Abstract: Riparian forests have been well documented for their ecosystem functions and services including improving water quality by reducing soil erosion and nutrient runoff, creating biodiversity hotspots, and serving as a natural solution to climate change through carbon sequestration. Riparian forests tend to be more productive compared to their upland counterparts and models have predicted that these habitats can potentially sequester significant amounts of carbon within their soils. Soil microbes play an important role in the soil carbon cycle, but are rarely investigated in studies on carbon sequestration. Additionally, land use change can have profound impacts on soil physicochemical properties but the associated changes in soil microbial communities are poorly understood. In this study, we investigated the efficacy of riparian buffer restoration in improving soil microbial community composition and function as well as long-term soil carbon sequestration. A chronosequence (0-30 years) of restored riparian buffers in the Shenandoah Valley of Virginia (n=10) was paired with an upstream, unrestored pasture (n=10) to account for differences in soil type and land-use history among restoration sites. Soil samples were collected at each farm within a three-week period in the early summer. Soil microbial community composition was assessed using phospholipid fatty acid analysis (PLFA) while their function was assessed through soil respiration rates. Soil physical and chemical properties (moisture, pH, aggregate stability, bulk density, total nitrogen, and total carbon) was also quantified. Time since restoration and soil quality indices predicted the soil microbial community composition. Restored riparian buffers showed a greater diversity of microbial composition and function and higher soil carbon concentrations than the control sites where cattle had access to the streams. Through connecting with local farmers and investigating how current restoration strategies are impacting soil health, we demonstrate that restoring riparian habitat within active cattle pastures can be mutually beneficial for ecosystem health and rural livelihoods.
