Browsing by Author "Mouser, Joshua Braden"

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    Using an interdisciplinary approach to improve efficacy of agricultural conservation practices for protecting stream health
    Mouser, Joshua Braden (Virginia Tech, 2024-08-19)
    Protecting water quality, biota, and ecosystem services of streams (cumulatively referred to as stream health) while increasing food production is a major global challenge. One way to balance these often-competing interests is through the installation of agricultural conservation practices, such as excluding livestock from streams via fencing and adjusting grazing patterns. However, conservation practices often do not improve stream health as expected. Failure to achieve stream health outcomes may be due to biophysical (e.g., conservation practices are not appropriate for the landscape) or social reasons (e.g., agricultural producers are not willing to use conservation practices). Therefore, the goal of my dissertation research was to understand factors influencing effectiveness of conservation practices using an interdisciplinary approach that integrates ecological engineering, ecology, and social science. My research focuses on southwest Virginia, a karst region where cattle grazing is common. In the introduction, I developed a social-ecological framework that outlines how the natural and social sciences can be used to guide effective placement and implementation of conservation practices and explain why interdisciplinary approaches are often necessary due to social-ecological connections that influence efficacy (i.e., feedbacks, heterogeneity, time lags, and thresholds). In Chapter 1, I modeled pollutant transport to characterize watershed features that contribute disproportionate amounts of pollutants to streams. I found that water, and associated nitrate, is primarily entering streams through subsurface pathways, whereas sediment is entering the stream through streambank erosion. Therefore, a combination of conservation practices that stop nitrogen at its source (e.g., nutrient management plans) and stabilize streambanks (e.g., fenced riparian buffers) could be useful for protecting stream health. For Chapter 2, I sampled water quality, habitat, and macroinvertebrates from 31 streams within sub-watersheds that span a range of pollutant yields, conservation practice densities, and agricultural land use extent to understand the pathways through which conservation practices influence stream health. Agricultural land use increased total nitrogen and decreased macroinvertebrate diversity, but conservation practices stabilized nitrogen and improved bank stability. Despite such improvements, adverse effects on water quality and habitat still limited the biotic assemblage. Therefore, innovative conservation practices, higher densities of existing practices, or allowing more time for the effects of existing practices to improve water quality and habitat may be required to achieve stream health goals. For Chapter 3, I surveyed producers to understand if they continue to use their conservation practices after their cost-share contracts end (i.e., persistence) and factors that influence persistence. Persistence was most strongly related to producers' attitudes towards the conservation practice, producers' motivations, and practice durability. Therefore, persistence could be encouraged by using producers' motivations to focus messaging on ways conservation practices are achieving producers' goals and allocating more funding to practice maintenance. Overall, my interdisciplinary approach led to a greater understanding of pollutant dynamics, the pathways through which conservation practices influence stream health, and social constraints to persistence. This knowledge can inform what conservation practices may be most effective and strategies to keep appropriate practices on the landscape long enough to achieve stream health goals.