Summary:
Riverine ecosystems are commonly thought to exhibit relatively continuous downstream gradients in physical conditions and ecological communities. However, recent research suggests that observed longitudinal gradients in riverine ecosystem form and function are quite variable and largely dependent upon local hydrology, geomorphology and climate. The lower Grande Ronde River, which flows through regions with distinctly different geomorphic and climatic conditions, provided a great opportunity to examine the nature of longitudinal gradients in terrestrial and aquatic ecosystem characteristics.