Upper Long Bar Pre-Project Vegetation Monitoring

The Upper Long Bar Salmonid Rearing Habitat Enhancement Project is dedicated to enhancing the habitat conditions for spring-/fall-run Chinook salmon and Central Valley steelhead along the lower Yuba River. By strategically altering the hydrology of a degraded gravel bar, we aim to create optimal rearing environments for these crucial species. This transformation will involve adjustments such as heightened inundation frequency and reduced groundwater depth, changes that are expected to have a significant impact on the local plant ecosystem.

Prior to implementing these modifications, thorough vegetation surveys were conducted to establish baseline data on the diversity and abundance of both native and non-native plant species.

In late April of 2024, SYRCL staff (and dogs!) conducted vegetation surveys at Upper Long Bar to collect data on plant community composition before construction that is anticipated for summer 2025. These data will establish a baseline to help us determine how cover and community may shift after implementation.

Five roughly 100m transects were established across the Upper Long Bar project area perpendicular to the flow path using desktop methods, and then fitted in the field as necessary. Transects were selected to intersect with the maximum number of planned habitat features. Three to six 4m squared plots were placed along each transect in areas where change is hypothesized to occur (i.e. the edge of a designed alcove) for a total of 18 plots.

Total growth cover of vegetation was estimated for each plot and all plants contributing to cover were identified down to species. Where species could not be determined in the field, samples were carefully documented and collected for identification in the office using a dissecting scope.

In total, 36 unique species were observed during vegetation surveys. Of plots surveyed, roughly half of cover was attributed to non-native species and the other half to native species.