SGER: Postfire Community Structure and Species Area Relationships

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This proposal is to request funds from the SGER program for research to study postfire plant response in chaparral shrublands burned during the massive fires this summer in Arizona and New Mexico. There is an urgency to this request because the work needs to be initiated this September. While extensive research has been conducted on the immediate postfire response of California chaparral, relatively little is known about these Southwestern U.S. chaparral stands. Californian chaparral has a unique ephemeral postfire flora comprising hundreds of mostly annual species derived from long-lived seed banks, the vast majority of these species are endemic to California. There is reason to believe the immediate postfire response is different in Arizona and New Mexico chaparral stands, and is dominated by herbaceous and woody perennials.These Southwest U.S. chaparral stands are of interest for what they can potentially tell us about causal factors behind species area relationships. Prior studies show annual dominated California shrublands exhibit very different species area relationships then perennial dominated Australian shrublands. There is evidence that community structure revealed by very different dominance-diversity curves play a role in the species area relationship and life form differences are hypothesized to be the primary determinate of species area relationships. The Southwestern U.S. chaparral stands will provide an independent test of this idea. An additional dimension of this project is the predicted differences in functional type response to fire in these summer rain shrublands relative to summer drought shrublands in California. The competitive relationships of the two main disturbance functional types, reprouters vs. seeders are predicted to differ between these two climate regimes.