CAREER: Integrating biochemical, physiological and morphological responses of plants to changes in water availability

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This research addresses how leaf, stem and root traits collectively influence organismal responses to different precipitation scenarios across multiple species in a Mediterranean-climate ecosystem. Precipitation in arid and semi-arid environments can vary strongly within and across years and plant fitness can depend on rapid or efficient utilization of water during these events. Plant species adapted to arid systems possess numerous leaf, stem and root traits that serve to minimize water stress, but it remains unclear whether these water conservation traits limit a plant's ability to rapidly respond to precipitation events and how water acquisition and conservation traits correspond to plant fitness. The proposed research is organized around two questions: (1) is there a trade-off between the ability to respond to sudden changes in water availability and a water conservation strategy, and (2) how do traits pertaining to water acquisition and conservation correlate with plant fitness and how does this depend on the magnitude and frequency of precipitation? These questions will be examined in four annual and six perennial species from a southern California coastal sage scrub community. Understanding how biochemical, morphological and physiological processes result in integrated organismal responses to environmental variation will improve predictive models of community response to climate change. Mediterranean-climate ecosystems are among the regions of the world most likely to be affected by climate change and the proposed work will collect critical information needed to restore these unique, threatened ecosystems. For example, understanding how species use water under a variety of precipitation scenarios may improve restoration efforts in systems invaded by exotic plant species by allowing resource managers to identify native species that use resources in a similar way, which may increase community resilience to invasion. This CAREER proposal represents a fully integrated plan of research and education though supervised and independent research (undergraduate, high school summer internships) and courses at the undergraduate and high school level. The study will be conducted at a small, undergraduate institution and will provide four undergraduate researchers per year with opportunities to enhance research, analytical and communication skills. Most of these students will continue into graduate programs or pursue careers in ecology or plant biology. Students from four upper-division biology courses will be directly involved in collecting and analyzing data from the proposed field experiment. High school science students from traditionally underrepresented groups will participate in weekly meetings at the PIs lab to set up a greenhouse experiment and collect and analyze data. High school students will also participate in weekend field trips and have the opportunity to conduct summer internships. The research grant will also help to establish long-term plots for the young female professor who is serving as the PI. The PI will engage the scientific community, resource managers and the general public through public lectures, local restoration activities, and continued collaborations with resource managers at the Irvine Ranch Conservancy.