Widespread degradation of streams and riparian ecosystems necessitates a shared stewardship approach that increases ability to prioritize management actions in locations where they have the greatest ecological benefits. Application of geomorphic sensitivity and ecological resilience concepts (recovery potential) can provide the basis for assessing differences in riparian ecosystem response to disturbances and management actions and for prioritizing restoration actions. In the Great Basin of the western U.S., a collaborative research and management team of state, federal, and NGO partners developed a multi-scale approach for assessing sensitivity and resilience that builds on long-term research in the watersheds. The approach asks two key questions: At watershed scales, how does runoff, sediment size and availability, and riparian vegetation types influence disturbance response? At riparian corridor/stream reach scales, how are geomorphic and hydrologic processes and vegetation dynamics related to disturbance response? Information was collected on watershed characteristics (climate, morphometry, geology, vegetation, disturbance) using remote sensing and geospatial analyses, and on historic responses to disturbance using National Agricultural Imagery and Google Earth Imagery. Reach-scale geomorphic, vegetation and disturbance information were collected in the field. Combined geospatial and field data were then used to evaluate relative sensitivity and resilience to disturbance using a scoring process.
Results/Conclusions
In addition to providing a basic understanding of the geomorphic, hydrologic and vegetation characteristics of the watersheds and stream reaches, the assessment categorized watershed sensitivity and resilience into five groups: flood-dominated, armored, fan dominated, deeply incised, and pseudo-stable basin. The categories are based largely on long-term research in the watersheds, and reflect differences in type, magnitude and rate of channel response to disturbance (which primarily involved incision and avulsion processes). The characteristics of each watershed category indicate the potential for future geomorphic and vegetation change and have strong implications for restoration and other management activities in the watersheds. Unlike assessments of riparian ecosystems that characterize ecological integrity (current ecological conditions), the sensitivity and resilience approach provides (1) the ability to understand and predict the responses of streams and riparian ecosystems to disturbances and management actions over time, and (2) the basis for prioritizing riparian ecosystems for management and determining appropriate actions. Involving multiple research and management partners in developing and implementing the approach increases the ability to manage these high value resources across jurisdictions in an integrated and collaborative manner.