Hydrogeomorphic characterization of rivers and implications for ecological processes and ecosystem services

Riverine landscapes are organized longitudinally into hydrogeomorphic patches at different spatial scales. At the valley-to-reach level, these hydrogeomorphic patches are known as functional process zones (FPZs). Some of the many examples of FPZs are meandering, braided, and anabranching channels. FPZs are repeatable and only partially predictable in position (less so among ecoregions). Riverine landscapes can be characterized (“river typing”) at various levels, including FPZs, using remotely sensed data and rigorous statistical analyses that allow the FPZs to emerge with minimal errors from human bias. Some of the approaches to typing rivers are described in the Riverine Ecosystem Synthesis (Thorp et al. 2008, Academic Press) and briefly discussed in this seminar. Because they differ substantially in hydrogeomorphic characteristics, FPZs are also likely to vary significantly in community structure, ecosystem function, and ecosystem services, and thus will respond differently to efforts at river rehabilitation. In our seminar, we discuss hypotheses on how these fundamental and applied ecosystem processes vary among FPZs and cite actual examples of the relationships of FPZs to the distribution of aquatic species.