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.
Water primrose (Ludwigia spp.) is a highly invasive, non-native floating macrophyte in the Delta. In recent years, water primrose has extended its niche into marsh habitat, causing extensive mortality of marsh macrophytes including tules and cattails. The goal of this project is to determine whether the growth strategy of water primrose, its allelopathic properties, or factors related to plant community structure are the cause of marsh loss following water primrose invasion in the Delta. Part of this study will identify and map the marshes most vulnerable to loss and quantify the spatial trajectory of marsh loss during the past 15 years. The ultimate benefit will be an improved understanding of the water primrose invasion processes in the Delta, which can be used to prioritize herbicide treatment of this highly invasive plant in marshes most vulnerable to invasion and with the highest habitat value.
Objectives:
Observations of individual and population dispersal of delta smelt are essential for improving models that can inform management strategies potentially improving movement into favorable areas or reducing movement into areas of poor habitat quality and risk of pumping loss. However, delta smelt movement patterns are largely unknown. Pacific Northwest National Labs has developed a much smaller Juvenile Salmon Acoustic Telemetry System (JSATS) tag, called the "Shad tag." Recent experiments suggest these tags can be successfully implanted in delta smelt without having significant, negative effects on individual condition and swimming behavior. The next step to determine if the newest technology may provide a tool for acoustic observation of fish dispersal over small spatial scales. Filling this data gap is important because changes in delta smelt spatial distribution (i.e., movement or dispersal) play a significant role in the management and recovery of the species.
This project includes two years of field-based experiments necessary to move this technology into the field. The existing San Francisco Estuary's JSATS array was designed to detect larger, more powerful tags and may not be as effective at detecting the smaller, less powerful tags. Therefore, first, we will test the detectability of the Shad tag by the existing JSATS array and explore detectability at potential locations for new receivers at delta smelt-relevant locations. Secondly, we will design and deploy a 3D positioning array to test performance of such an array in upper San Francisco Estuary habitats. Finally, we will conduct several small releases of delta smelt implanted with the new Shad tag to assess the capacity of the JSATS receiver arrays to detect and position live fish. This feasibility study will lay the groundwork for the development of a receiver array and post detection signal processing algorithm to detect delta smelt tagged with Shad tags in later phases of the project.
