Energetics of canvasbacks staging on an Upper Mississippi River pool during fall migration

In the past 30 years, canvasback ducks (Aythya valisineria) have switched from traditional midwest staging areas on inland lakes and the Illinois River to backwater pools of the Upper Mississippi River (UMR). An energetic approach that integrated field observations of free-living canvasbacks with controlled laboratory experiments on captive ducks was used to study fall staging on Lake Onalaska (Navigation Pool 7, UMR) near LaCrosse, Wisconsin. Time-activity budgets of canvasbacks differed by sex, year, date, time, and weather. Males spent more time foraging than females (20.8% to 17.9%), and canvasbacks foraged more in 1983 than in 1984 (24.4% to 15.8%), during the peak week of staging (22.4%), and at night (28.0%). The staging population of canvasbacks on Lake Onalaska averaged 83% male, but females may have stayed for a shorter time than males. Energetic costs of resting, captive ducks were found to increase (16.9 to 43.8 KJ/h) as water temperature decreased (35 to 0(DEGREES)C). Mean resting costs on water were 2.0 times a basal metabolic rate (BMR), and diving costs were 7.7 times BMR. In controlled studies of functional response, canvasbacks foraging on American wildcelery (Vallisneria americana) winter buds consumed 360/h at densities above 30/m(\u272). Males were more efficient foragers than females. Winter buds near the substrate surface were taken more easily than winter buds located deeper. Canvasbacks metabolized 79.2% or 2.32 KJ of a winter bud. An estimated 0.18 winter buds/dive or 2.7 clams/dive are needed to exactly balance diving costs. Staging canvasbacks assimilated 2600 KJ/day, and assuming that 50% of this energy is converted to fat, they gained 32.4 g of fat/day

Waterbird monitoring and habitat association modeling to inform tidal marsh restoration in an urbanized estuary

The San Francisco Bay (SFB), like many other urbanized estuaries, is a critical wintering and stop-over area for migratory waterbirds. More than a million wintering waterbirds annually rely on a mosaic of natural and managed habitats in SFB, including former salt ponds. The South Bay Salt Pond Restoration Project plans restore 50 to 90% of a 6,100 hectare former salt production pond complex to tidal marsh, while maintaining the rest as foraging and roosting areas for migratory birds. Since 2002, we have evaluated migratory waterbird use of pre- and post-restoration salt ponds in south SFB. Our approach has been to use monthly surveys, applied studies and modeling to evaluate avian response to this changing habitat. Trend analyses indicate that overall waterbird numbers have nearly doubled across the complex from 2003-2014. Dabbling ducks increased significantly during initial phases of the project, while diving ducks, small and medium shorebird abundances declined initially, but rebounded in recent years. We modeled relationships between abundances of multiple species and habitat characteristics at both landscape and micro-scales. Modeling results suggest that the importance of different habitat characteristics varies among waterbird guilds. For example, foraging diving duck abundances were higher in deep, un-breached ponds, located close to the edge of SFB, while foraging small shorebirds predominated in shallow, breached ponds containing islands. Our research highlights important habitat characteristics both within and across wetland areas, and provides a unique opportunity to guide future management and restoration decisions for multiple species across large landscapes in SFB and other urbanized estuaries

Restoration of the Nisqually River Delta and increased rearing opportunities for salmonids

Estuarine wetlands in the Salish Sea provide important rearing habitat for migrating juvenile Pacific salmon, contributing to their overall productivity and ocean survival. Substantial loss of historical estuarine habitat in the Salish Sea due to diking, draining and development has contributed to the decline of Pacific salmon populations (Oncorhynchus spp.). The return of tidal inundation through a series of dike removals to 364 hectares of the Nisqually River Delta (Olympia, Washington, USA) represents one of the most significant advances to date towards the recovery of the threatened Nisqually Fall Chinook stock. Our objective was to assess the collective Nisqually Delta restorations in terms of increased rearing opportunity for juvenile salmon. Metrics consisted of physical conditions that allow juvenile salmon to access the estuarine restorations such as delta connectivity, full tidal inundation and channel development. Unlike most studies, we put these physical metrics in terms of juvenile Chinook by constraining our inundation model to outmigration season (Mar – Aug) and those tidal depths supporting juvenile Chinook (\u3e 0.4 m). We used these criteria, verified by presence of juvenile salmonids in three restored and two reference tidal channels, to measure the change in opportunity potential from pre-restoration to post-restoration condition for juvenile Chinook to access and rear in the Nisqually estuary. We found landscape connectivity to be strongly tied to tidal height and increased throughout the estuary with dike removal. Tidal channel development was most rapid in the first and second year post-restoration; with channel outlets widening and deepening to accommodate restored tidal prisms. Chum salmon, natural origin Chinook and hatchery origin Chinook salmon accessed all three restored marshes within two years post-restoration, although responses varied among years, marshes and salmon species. These results suggest that the Nisqually Delta restorations are providing increased rearing opportunity for juvenile salmon

Progressing from multidisciplinary to interdisciplinary restoration science: monitoring and applied studies on the Nisqually River Delta

Restoration science is often described as an ultimate test of ecological theory; assessing the value of restoration actions is challenged by difficulties in measuring complex interactions between restored physical processes and the response of biological resources. Yet, demonstrating the value of restoration is a key to sustaining future public investment, especially in light of uncertainty of future climate change effects. At the Nisqually River Delta, a restoration partnership between the U. S. Fish and Wildlife Service Nisqually National Wildlife Refuge (Refuge), the Nisqually Indian Tribe (Tribe), and Ducks Unlimited culminated in re-established tidal flow to 360 ha of historic floodplain and delta representing the largest estuarine restoration in the Pacific Northwest. Restoration of this large delta was expected to result in a substantial improvement in ecological functions and services in southern Puget Sound. The goal of our scientific team, led by the U. S. Geological Survey (USGS) for the project partners, was to assess the biophysical response to restoration. Science objectives were built into a monitoring framework to include hydrodynamics, geomorphology, sedimentation and nearshore processes with vegetation, invertebrate food resources, waterbird, and fisheries. Our science partners included the U. S. Geological Survey, Refuge, Tribe, non-governmental organizations, and universities representing several disciplines. Funding the science was challenging, since as with most wetland restoration projects, adequate funds are rarely included in costs. Instead, the managers and scientists worked together to raise funds through special funds and competitive grants including addressing climate change. With this funding model, a major challenge for the team was communicating and sustaining a vision to make separate multidisciplinary efforts into unified interdisciplinary science. Here, we use lessons learned from early results of the Nisqually River Delta restoration to discuss restoration science in planning processes, funding costs and approaches, monitoring versus applied studies, and advancing interdisciplinary findings from multidisciplinary efforts