This project aims to quantify the impacts of common reed (Phragmites) invasion on community structure and ecosystem function during early stages of tidal restoration in wetlands. The study will focus on the Tule Red Tidal Restoration site in Suisun Marsh. The research aims to produce a conceptual model that will describe habitat structure, invertebrate communities, and predator use of wetlands affected by Phragmites invasion. The conceptual model resulting from this study will guide future predictions of wetland response to invasion and to develop mitigation strategies. Data collected will also support food web models and the understanding of invasive plants as stressors, as well as foster translational science to the management community.
We propose to use a unique toolbox combining genetic and isotopic markers to 1) Assess the genetic diversity of Central Valley spring-run Chinook salmon (Oncorhynchus tshawytscha; CVSC), 2) Identify the juvenile life history diversity and the importance of natal versus non-natal and in-channel versus off-channel habitats, 3) Evaluate the connection between genetic diversity and the expression of life history diversity in each CVSC population, and 4) Investigate the response and resilience of CVSC populations, with various levels of genetic and phenotypic diversity, to changes in habitats and environmental conditions such as droughts and floodplain reconnection.
We will combine otolith, eye lens, and genetic tools to study the phenotypic diversity and genetic origins of returning adult spawners from spring-run Chinook Salmon spawning grounds across the entire ESU in 2024 and 2025. All individuals will first be assigned to their run type using genome wide sequencing and newly developed SHERLOCK methods. Otolith and eye lens isotope methods will then be used to characterize the juvenile migratory strategy diversity, rearing habitat use, natal origin and adult age structure of each CVSC population. These data will be synthesized to evaluate the resilience of CVSC populations with various biocomplexity levels to a changing climate and landscape.
Invasive submerged aquatic species (SAV) greatly impact habitat for endangered species in the Delta. In the past decade, we have seen a huge increase in SAV cover and an influx of new invasive species like ribbonweed. This study will build species distribution models (SDM) for SAV using predictors such as water speed, depth, salinity from the UnTRIM hydrodynamic model, turbidity derived from Sentinel-2 and temperature derived from ECOSTRESS satellite imagery. The SDMs will be used to study the effect of flow management actions and restoration activities on SAV distribution. SAV community data collected in the field (available on EDI) will be analyzed to study if the SAV community composition has changed from 2007-08 to present time. The same dataset will be used to explore if the SAV SDM can be refined based on species presence data to see if there are significant differences in SDMs of individual SAV species.
Invasive aquatic vegetation has been identified as a major concern in the IEP Science Strategy document and a topic meriting more study. Assessing the effects of flow alteration management actions on the Delta is also a recommended key topic of research. This study furthers both these objectives. It complements ongoing projects such as the water primrose ecoengineering project (PEN #348), which is similarly building an SDM for Ludwigia spp., determining plant characteristics that enable Ludwigia invasion and mapping invasion risk for the remnant Delta marshes. The work also builds off the conclusions of the Sentinel project which mapped the temporal phenological signal of SAV in the Delta. The results of this study will help design restorations to be more resistant to invasion, plan for climate change impacts, and predict invasion risk in Delta regions that are being reconnected tidally to the Delta waterways network through current and future restoration projects.
