship, enhancing ecosystem health, and increasing biodiversity. To ensure long-term ecological benefits of buffers and to maintain them as suitable habitat for prairie-associated species, periodic disturbance is required to keep buffers in an early-successional grassland plant community. In this dissertation, I fill knowledge gaps about biodiversity of semi-natural grassland buffers within agroecosystems. I investigate influence of prairie-history on buffer forb communities and effects of disking and burning on semi-natural grassland buffer plant and butterfly communities. I also investigate suitability of using butterflies as surrogates of birds and plants on semi-natural grassland buffers. Prairie-history influenced buffer forb communities, and disking increased forb richness and abundance. Disturbance guild butterflies responded positively to disking, most likely due to increased availability of nectar-rich plants. Grassland guild butterflies were not impacted negatively by disking or burning. Responses of plants and butterflies to disking and burning varied between sampling years. Effects of disking in fall 2007 persisted for two growing seasons, but I observed little effects of disking in fall 2008. Butterflies, with the possible exception of Pearl Crescent, were unsuitable as surrogates for birds. In contrast, butterflies, including Pearl Crescent, showed suitable or marginally suitable correlations with plants. Results of my study should help agricultural producers accomplish environmental conservation objectives and provide science-based information for developing and refining USDA practice standards and policy.

Imported fire ants are invasive and cause injury to people, crops, livestock and wildlife. Disturbance may increase abundance and activity of fire ants. However, native grass field buffers established for grassland birds require periodic disturbance. I experimentally tested if fire ant mound density and foraging activity changed after burning and disking in native grass buffers and examined relationships among fire ants, vegetation, and grassland bird and butterfly metrics in undisturbed buffers. In 2008, disking increased mound density and foraging activity, but burning did not. In 2009, disking had no effect, but effects of disking the previous season persisted. Fire ant metrics were not related generally to bird or butterfly metrics. Mound density and foraging activity were related negatively to grass cover and related positively to forbs. Burning had less influence on abundance and activity of fire ants, and may better conserve grassland habitats in areas with fire ants.

Riparian wetlands may provide numerous ecosystem services, including water quality protection, food and fiber supply, wildlife habitat, and carbon sequestration. In recent years, riparian forests have received increased attention and funding for riparian forest restoration projects. Unfortunately, failures of riparian restoration efforts are likely due to mortality of planted trees. Tree mortality is commonly attributable to several factors, including selection of species that are not well suited to the wetland sites, inadequate planting densities, soil compaction associated with former agricultural activities, lack of microtopographic relief that allow small seedling to survive on wet sites, competition by herbaceous plants, and browse. Selection of well-suited species, dense planting and use of mechanical soil site preparations are all potential remedies to partially address success of wetland restoration plantings. Riparian restoration projects have historically been undertaken with goals of improving water quality and/or wildlife habitat, but in recent years there has been increased valuation of carbon sequestration. Carbon valuation appears to be increasing, but more research is needed to determine rates and pools of carbon accumulation in riparian areas. Our research quantifies forest establishment effects on multiple carbon pools in a densely planted, 12-year-old old-field riparian restoration. Our research evaluated the effects of four soil mechanical site preparations (bed, disk, pit, and mound and rip) and species selection (American sycamore (Platanus occidentalis) and willow oak, (Quercus phellos) on forest establishment and carbon storage across multiple pools, namely in planted trees, herbaceous vegetation, fine roots, organic soil horizons, and the mineral soil. At 12 years, we found that species selection was more important to carbon storage than site preparation. American sycamore was well suited to the site and had better survival than willow oak (64% vs 42% survival). American sycamore also stored more carbon across all site preparations than willow oak. Measured carbon storage averaged 74.8 Mg ha-1 for American sycamore treatments and 63.1 Mg ha-1 for willow oak treatments. The plots were densely planted (1.2 m (4ft) by 1.8 m (6ft) spacing), and forests were established even in higher mortality willow oak plots. These results indicate that high planting density is potentially a viable practice for establishing riparian forest cover, especially if desired species are marginally site suited or other survival inhibiting factors exist. / Master of Science / Riparian forests located within the floodplain of streams are known to protect stream water quality, provide wildlife habitat, and store carbon. Due to these benefits, trees may be replanted on riparian areas that were formerly used for agriculture. Unfortunately, trees planted on these restoration sites have often died. The tree mortality may be due to planting incorrect tree species that may struggle on wet floodplains, soil compaction from agricultural practices, not enough trees being planted, and restored floodplains lacking small, elevated areas common across natural wetlands known to favor tree rooting and survival. Reasonably, selecting species that are well suited to a specific site, planting trees more densely, and using plowing methods designed to break up compaction and create some relief in elevation would amend these issues. Traditionally, floodplain restorations have focused on improving water quality and providing habitat for wildlife, but the benefits of storing carbon have become increasingly valuable in recent years. While we know that wetlands store carbon, research is needed to examine how quickly and where carbon is stored. Our research quantifies forest establishment and carbon storage of very densely planted, 12-year-old American sycamore (Platanus occidentalis) and willow oak (Quercus phellos) plantations. This research examines the effects four soil tillage methods and tree species selection had on tree survival and carbon storage. Carbon storage was measured in vegetation, soil, and small roots. Twelve years after planting, species selection had a greater impact on carbon storage than soil tillage methods. No tillage method altered survival or total carbon after 12 years, but American sycamore was found to have better survival and more carbon than willow oak in all soil tillage treatments. Both species were successful in establishing planted forests on the floodplain, but the success was aided by the very high initial numbers of planted trees that ensured enough trees would survive on the site even after trees were lost to mortality. Creation of willow oak forests benefitted more from dense planting, as it was less suited to the site and more planted willow oaks died. We recommend tillage for compacted soil, selecting the most suitable tree species, and planting adequate numbers of trees.