Factors affecting spatial and temporal dynamics of an ungulate assemblage in the Black Hills, South Dakota

Wildlife stocking-rate decisions are critical to the long-range stability of range ecosystems and depend on accurate estimates of forage production. Decision-support tools, such as forage production models, can be especially important to land management in the Northern Great Plains, where climate is variable and drives forage production. Natural Resource Conservation Service (NRCS) production tables are important tools for range managers because they estimate forage production by soil units and do not require substantial time or money. Custer State Park (CSP) estimates annual forage production, which dictates wildlife stocking rates, using a model that incorporates NRCS estimates. CSP modifies these estimates with a moving-two-year mean of annual precipitation. However, this modified NRCS model relies on several un-tested assumptions. It is necessary to determine the efficacy of this model and assess whether other model formulations are appropriate. Our objectives were to measure forage production in CSP and develop a spatially explicit model to predict species-specific biomass, as well as woody twig and foliage biomass, and compare estimates from this model to the modified NRCS-based model used by CSP as well as unmodified NRCS estimates. We used clipping and weighing and visual obstruction techniques to measure forage biomass in