Implementation of vegetation classification for restoration and management of Californian grasslands

Background/Question/Methods Californian natural low elevation grassland is an extinct vegetation type. Remaining grasslands, which were not converted to agriculture or residential areas, are heavily dominated by introduced species that displaced natives partially or completely. Lack of knowledge about pristine grasslands makes it difficult to define management and restoration objectives and measure success of restoration efforts. The objective of this study was to reconstruct floristic composition of California grasslands, to understand former diversity grassland types, and to provide guidelines for their management and restoration. We sampled >300 plots (100 m² each) in 10 locations throughout the Central Valley. Using TURBOVEG, JUICE, TWINSPAN, and PC-ORD software for data analysis followed by Braun-Blanquet method of vegetation classification, we distinguished 14 grassland types defined in the presence of its own set of diagnostic native species. These types were used to define targets for ecological restoration.

Results/Conclusions Our results have been brought to the attention of restoration and conservation ecologists to recognize the broad range of plant communities that once constituted an extensive California prairie. These results shifted common focus on restoration of native bunchgrasses toward restoration of diversity of native forbs. We will discuss: (1) application of vegetation classification for ecological reconstruction and introduce a method of floristic analysis that has not yet been used for these purposes; (2) report results of the reconstruction of floristic composition of native species in grasslands in California Central Valley and discuss their relationship to oak woodlands and riparian forests; (3) explain how classification was used to predict which species should be reintroduced into existing floristically poor grasslands; (4) and demonstrate examples of reintroduction that enhanced the native species component in modern grasslands.