Dimensions of Biodiversity

PROJECT SUMMARY INTELLECTUAL MERIT: While a spectacular variety of life is perhaps the most defining feature of our planet, loss of this biological diversity is one of the most pronounced forms of environmental change in the modern era. Researchers have made great strides in understand how changes in biodiversity impact essential biological processes, such as the efficiency by which ecological communities capture limited resources and produce new biomass. However, we still do not understand the mechanisms by which diversity affects the productivity and sustainability of ecosystems, or which dimensions of biodiversity matter most. We believe this is partly due to the fact that most prior work has been preoccupied with variation among species as our primary measure of biodiversity. But ‘species’ are little more than a form of packing for all the genetic, functional, and trait variation that influence the efficiency and metabolism of an organism, and these differences are themselves shaped by patterns of evolutionary history and common ancestry. If we want to understand the functional consequences of diversity loss, we must first understand the evolutionary processes that generate and maintain diversity at levels spanning genes to communities. Here we propose a collaboration that will integrate phylogenetics, genomics, and community ecology to test the hypothesis: Evolution leads to genetic differentiation among species that controls the strength of niche partitioning and, in turn, how efficiently communities capture the limited resources needed to produce biomass. Using a group of algae that are among the most widespread and ecologically important in lakes throughout North America, we will: 1. Create a new molecular phylogeny that can be used to test whether assemblages of freshwater planktonic green algae are more genetically diverse than predicted by chance. 2. Experimentally manipulate the evolutionary and genetic divergence of species to assess how these aspects of biological diversity control niche differences and community productivity. 3. Conduct transcriptome analyses to identify the genetic basis of niche differentiation among species, and relate these to the production of biomass by phytoplankton communities. BROADER IMPACTS: Conservation efforts have increasingly focused on maintaining the functions and services that ecosystem provide to society. We have argued that changes in the efficiency and productivity of ecosystems may be more pronounced for extinction of species who share distant common ancestors compared to those who share more recent common ancestors. If correct, it would plausible to use molecular phylogenies to prioritize conservation efforts in ecosystems that are too large (forests), too remote (ocean bottoms), or too endangered (threatened species) to perform biodiversity experiments. Our project will train 4 postdocs, 3 Ph.D. students, 8-12 undergraduates, and 4 high-school interns yr-1 on projects the cross the disciplines of genomics, phylogentics and ecology. To facilitate training at the interface of these areas, we will expand a popular 4-d workshop that PI Oakley has already developed to include modules on genomics (taught by Delwiche and his postdoc), phylogenetics (taught by Oakley and his postdoc), and community/ecosystems ecology (taught by Cardinale and his postdoc). This course will train 15-20 students yr-1 in emerging topics and techniques that link these three fields. The class will be open to students/postdocs internationally, and will rotate among the UCSB, U Mich, and U Maryland campuses. We have also proposed to develop two K-12 exercises as part of this grant that will broaden student’s appreciation for biological diversity in important freshwater habitats INTEGRATION: The very premise of our work is that evolutionary divergence influences levels of genetic diversification, niche partitioning, and the efficiency by which communities capture limiting resources and produce biomass. A key strength of our studies is that they not only link genetic, taxonomic, and functional aspects of biodiversity, they do so from the controlled, but contrived scales of laboratory experiments to the uncontrolled, but realistic scales of cross-continental biogeography. The team we have assembled is ideal for this work: Oakley is an expert in molecular phylogenetics, Delwiche is an expert on the genomics and taxonomy of green algae, and Cardinale is an expert on the community and ecosystems ecology of algal communities.