Impact of Grazing Management on Soil Carbon Storage and Spatial Area of Wetlands Along the National Historic Trails Corridor, Wyoming.

Wetlands are an important resource for C sequestration, water storage, sediment capture, and biodiversity. Alterations in wetland area and functionality are often linked to land management decisions, such as grazing practices. Potential changes are quantified by measuring differences between historically grazed wet meadows and adjacent grazing exclosures, and identifying the pathway of those changes. A paired-comparison of grazing exclosures and adjacent comparison areas examined differences in soil characteristics across hillslope gradients due to grazing pressure. Hummocks and interspaces were also compared to evaluate whether soil C varies within the micro-landscape. Current hydric soil boundaries are delineated using Indicators of Reduction in Soil tubes and compared with soil morphological descriptions. Results from preliminary sampling conducted at the center of each actively grazed wetland suggest significant differences in hummock and interspace soil organic C (SOC) content while there is less than significant differences in SOC content within grazing exclosures. These results indicate wetland recovery following a decrease in grazing pressure. Overall average SOC content of samples in actively grazed areas and exclosures were not significantly different. Field observations suggest greater contrasts in SOC content along wetland boundaries and show evidence of disturbed and shrinking wetland resources. Findings may support the implementation of grazing management strategies which promote an increase in C sequestration, wetland health, and resilience to climatic changes.