This study focuses on understanding how restored tidal wetlands with different physical configurations function as refuge and rearing habitat for fishes, including native and imperiled species such as delta smelt and juvenile Chinook salmon. This research will assess the spatial distribution of predation risk as it varies within and across tidal wetlands. The proposed research will generate a statistical model that helps predict predation outcomes from various restored tidal wetland designs and channel configurations. This will be a powerful tool for managers to forecast how proposed habitat restoration or water management actions may impact native fish populations.
Pesticide and nutrient inputs from human activities are present in the Sacramenot-San Joaquin Bay-Delta, but the impact of these stressors together on algae is not well known. This research will examine the impacts of herbicides and nutrients on the growth and stress responses of phytoplankton and cyanobacteria present in the San Francisco Estuary. The algae in the delta are diverse with critical ecological effects, ranging from toxin-producing cyanobacteria that form hazardous algal blooms to benthic diatoms and green algae that make up the bulk of the aquatic food web. Contaminants and herbicides can cause changes in algae cellular health which may impact population growth. Understanding algal sub-lethal stress responses will improve our understanding of stressors on the bay-delta food web and bloom formation.
The goal of this research is to better understand how climate change will affect fishes with different life histories and habitat associations across the San Francisco Estuary. Existing datasets will be incorporated in synthetic analyses and cutting-edge statistical models to identify fish community responses to climate, flows, and habitats along the estuarine salinity gradient. This synthesis-science project will use rich long-term datasets that have been collected by Bay-Delta researchers for decades that will then be analyzed in a reproducible and open science framework. It will also support efforts by the Interagency Ecological Program’s Climate Change Project Work Team.
The Environmental Monitoring Program (EMP) began in 1975 to conduct baseline and compliance monitoring of water quality, phytoplankton, zooplankton, and benthic invertebrates in the San Francisco Bay-Delta estuary. This monitoring program was designed to track the impact of water diversions to the State Water Project (SWP) and Central Valley Project (CVP) on the Bay-Delta. In the decades since, EMP scientists have monitored these constituents at fixed and floating stations throughout the estuary and ensured compliance with state and federal mandates such as Water Right Decision 1641 (D-1641). In the years and decades since its inception, EMP has become one of the cornerstones for scientists' and managers' understanding of the pace and pattern of change in this critical ecosystem. By sampling water quality and biological communities concurrently, EMP has created a dataset that is uniquely useful in better understanding causal connections between physical, biological, and biogeochemical processes.
The Environmental Monitoring Program (EMP) has conducted the Zooplankton Study since 1972 to better assess trends in the lower trophic food web in the San Francisco Bay-Delta estuary. The study also detects and monitors zooplankton recently introduced to the estuary and determines their effects on native species. Under the auspices of the Interagency Ecological Program for the San Francisco Estuary and mandated by Water Right Decision D-1641, the EMP Zooplankton Study is part of the Environmental Monitoring Program and is conducted by the California Department of Fish and Game (CDFW), California Department of Water Resources (DWR), and the United States Bureau of Reclamation (USBR).
Tradeoffs among objectives in natural resource management can be exacerbated in altered ecosystems and when there is uncertainty in predicted management outcomes. Multicriteria decision analysis (MCDA) and value of information (VOI) are underutilized decision tools that can assist fisheries managers in handling tradeoffs and evaluating the importance of uncertainty. We demonstrate the use of these tools using a case study in the Sacramento River, California, U.S.A., where two imperiled species with different temperature requirements, winter-run Chinook Salmon (Oncorhynchus tshawytscha) and Green Sturgeon (Acipenser medirostris), spawn and rear in the artificially cold Shasta Dam tailwater. A temperature-control device installed on Shasta Dam maintains cool water for Chinook Salmon; however, uncertainties exist related to the effects of temperatures on the spawning and rearing of both species. We consider four alternative hypotheses in models of early life-stage dynamics to evaluate the effects of alternative temperature-management strategies on Chinook Salmon and Green Sturgeon management objectives. We used VOI to quantify the increase in management performance that can be expected by resolving hypothesis-based uncertainties as a function of the weight assigned to species-specific objectives. We found the decision was hindered by uncertainty; the best performing alternative depends on which hypothesis is true, with warmer or cooler alternative management strategies recommended when weights favor Green Sturgeon or Chinook Salmon objectives, respectively. The value of reducing uncertainty was highest when Green Sturgeon was slightly favored, highlighting the interaction between scientific uncertainty and decision makers’ values. Our demonstration features MCDA and VOI as transparent, deliberative tools that can assist fisheries managers in confronting value conflicts, prioritizing resolution of uncertainty, and optimally managing aquatic ecosystems.
To support management planning in Suisun Marsh, this project is developing a body of science and tools to understand past, present, and potential future changes to the Marsh’s ecological patterns, processes, and functions. This project builds on SFEI’s prior work in the Delta, extending historical ecology mapping, landscape change studies, and the Landscape Scenario Planning Tool to cover Suisun's historical and present-day landscapes. Through spatially explicit representations of the historical function and condition of the marsh and analyses of landscape metrics, this project is evaluating changes over time in landscape support for ecosystem functions and services in Suisun. In order to incorporate diverse perspectives into planning resources, project activities include engagement with local tribes and community members to understand community interests, priorities, and uses of the Marsh. Findings will be shared through a report and article for both technical and general audiences, and spatial analyses and data layers will be made available through the Landscape Scenario Planning Tool.
