Evaluating Riparian Restoration Success: Long-Term Responses of the Breeding Bird Community in California’s Lower Putah Creek Watershed

Restoration of river processes and riparian vegetation is a high priority, particularly in the western United States, where it provides critical habitat for fish and wildlife along with many other environmental and economic benefits, yet few studies have quantified long-term responses of wildlife. We evaluated responses of the breeding bird community to restoration and management of the lower Putah Creek watershed in the Central Valley of California following the establishment of the Putah Creek Accord in 2000, an historic agreement designed to improve ecosystem structure and function and protect the livelihoods of farmers and residents along the lower creek. We surveyed the breeding bird community at 14 sites distributed over 38 km of the creek between 1999 and 2012, and we detected significant increases in the abundance of 27 breeding bird species as well as increases in the size and diversity of the entire breeding bird community, which could not be accounted for by broader regional trends or the influence of local nest box installation. Further, changes in the watershed favored riparian and woodland-associated species over synanthropic species. However, in comparison with Central Valley Joint Venture density objectives for seven riparian focal bird species, there is still considerable room for improvement, particularly at sites farthest downstream. Overall, our results echo shifts in the Putah Creek fish community and provide evidence that the Putah Creek Accord and subsequent management actions have contributed to a long-term improvement in riparian ecosystem condition for both aquatic and terrestrial organisms.