RELATIONSHIPS AMONG GEOMORPHOLOGY, HYDROLOGY AND VEGETATION IN RIPARIAN MEADOWS: RESTORATION IMPLICATIONS

Vegetation patterns and dynamics within riparian corridors are controlled largely by geomorphic position, substrate characteristics and hydrologic regimes. Understanding management and restoration options for riparian meadow complexes exhibiting stream incision requires knowledge of the relationships among riparian vegetation, geomorphic controls, and hydrologic regimes. The dominant plant species and vegetation states associated with meadow complexes in the central Great Basin are determined by water table depths and substrate characteristics and serve as indicators of hydrologic processes. Abiotic thresholds exist between vegetation states that can be defined by water table depths and substrates, while biotic thresholds exist within vegetation states that can be evaluated based on species composition. Stream incision associated with meadow complexes often results in declining water tables, abiotic threshold crossings and loss of wet meadow ecosystems. In actively incising systems, restoring wet meadow ecosystems once water tables have dropped is unrealistic. Restoration and management activities must be based upon the current potential of these systems to support a given vegetation state. This may involve prevention, i.e., stabilization of incising streams, or active restoration, i.e., management or revegetation based on the current water tables and substrate types.