Fire-driven alien invasion in a fire-adapted ecosystem

摘要: Disturbance plays a key role in many alien plant invasions. However, often the main driver of invasion is not disturbance per se but alterations regime. In some fire-adapted shrublands, community highly resilient to infrequent, high-intensity fires, changes fire regime that result shorter intervals may make these communities more susceptible This study examines several wildfire events resulted short California chaparral shrublands. one study, we compared postfire recovery patterns sites with different prefire stand ages (3 and 24 years), another had burned once four years twice this period. The population size dominant native shrub Adenostoma fasciculatum was drastically reduced following 3-year relative 24-year sites. much greater cover significantly lower diversity than separate repeat fires apart on same showed annual species increased after second fire, annuals far outnumbered annuals. Aliens included both grasses forbs were negatively correlated woody cover. Native regenerated well first declined obligate seeding extirpated from two by fires. It concluded shrublands are vulnerable regime, can lead loss put trajectory towards type conversion an herbaceous system. Such proportion natives non-natives, functional types deeply rooted shrubs shallow forbs, frequency due increase fine fuels, carbon storage.