Get reliable rangeland science

Management of rangeland ecosystems is challenged by high heterogeneity in soil-geomorphic attributes, low and variable precipitation, and ecosystem dynamics prone to threshold or hysteresis type transitions. Available resources for managing rangeland landscapes are typically low, particularly when compared to the land area occupied. The NRCS Ecological Site Information System and associated Ecological Site Descriptions (ESDs) and State and Transition Models (STMs) provide information and tools to help address these management challenges. ESDs classify landscapes based on soils, topography, and climate. STMs are imbedded within ESDs and provide descriptions of site dynamics, including putative ecological states, transitions between states and restoration pathways. Development of ESDs is primarily focused on patterns in soil-vegetation relationships. Although some soil health parameters are described for the reference state (e.g. rangeland health reference sheets), they are not often fully integrated into ESDs. In many rangeland ecosystems, ESDs can provide context for interpreting soil health data, whilst changes in soil health indicators over time can inform rangeland managers of at-risk of transitioning to an undesired state. As an example of how soil health indicators can add value to rangeland ESDs, we provide results from a recent interagency STM workshop where we successfully incorporated biological soil crusts into a STM from the Colorado Plateau region of the southwestern U.S. In this example, loss of biological soil crusts help define an at-risk phase indicating risk of transition to an undesired state. In rangeland systems of the U.S., land-use change and intensification is occurring at astounding rates. Successful restoration of rangeland ecosystems following soil disturbance will likely need to address soil loss and degradation. Integrating soil health concepts and ESDs will improve our understanding of how soil quality varies over space and time in rangeland ecosystems and help facilitate adaptive management of rangeland landscapes in the US and globally.