Susan L. Sargeant’s scientific contributions

Restoration projects have an uncertain outcome because of a lack of information about current site conditions, historical disturbance levels, effects of landscape alterations on site development, unpredictable trajectories or patterns of ecosystem structural development, and many other factors. Because of these uncertainties, project costs can rise dramatically in an attempt to come closer to project goals. All of the potential sources of error can be addressed to a certain degree through adaptive management. The first step is admitting that these uncertainties can exist, and addressing as many of the uncertainties with planning and directed research prior to implementing the project. The second step is to evaluate uncertainties through hypothesis-driven experiments during project implementation. The third step is to use the monitoring program to evaluate and adjust the project as needed to improve the probability that the project will reach its goal. The fourth and final step is to use the information gained in the project to improve future projects. A framework that includes a clear goal statement, a conceptual model, and an evaluation framework can help in this adaptive restoration process. Projects and programs vary in their application of adaptive management in restoration, and it is very difficult to be highly prescriptive in applying adaptive management to projects that necessarily vary widely in scope, goal, ecosystem characteristics, and uncertainties. One project, which included directed research and site assessments, resulted in successful restoration of seagrasses near a ferry terminal in Puget Sound and illustrates how an adaptive management process can assist in improving the outcome of small projects. We recommended that all restoration programs be conducted in an adaptive management framework, and where appropriate, a more active adaptive management approach be applied.

The derelict Thomas Oil Dock on state tidelands in Port Townsend, Washington, was redesigned for the Northwest Maritime Center by a committee including marine scientists, architects, engineers, educators, regulators, and user groups. The committee's objectives were to create a ''demonstration dock'' using the best-available technologies and design features to restore nearshore habitat functions, particularly for threatened fisheries resources, while accommodating the unique requirements of the educational facility to house vessels ranging from historic tall ships to sea kayaks. A key nearshore habitat restoration goal was to reduce fragmentation of eelgrass where shade from the existing dock inhibited growth, by improving conditions with a new dock design and transplanting eelgrass to connect existing patches. Ecological conditions were evaluated through diver surveys; mapping existing eelgrass, macroalgae, and substrates; and review of controlling factors. Data on the attenuation an d diffusion of photosynthetically-active radiation (PAR) was collected and evaluated relative to eelgrass light requirements. Potential shade impacts of existing and alternative dock designs and materials were modeled. Key design features to improve habitat functions included the installation of reflective material under the dock to increase the incidence of PAR at the substrate level, reduction in the number of piles and associated shade impacts through the use of steel piles instead of wood, increase in the length of the trestle to 286 to move the greatest area of overwater structure beyond the range of eelgrass, and the use of grating in strategic locations to reduce the potential of a light/dark barrier to fish passage.

Large overwater structures have often been cited as potential migratory barriers and areas of increased predation for juvenile salmon migrating along shallow shoreline habitats, although conclusive evidence has not been demonstrated to date in situ. To help resolve this issue, Washington State Ferries (WSF) sponsored directed research to determine whether WSF terminals affect predation on juvenile salmon. We used a combination of standardized surveys, stomach content analyses, and new observational technologies to assess fish, avian, and mammal predation on salmon fry at ferry terminals and paired reference sites during periods of pre- (early April) and peak (May) outmigration. We observed no significant aggregation of potential bird or mammal predators at six ferry terminal study sites. Few potential fish predators were documented in SCUBA surveys, beach seines, or with a Dual frequency IDentification SONar (DIDSON) camera at Mukilteo, our single underwater study location. Only one instance of salmon predation by fish (staghorn sculpin ? Leptocottus armatus) was confirmed, and this was at the corresponding reference site. A tiered protocol (Minimum/ Recommended/ Preferred actions) was developed for assessing potential predation at other overwater structures. Likewise, recommendations were developed for incorporating design features into WSF terminal improvement projects that could minimize future impacts.

Environmental factors that influence annual variability and spatial differences (within and between estuaries) in eelgrass meadows (Zostera marine L.) were examined within Willapa Bay, Washington, and Coos Bay, Oregon, over a period of 4 years (1998–2001). A suite of eelgrass metrics were recorded annually at field sites that spanned the estuarine gradient from the marine-dominated to mesohaline region of each estuary. Plant density (shoots m−2) of eelgrass was positively correlated with summer estuarine salinity and inversely correlated with water temperature gradients in the estuaries. Eelgrass density, biomass, and the incidence of flowering plants all increased substantially in Willapa Bay, and less so in Coos Bay, over the duration of the study. Warmer winters and cooler summers associated with the transition from El Niño to La Niña ocean conditions during the study period corresponded with this increase in eelgrass abundance and flowering. Large-scale changes in climate and nearshore ocean conditions may exert a strong regional influence on eelgrass abundance that can vary annually by as much as 700% in Willapa Bay. Lower levels of annual variability observed in Coos Bay may be due to the stronger and more direct influence of the nearshore Pacific Ocean on the Coos Bay study sites. The results suggest profound effects of climate variation on the abundance and flowering of eelgrass in Pacific Northwest coastal estuaries.

Scientific diving can provide unique information for addressing complex environmental issues in the marine environment and is applied to a variety of increasingly important issues throughout Puget Sound, including habitat degradation, endangered species, biological availability of contaminants, and the effects of overwater structures and shoreline protection features. The Pacific Northwest National Laboratory, Battelle Marine Sciences Laboratory uses trained scientific divers in conjunction with advanced technologies to collect in-situ information best obtained through direct observation and requiring minimal environmental disturbance. For example, advances in underwater communications allow divers to discuss observations and data collection techniques in real time, both with each other and with personnel on the surface. Other examples include the use of Dual frequency IDentification SONar (DIDSON), an underwater camera used to capture digital images of benthic structures, fish, and organisms during low light and high turbidity levels; the use of voice-narrated underwater video; and the development of sediment collection methods yielding one-meter cores. The combination of using trained scientific SCUBA divers and advanced underwater technologies is a key element in addressing multifaceted environmental problems, resulting in a more comprehensive understanding of the underwater environment and more reliable data with which to make resource management decisions.

To address resource agency concerns about potential impacts of ferry terminal expansion on habitat functions and resource use of nearshore areas, the Pacific Northwest National Laboratory, in partnership with the Washington State Department of Transportation, conducted field trials with several products that promote light passage through dock structures. Photosynthetically active radiation (PAR) measurements were compared with known minimum requirements for survival of eelgrass, Zostera marina, which provides critical habitat for the federally listed chinook salmon, Oncorhynchus tshawytscha. PAR measurements were also related to what is known about the effects of light on juvenile salmonid feeding and passage under overwater structures. In general, the products predicted to provide the most to the least light were the grating, SunTunnel, metal halide greenhouse light, and prisms. All the light technologies tested could provide enough light for eelgrass underneath a ferry terminal, though multiples of some devices would be required. Because less light is required for fish to feed than for photosynthesis, any of the products would provide enough light for juvenile salmon to feed under the structure. The number and placement of these devices could be arranged to maximize light penetration for particular purposes in different situations.