Jaymee Marty, The Nature Conservancy
California's Central Valley grasslands represent one of the most invaded ecosystems in the United States with the cover of non-native plant species often exceeding 85 percent. Vernal pools are seasonal wetlands that occur within these grassland systems and serve as a refuge for native species that have adapted to the pools' seasonally flooded and desiccated environment. More than 90% of the remaining vernal pool grasslands in California are currently and have historically been grazed by livestock. Historically, grazing was removed from vernal pool grassland properties as non-profit organizations and governmental agencies acquired them for conservation purposes. I am conducting an experiment to evaluate the long-term effects of grazing exclusion on vernal pool flora and fauna. Three years of grazing removal led to a significant reduction in vernal pool inundation and decreased diversity of native plant species and invertebrate taxa. These initial results indicate that grazing plays a major role in maintaining the function and diversity in this ecosystem.