Recognizing and integrating wildlife as Elwha restoration agents

Ecosystem restoration involving large dam removal spans large spatial extents, long time scales, and diverse societal constituencies. Restoration success requires collaboration among partner organizations. Success also can be facilitated by integrating components and processes of the ecosystem itself in restoration planning and practice. We review early and future roles of wildlife in restoration of valleys flooded by Elwha dams, with implications for dam removals on other rivers. Detecting early wildlife responses depended on baseline inventories prior to dam removal, followed by monitoring during and after dam removal. Pre-removal studies revealed patterns of small and mid-sized mammal occupancy, bear movement, amphibian occupancy, and avian distributions and species composition. In the few years since dam removal, wildlife colonization of exposed reservoir beds has been rapid, dominated by early successional and mobile species. Wildlife also perform important restoration functions, and contribute to all nine attributes defining restored ecosystems. This early in Elwha restoration, conspicuous wildlife functions include native seed dispersal to restoration sites, herbivore effects on revegetation, and organic matter dispersal to nutrient-poor sediments. In future decades, diverse wildlife also will help restore terrestrial-aquatic connections by dispersing nutrients from increasing salmon runs to riparian and terrestrial areas. Each of these wildlife roles is influenced by spatial distributions of pre-dam structural legacies and structures placed during active restoration efforts, particularly large woody debris. By placing these structures in locations and configurations that support wildlife functions, restoration planning and practice more effectively integrate wildlife in restoration. Benefits include increasing the rate of restoration progress and directing it along more desirable trajectories. In this way, the collaborative interdisciplinary approach in Elwha restoration can be expanded in future restoration projects to encompass active collaboration with the ecosystem itself

Responses of river-dependent wildlife to dam removal, salmon restoration, and nutrient subsidies in the Elwha River Watershed, Olympic Peninsula, Washington

The ongoing removal of two hydroelectric dams from the Elwha River on Washington’s Olympic Peninsula provides an unprecedented opportunity to study the effects of dam removal and subsequent salmon restoration on river-dependent wildlife species. Salmon are widely known to distribute marine nutrients into freshwater systems, providing benefits to both riverine and upland wildlife communities through improved nutrient availability. We examined two species of river-dependent wildlife (river otter Lontra canadensis, and American dipper Cinclus mexicanus) to gather data on home range and seasonal movement patterns, body condition, and dietary contributions from marine-derived nutrients prior to and during dam removal. We radio-tracked ten river otters in the Elwha River and adjacent Salish Sea, and collected biological samples from all otters captured in the Elwha River as well as 246 dippers captured across four watersheds with varying qualities of salmon runs. We are using stable isotopes (C, N) to track marine derived nutrient contributions to the diets of otters and dippers, species that are both sensitive indicators of aquatic food web quality. In both species, stable-isotope ratios were more enriched in tissues from areas with intact salmon migrations, indicating greater consumption of salmon tissues and potential enrichment of invertebrate prey. In dippers, females breeding in areas with salmon migrations were in better condition and both sexes were more likely to occupy territories in fall. Adult condition patterns were more pronounced behind anthropogenic, compared to natural, obstructions. These patterns indicate that dams have sizeable individual level impacts on aquatic consumers and provide a valuable baseline to track the recovery of this watershed following completion of dam removal