Western riparian ecosystems are subject to a host of unique restoration challenges, which lend themselves to exciting ecological research questions. Innumerable western riparian areas are affected by river damming, species invasions, flow alteration, livestock grazing, channelization, pollution and land use conversion of historical flood zones, leading to species extinctions, shifts in biotic communities, and changes in ecosystem function. Some solutions are available, however the complexity of these ecosystems makes restoration often difficult. In this oral session, we will hear from leaders in western watershed restoration research, including representatives from several states, universities and federal agencies.

The foci of riparian restoration research ranges from abiotic processes,such as stream flows and sedimentation, to biotic communities, including integration of faunal and floral elements and individual endangered species. A great deal of attention is paid to the role of dominant plant invaders of riparian ecosystems, such as Arundo and Tamarix. These plants can cause alterations in geomorphology and other abiotic factors while also acting as indicators of anthropogenic changes, such as altered flow regimes. Thus, simply removing a species is unlikely to restore the historical community. Furthermore, the ecological relationships of one species may differ across geographic ranges, complicating restoration implications. This session will include several region-comparison papers, and will bring together scientists from different areas across the west to discuss restoration of riparian watersheds altered by anthropogenic impacts.

The session will begin with a quantitative synthesis of riparian restoration sites across the west, revealing the relative importance of various environmental predictors of the success vs. failure of re-vegetation projects. The next papers explore challenges to restoration, including difficulties in re-instating natural stream flow regimes. The focus then shifts to restoration solutions, beginning with a discussion of restoration potential from both seedbank and active revegetation, and the use of soil amendments to mitigate stress. We will also consider restoration from a focal species habitat perspective. We will end with a quantitative synthesis of the more common restoration approaches, and finally a qualitative synthesis of western riparian restoration and the current state of the field.