Author: Elva Manquera

Birds as Indicators of Klamath River Watershed Health: Informing dam removal planning, adaptive restoration, and evaluating ecosystem function

Klamath Bird Observatory pre-proposal
Sarah M. Rockwell, Jaime L. Stephens, and John D. Alexander

Water rights and dam operations along the Klamath River in northern California have been controversial for decades. In April 2016, the amended Klamath Hydroelectric Settlement Agreement (KHSA) was signed by PacifiCorp and a diverse group of stakeholders proposing to remove four PacifiCorpowned dams (Iron Gate, Copco 1 and 2, and J. C. Boyle) known as the Lower Klamath Project. The Klamath River Renewal Corporation (KRRC) is a third-party, non-profit organization created as part of the amended KHSA to oversee the dam removal process. The removal of the Klamath River dams, currently planned to be completed by the end of 2023, represents the most extensive dam removal and river restoration project in U. S. history. It presents an exciting opportunity to study the ecological effects of large-scale dam removal, which are not currently well-understood. This work is timely – studies should be implemented in 2022 and/or 2023 to collect baseline data so that we can better inform dam removal planning and understand changes that occur post-dam removal.

Klamath Bird Observatory proposes applying the best available science and integrating avian focal species into conservation planning as a component of the Klamath River dam removal and restoration process. Birds are considered excellent indicators of ecosystem health because they respond relatively quickly to habitat change, individual focal species are sensitive to environmental variation at multiple trophic levels and at multiple spatial scales, and as a community, birds are relatively easy and cost-effective to monitor (RHJV 2004). Our data-rich tools provide quantitative measures of watershed health that can be used to evaluate management alternatives, set measurable management targets, inform on-the-ground restoration design, and provide a cost-effective means to monitor restoration outcomes and evaluate effectiveness of management actions. We will apply results from decades of monitoring in the Klamath Watershed, including management-relevant studies of Gold Ray Dam removal (Stephens 2017) and the Trinity River Restoration Program (Stephens et al. 2016, Rockwell and Stephens 2018, Stephens and Rockwell 2019), along with established bird and habitat conservation plans(e.g., RHJV 2004) and site-level monitoring, to inform adaptive management of restoration.

We propose the following applications of birds as indicator species to inform management, set restoration targets, and measure success:

1. Well established bird-habitat associations and site-level monitoring can help guide the adaptive management process regarding dam removal and the subsequent restoration of riparian vegetation alongside the river channel that will reform as reservoir levels drop. We will inform dam removal planning and restoration design with existing science, evaluate restoration success by studying the density and reproduction of a suite of focal species that require different aspects of riparian vegetation for habitat use, and perform vegetation surveys to associate specific features of vegetation structure and composition with benefits to bird populations and thus other wildlife. Riparian vegetation on a successful trajectory will support an increasingly abundant and diverse bird community as it matures. Results can be used to determine which revegetation techniques lead to a trajectory towards successful ecological function and which could be improved through cycles of adaptive management. Active revegetation efforts are currently planned, but in their absence, we can monitor response to natural regeneration and ecological function for wildlife via passive revegetation over time.
2. Birds can also serve as indicators of improved in-stream ecological function. Removal of the four dams would allow salmon to return to 300 miles of spawning and rearing habitat for the first time in decades. Salmon are important carriers of marine nutrients to terrestrial systems. Previous studies have shown that songbirds achieve greater densities (Christie and Reimchen 2008), and that aquatic birds have improved body condition, more successful reproduction, and higher annual survival in salmon-bearing vs. non-salmon-bearing streams and in areas below dams that salmon can access (Tonra et al. 2015, 2016). These benefits to bird populations are associated with increased levels of marine-derived nutrients in their body tissues. Birds can thus serve as indicators of this restored trophic cascade that brings valuable marine-derived nutrients upstream and to terrestrial systems. We propose to monitor bird abundance as well as body condition, reproductive success, and return rates of several focal species both above and below the dams, and before and after removal (i.e., before-after-control-impact study design). This will demonstrate the success of dam removal or identify the need for additional restoration action to fully achieve restored riparian areas and ecological processes.

Despite the number of dam removals planned in the U.S., dam removal science is in its infancy (Bellmore et al. 2016). Here in the Klamath-Siskiyou Bioregion, we are well-positioned with established science to inform dam removal planning, develop a monitoring strategy to inform adaptive restoration and measure the success of ecological function of both in-stream and riparian ecosystems. The Klamath dam removals, one of the largest river restoration projects in history, provide a unique and timely opportunity to study ecological response to large-scale dam removal, an aspect that is commonly overlooked. Knowledge of these effects will help inform future dam removal processes and restoration efforts.

References

Bellmore, J. R., J. J. Duda, L. S. Craig, S. L. Greene, C. E. Torgersen, M. J. Collins, and K. Vittum. 2016. Status and trends of dam removal research in the United States: Status and trends of dam removal research in the U.S. Wiley Interdisciplinary Reviews: Water.
Christie, K. S., and T. E. Reimchen. 2008. Presence of salmon increases passerine density on Pacific Northwest streams. The Auk 125:51–59.
Riparian Habitat Joint Venture (RHJV). 2004. The riparian bird conservation plan: A strategy for reversing the decline of riparian associated birds in California. Version 2.0. California Partners in Flight and Point Reyes Bird Observatory, Petaluma, CA.
Rockwell, S. M., and J. L. Stephens. 2018. Habitat selection of riparian birds at restoration sites along the Trinity River, California. Restoration Ecology 26:767–777.
Stephens, J. L. 2017. Short-term response of vegetation and the riparian bird community to dam removal on the Rogue River, Oregon. Ecological Restoration 35:328–340.
Stephens, J. L., and S. M. Rockwell. 2019. Short-term riparian restoration success measured by territory density and reproductive success of three songbirds along the Trinity River, California. The Condor 121:1–12.
Stephens, J. L., S. M. Rockwell, and E. E. Armstrong. 2016. Trinity River bird and vegetation monitoring: 2015 report card, version 1.0. Klamath Bird Observatory, Ashland, OR.
Tonra, C. M., K. Sager-Fradkin, and P. P. Marra. 2016. Barriers to salmon migration impact body condition, offspring size, and life history variation in an avian consumer. Ecography 39:1056–1065.
Tonra, C. M., K. Sager-Fradkin, S. A. Morley, J. J. Duda, and P. P. Marra. 2015. The rapid return of marine-derived nutrients to a freshwater food web following dam removal. Biological Conservation 192:130–134.