The goal of this research was to better understand how climate change will affect fishes with different life histories and habitat associations across the San Francisco Estuary. Existing datasets were 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 used rich long-term datasets that have been collected by Bay-Delta researchers for decades in a reproducible and open science framework.
The team investigated how freshwater flow and sea surface temperature impacted juvenile fish species in the lower and upper estuaries and found differing tolerances. Additionally, they looked at both the biological and spatial structures within the communities and concluded preserving diversity is key to stabilizing juvenile fish recruitment in response to changing environmental conditions. Even in highly dynamic environments such as estuaries, climate change will likely result in winners and losers among species. With an increase in the frequency and duration of drought and marine heatwaves, estuaries may become less hospitable to species that are environmental specialists, such as freshwater or cool water dependent species. This may lead to lower recruitment success. Ultimately, climate change may negatively affect species persistence, food web dynamics and ecosystem function.
A team at UC Davis (Dr. Mark Lubell, Dr. Gwen Arnold, PhD Candidate Kyra Gmoser-Daskalakis) is conducting social science research on wetland restoration in the California Bay-Delta as part of a larger, interdisciplinary project on wetland restoration across multiple University of California campuses and national labs ("Coastal Wetland Restoration a Nature Based Decarbonization Multi-Benefit Climate Mitigation Solution"). First, the project is conducting social network and spatial analysis using the EcoAtlas project database to examine drivers of wetland restoration investment in the Bay-Delta from the 1980s to now. Second, case studies of individual restoration projects and interviews with 40+ restoration project partners examines barriers to the restoration implementation and perceptions and goals of multi-benefits among interested parties. Preliminary results have been shared at the State of the Estuary and Bay-Delta Science Conferences in 2024. See https://wetlands.ucsc.edu/index.html for more information.
Managing California’s water supply is complex, requiring careful coordination to ensure sustainability, water quality, and the protection of public and environmental health. In the Sacramento–San Joaquin Bay-Delta, hundreds of datasets from studies and monitoring programs are used to assess conditions and inform key operational decisions. However, these datasets are often fragmented across agencies and stored in inconsistent formats, making it time-consuming for analysts and researchers to locate and use the data effectively.
This project aims to enhance the Bay-Delta Live (BDL) data management platform (www.baydeltalive.com) by integrating datasets from the California Department of Water Resources’ Water Data Library (WDL). The primary focus is on water quality and environmental monitoring data. By streamlining access to these resources, the project will improve the discovery, retrieval, and analysis of water-related datasets across multiple sources.
Key outcomes include:
This work will support more informed decision-making and help ensure the long-term safety, reliability, and ecological integrity of California’s water resources.
The foundation of conserving a species is monitoring its abundance and habitat. This proposed work has three objectives which will help monitor green sturgeon abundance and understand green sturgeon habitat selection. These objectives build on 12 years of work to support the recovery of green sturgeon. The first objective is to continue the annual green sturgeon spawner census, while also improving our methods. This census is the main piece of information used in monitoring and assessing the Delta resident green sturgeon population. The second objective is to assess spawner site selection and habitat use which will help better understand sturgeon environmental needs so that restoration can better target those needs. The third objective is to assess the relationship between spring flow rates, temperature, and number of spawners observed, which will help managers better understand sturgeon flow cues and improve the accuracy of our spawner census.
Invasive aquatic vegetation (IAV) is a threat to aquatic ecosystems worldwide, leading to a major loss of biodiversity and extensive damages and costs to human uses of those ecosystems. The Sacramento-San Joaquin River Delta (the “Delta”) is the hub of California’s water system, supporting over 35 million water users and a $54 billion agricultural industry. The Delta reform act mandates management decisions meet both water supply needs while maintaining the ecological function of the system. The Delta is a global biodiversity hotspot, and the focal point of $750-$950 million in restoration. It has also been called one of the most invaded estuaries in the world. Over the past 15 years, submerged and floating IAV have more than doubled in extent, threatening water supply and ecosystem health of the Delta. There is mounting evidence that herbicide treatments are not effective, and that water management actions, and wetland restoration may be having huge impacts on IAV. This presents both a risk to increasing IAV, but also an opportunity to prevent and even effectively combat IAV through considered water management actions and better restoration planning, meeting the state’s co-equal goals of water security and Delta ecosystem conservation.
This project will meet the needs of multiple state agencies by advancing operational Earth observation-based monitoring program for community-level submerged aquatic vegetation (SAV) and genus-level floating aquatic vegetation (FAV) and modeling tools to enable the Delta management community to assess the effect of previous management actions on IAV and forecast the effects of future actions to inform multi-agency decision making. Specifically, this work will 1) Operationalize IAV class mapping using Sentinel-2 satellite imagery, 2) Finalize and validate species distribution Models (SDM) for SAV community and FAV at genus-level to assess the impacts of previous water actions on IAV and predict IAV distribution in future scenarios, 3) Co-design IAV-based performance metrics to inform future actions.
The proposed project fills a critical data gap in monitoring for state and federal agencies and stakeholders by implementing the first sustainable mapping effort for IAV. Monthly and seasonal estimates of SAV and FAV coverage will enable the Delta Stewardship Council to improve their performance metrics for evaluation of the Delta Plan and will help the Interagency Ecological Program assess whether management is meeting the co-equal goals for the Delta. Species distribution models will enable Department of Water Resources to evaluate how previous restoration flow actions have affected the spread and persistence of IAV and incorporate what they learn into future Structured Decision Making to better account for negative consequences of IAV when setting future restoration targets and implementing actions.
