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.
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.
This project aims to characterize and quantify where detrital material (decaying plant matter) originates within wetlands, the composition of that material, and how export of detrital particles occurs. This project will combine powerful characterization tools and techniques that scale from molecules to ecosystems to assess spatial and temporal trends in particle sources, species and composition. Because restoration in the Sacramento-San Joaquin Delta will fundamentally alter particle distribution and food availability for aquatic organisms, this study will inform habitat restoration efforts and the revival of native fish populations. The tools developed and adapted for this project may inform management response during extreme conditions and climate events by helping to identify areas that may act as refugia for species.
The primary objective of this project is to develop alternative rearing methods for the critically endangered Delta Smelt, endemic of the San Francisco Bay Delta (SFBD). Current hatchery practices have struggled to overcome domestication effects in captive-reared fish, resulting in reduced fitness and lower survival rates when released into the wild. Additionally, the resource-intensive nature of Delta Smelt rearing and the associated costs present challenges to scaling up production. While the UC Davis Fish Conservation and Culture Laboratory (FCCL) has made significant strides in producing Delta Smelt for supplementation, meeting long-term population recovery goals will require more efficient and effective rearing methods. This project aims to improve post-release survival rates and overall fish production by exploring more naturalized and cost-effective rearing environments.
To achieve this, we will investigate the use of local impoundments (enclosed natural environments that provide more variable and realistic conditions) compared to traditional hatcheries for increasing Delta Smelt production and fitness. We will rear Delta Smelt in enclosures placed within these impoundments and compare key fitness-determining traits, such as survival, growth, temperature susceptibility, hypoxia tolerance, and antipredator behavior, to those of fish reared under controlled conditions at the FCCL. Additionally, we plan to transfer practices developed in other successful fish supplementation programs (e.g. Razorback Sucker and Rio Grande Silvery Minnow) and develop methods for natural spawning within these impoundments by introducing spawning substrates and closely monitoring spawning activity during the natural season.
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.
