Trade-offs between competing functions prevent any one organism from excelling in all environments, promoting diversity in natural communities. In the Sonoran Desert, a trade-off between growth rate and drought tolerance contributes to coexistence among winter annual plants. The goal of this project is to determine whether this trade-off observed across disparate species reflects a deeper constraint operating within all species. Researchers will compare populations from across an aridity gradient in a greenhouse manipulation of water availability and use controlled breeding to estimate genetic constraints on growth and drought tolerance. A trade-off between growth and drought tolerance within species would indicate that fundamental constraints limit plant productivity and stress tolerance. If the trade-off is not apparent within species, then ecological processes such as competition create the key trade-off that structures the community.
This project will reveal potential constraints on population and community responses to climate change. The conceptual framework can also be extended to investigate why some non-native species become invaders that threaten biodiversity while others do not. The project will contribute to NSF goals for fostering education and diversity by supporting the research program of an early-career woman and providing training and mentorship for undergraduates from underrepresented groups.
