Patch habitat contributions to biodiversity, ecosystem services, and crop production in the Northern Great Plains

Abstract

In response to global calls for sustainable food production and biodiversity conservation, we explored the potential of conserving small non-crop patch habitats, or ecological refugia, to meet food production and conservation objectives within agroecosystems. This dissertation considered multi-objective outcomes of conserving ecological refugia within dryland grain production systems in the Northern Great Plains (NGP) that included agronomic, ecological, and economic tradeoffs, and policy implications. First, we proposed the union of production oriented and ecologically oriented agriculture within a precision agroecology framework. We advocated for the merger of precision agriculture technology and agroecological principles to transform food systems. First, we explored the potential to incorporate biodiversity into crop fields using precision conservation to conserve low-yield areas as patch habitat and manage for sub-field variation. Second, we found that small ecological refugia increased plant and arthropod diversity, provided ecosystem service tradeoffs, and enhanced crop yield, but not crop quality in three dryland grain production systems in the NGP. Third, we found that local biodiversity response to landscape context was scale-dependent, and that correlations between landscape variables and local biodiversity were lowest at the most distant extent (< or = 5km from the ecological refuge). Partial R-squared values were highest when both local and landscape variables were included, and when composition and configuration variables were included in models predicting local biodiversity. These results suggested that local conservation efforts should be coordinated with landscape-level efforts to enhance biodiversity and ecosystem service provision across agricultural landscapes. Last, we found that removing low-yielding portions of crop fields from production could provide positive returns on investment to farmers but profitability depended on the size of the patch removed, harvest year, grain price received, potential yield gain associated with ecosystem services, and government conservation program incentives. Additional noneconomic policy levers may be needed to incentivize adoption of on-farm conservation practices. Looking forward, ecological refugia have the potential to host biodiversity, increase agroecosystem functioning, and benefit crop production. Future research should investigate site-specific practices for patch habitat conservation, determine effective incentives for on-farm conservation, and coordinate landscape-scale efforts to create and connect agroecological landscapes.