Collaborative Research: The Roles of Community Assembly and Consumer Impacts in Shaping Ecosystem Function

San Diego State University Foundation, San Diego CA

Investigators

Abstract

Ecosystems provide important services such as supporting biodiversity and providing clean water and air for people. These functions are driven by the plants and animals living in that ecosystem and determined by the characteristics of those species—their “functional traits.” When new species arrive in an ecosystem, or they leave or die off, it changes the number of species and the combination of functional traits present, so ecosystem functions can change as well. Knowing which species are most likely to arrive or die off, and how they contribute to ecosystems, can help ecologists predict how benefits to people will change over time. Such information is especially important for predicting how ecosystems will respond to disturbances like climate change, and for helping to understand how we can best restore damaged ecosystems. This project will use a carefully designed experiment to change the number and functional traits of prairie plant species growing together and measure the effects of these changes on ecosystem functions. Those results will then be compared to patterns in real-world prairies to test their realism. Throughout the project, students, conservation practitioners, and members of the public will engage with the research process. A course-based undergraduate research experience will be created between the two partner universities; networking field trips for students from underrepresented groups will take place at both universities; and at least 9 students and early-career researchers will be trained. Ecologists’ efforts to understand the relationships between variation in biodiversity and ecosystem function have led to a consensus that the trait diversity of communities influences their function. Biodiversity change includes both changes in richness and community assembly – the non-random additions and subtractions of species from communities. The project will establish a biodiversity–ecosystem function experiment in which species richness, composition, and functional trait diversity are independently manipulated in plots. Species combinations will be parameterized using empirical field data from restored tallgrass prairies to ensure the experiment retains realism. Further, herbivory treatments will simulate bison grazing effects on prairie plants. In this way, the project will use experimental plots with realistic communities to determine how variation in the number of species and their assembly affect ecosystem functions, including above- and belowground biomass, leaf litter decomposition, and ammonium uptake. Community and ecosystem measurements in real-world prairie restorations with bison present will then be compared to results obtained from experimental plots to determine if experimental results can be used to predict dynamics at larger spatial scales. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.