Cheadle Center for Biodiversity and Ecological Restoration

Arenaria paludicola is a critically endangered California wetland plant. Only one original population exists at Oso Flaco Lake in San Luis Obispo County, in additionto some out plantings that have been established. Current knowledge of the idealhabitat and conditions for Arenaria paludicola is limited, making it difficult to identify sites that would be ideal for new out plantings to preserve the species.This study investigates the ability of Arenaria paludicola to grow in five soil types to evaluate the viability of a natural seep site located on UC Santa Barbara’scampus as a location for planting a new population. In addition, the seep waterwas used on two replicates of the experiment to determine if the water itself issuitable for Arenaria paludicola. The soils that showed the most growth over the course of the study were coarse commercial sand mixed with compost andpotting mix, with the campus loam showing no growth, and the heavy clay andfine sand soils native to the site showing the least growth and most death. Inaddition, the seep site plantings uniformly declined in health and died, showingthe seep water is unsuitable. From this we can conclude that Arenaria paludicola prefers coarser sand and potting mix to finer grained sandy soils and clays, andthat the seep site is unlikely to support a population of Arenaria paludicola.