The California chaparral and similar communities around the world have played a pivotal role in the development of plant ecology as a science. The ecological similarity of distantly related species in these communities has long served as a paradigmatic example of convergent adaptation. In addition, the study of ecological differences between species has played a central role in elucidating alternative strategies related to abiotic stress and disturbance. The study of ecological variation has focused on two features: i) water relations and drought tolerance, in relation to rooting depth and habitat distribution, and ii) contrasting life history strategies related to regeneration following fire. The first objective of this study is to examine the relationships between photosynthetic characteristics, drought tolerance, and fire-regeneration traits in a broad comparative study of over 30 species from three sites ranging from northern to southern California. The second objective of this project is to integrate these ecological studies with the rapidly expanding knowledge of phylogenetic relationships among plant species to test whether the similarities and differences among these species represent local adaptations to the chaparral climate, or older characteristics which then led to the assembly of the current community.
This project represents the first attempt to assess the contributions of a large number of physiological and life-history traits to the identification of functional groups in woody plant species. The identification of functional groups is a critical step in understanding the mechanisms of coexistence in diverse plant communities, and in assessing the potential responses of different species to changing fire regimes and other environmental conditions. Furthermore, this project will finally provide a test of the long-standing paradigm of convergent adaptation in chaparral-like communities.
