Intellectual merit: Globally, the diversity of plants and animals is highest in regions where rainfall and solar energy are abundant, which yields high rates of carbon capture via photosynthesis termed primary productivity. This project will analyze a previously unexamined aspect of this pattern, namely, how productivity affects the degree to which plants are specialized on different soils, which can drive the variation in species composition among different locations. In productive climates, this project will test the hypothesis that plant communities on different soils will be highly distinct because intensified competition leads to narrower soil niches, whereas in colder or more arid climates less distinctiveness of plant communities across soil boundaries is predicted. These predictions will be tested by comparing plant communities on chemically unusual soils such as serpentine, limestone, and dolomite, to those on nearby normal soils, across gradients of high to low rainfall in California and the Ozarks. To better understand the mechanisms for the observed patterns, experimental manipulations of rainfall and plant competition in neighboring serpentine and non-serpentine plant communities in California will be conducted. This research is important because plant species and communities endemic to particular soils are important contributors to global botanical diversity. Our results will help understand how climate controls plant diversity, plant community composition, and the degree to which plant communities are affected by biological invasions.
Broader impacts: A graduate student from an underrepresented group and several undergraduates will be trained with this award. Data will be made available to researchers, agency scientists, and nonprofit environmental groups through the data archives of the Knowledge Network for Biocomplexity (knb.ecoinformatics.org) and the UC Natural Reserve System Data Registry.
