Abstract: In southern California, fuel breaks traverse through chaparral habitat and become invaded by non-native annual grasses which along with anthropogenic wildfire, pose direct threats to shrubland ecosystems. Thus, there is a need to balance the goals of wildfire management and the ecological impacts of fuel modification. Our goal is to understand how to reduce the ecological consequences of fuel modification by eco-engineering fuel breaks with native herbaceous species to limit the impacts of non-native species, reduce ignition risk, and support desired ecosystem functions.
In order to understand how native plant communities could differ in desirable ecological traits and fuel characteristics from the current vegetation that dominates fuel breaks, non-native annual grasses, we started a plot-scale restoration experiment in a fuel-modified habitat in the Los Padres National Forest, Santa Barbara, California. Plots were restored by either direct seeding a community of annual forbs, or by hand planting a community of bunchgrasses and perennial forbs. Control plots were established which contained non-native annual grass and forbs. Over three years, the different plant communities were monitored. Data included metrics for wildfire spread and ignition potential: live fuel moisture, fuel load, live:dead biomass, and litter depth; as well as ecological traits—invasion resistance and floral availability.
Native species communities retained live fuel moisture over the summer and created less litter, whereas the non-native community lost all live fuel moisture in early spring and generated more litter. Thus, the native communities would likely be more difficult to ignite and propagate fire. Therefore, these native herbaceous communities potentially created more favorable fuel conditions than the non-native community, giving creditability to using native species on fuel breaks to meet fuel management goals while supporting desirable ecosystem services.
