Effects of beavers on soil carbon and nitrogen storage and stream carbon spiraling in the Pole Mountain Unit of Medicine Bow National Forest

With the recovery of beavers (Castor canadensis ), a species that modifies ecosystems, there is need for improved understanding of their effects on landscapes, including carbon and nitrogen cycling and ecosystem services. This study explores the effects of beavers on carbon and nitrogen in the Pole Mountain Unit of Medicine Bow National Forest. The first objective was to quantify and characterize carbon and nitrogen content in beaver pond sediments and associated wetland soils and to estimate landscape (SOC) storage due to beavers. In addition, the impacts of the stage of beaver pond development on SOC storage were analyzed. The second objective was to estimate the effect of beavers on carbon spiraling metrics by measuring stream and beaver pond metabolism, organic carbon concentrations, and hydrologic characteristics. The Pole Mountain Unit of Medicine Bow National Forest contains an estimated 3.2 x 106 Mg SOC, and wetlands associated with beaver activity account for an estimated 3.8 x 105 Mg SOC, indicating that they are important regional sinks for carbon. Carbon and nitrogen concentrations in the soils and sediments were highly variable and most likely influenced by landscape characteristics in addition to stage of beaver pond development. The organic carbon spiraling length was 18.7 km in the stream and 0.1 km in the beaver pond. Both the stream and the beaver pond were heterotrophic during the measurement period. The results of this study will assist in better understanding the role of beavers in global carbon and nitrogen cycling and their contribution to ecosystem services. This information will also assist in making informed land management decisions regarding beavers in mountainous headwaters.