Classification of California vernal pools: Implication for conservation and restoration

We have recently completed the analysis of vernal pool vegetation throughout California, a database consisting of 700 pools and more than 2200 plots (each 10 m square).  The plots fell within one class, three orders, and several dozen associations, based on complete floristic composition.  The classification addressed phenological variability of species presence/abundance during a single growing season and variation from year to year due to weather conditions. Most associations have relatively narrow ranges, restricted to one or two vernal pool regions. We showed that whole vernal pools typically consist of a complex of plant communities, and these are floristically, topographically, and geographically autonomous.  The presence of some rare species was strongly correlated with particular associations.  The implications of these findings are that conservation and restoration activities must be locally focused.  If only one or two vernal pool preserves were to be created in California, they would contain only a small number of all possible association types.  We propose new criteria for measuring restoration success that focus on preserving community diversity (beta diversity) and that the degree of success be measured by the floristic similarity between created pools and those local pools that were lost (rather than by the presence of some common, California-wide taxa).  Other proposals address the way in which reference pools should be chosen so that collectively they represent the diversity of plant communities to be taken.  This classification contributes understanding about the remaining diversity of vernal pool vegetation, information that will be used to prevent further loss.