RAPID: Is postfire recruitment of chaparral shrubs constrained by local adaptation to soils (serpentine vs sandstone) or microclimates (north vs south slopes)?

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Fire plays a key role in the ecology of chaparral, or evergreen shrublands, an ecosystem unique to the five Mediterranean-climate regions of the world including California. Seeds of many chaparral plants germinate only in the year after a fire, and so the age, reproduction, dispersal potential, and community composition of chaparral plants are controlled by the infrequent occurrence of fire, typically once every 1-10 decades. Prescribed burns are seldom possible in Californian chaparral. What research has been done on the fire ecology of this ecosystem has been largely opportunistic, taking advantage of naturally occurring fires. More than 5,000 hectares of accessible public lands burned in 2008, creating a rare opportunity to examine whether three dominant chaparral shrub species are locally adapted to the sites on which they are found. Tests will be performed to determine if regeneration occurs only from seed produced on particular soil types (sandstone or serpentine) or on particular slope types (warm south-facing or cool north-facing), or whether seed produced in a particular habitat can successfully germinate and establish in other soil types or on slopes with different aspects. Results from this study will provide additional information for science-based management of chaparral ecosystems. This information will contribute to both the restoration of degraded chaparral and to the ability of resource managers to predict and plan for shifts in species distributions in response to climate change.