CAREER: Untangling the effects of multiple environmental drivers on dryland plant communities to inform land management decisions

This project will test how fire, invasive species, and environmental change affect biodiversity in rangelands. Much of the western U.S. is home to big sagebrush. This ecosystem supports many wild species and livestock grazing.

However, big sagebrush communities are declining due to stress that causes loss of biodiversity. Because most ecosystems experience multiple stressors at once, it is important to learn how they work together to cause biodiversity loss. To study this, this project will test which combinations of threats are most likely to reduce the ability of these systems to recover and cause the loss of big sagebrush habitats.

The project will also investigate if there are ways to manage livestock grazing to help sustain native plant species. The results will inform grazing practices for the western U.S. where livestock production is a significant economic driver.

The overall objective is to understand the likelihood of dryland state transitions resulting from the combined effects of multiple environmental drivers and determine to what extent transitions can be prevented using strategic livestock grazing, such as targeted grazing on invasive species. The project will co-produce data products with land management partners for a range of projected futures across large spatial scales to inform decision-making amid nonstationary, novel conditions, and to enhance the ability of managers to solve complex global change challenges.

This project will integrate empirical data and simulation results from STEPWAT2, an individual-based plant model that explicitly represents fine-scale ecological and environmental processes relevant for drylands. Simulations will be used to test the individual and combined effects of these drivers under a comprehensive set of traditional and strategic grazing regimes to quantify the conditions where interacting environmental drivers are likely to lead to state transitions and whether strategic grazing can shift the competitive balance between native and invasive species and enhance ecological resilience.

The project will advance the field of ecology by providing new insights into the likelihood of state transitions, along with identifying how plant community responses diverge based on life history traits and resource availability.

This project is jointly funded by Population and Community Ecology and the Established Program to Stimulate Competitive Research (EPSCoR).

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.