Arid areas, which already comprise more than 40% of land on earth, are expanding in many places. Yearly differences in climate greatly affect the ecology and evolution of plants and animals in these drylands. The Sevilleta Long-Term Ecological Research (LTER) site in New Mexico includes five major dryland habitats or ecosystems. This research will expand ecological knowledge of those ecosystems. The guiding question is: How do long-term climate trends drive what happens in dryland ecosystems? In particular, how does one type of dryland ecosystem get turned into another type? Scientists will develop new theory to predict what happens when, for example, it rains less. They will collect the long-term data needed to test their ideas. They will also do experiments that change patterns of rainfall. This project will allow scientists to improve forecasts for drylands, transforming our understanding of these ecosystems worldwide. Scientists at Sevilleta will recruit and train a diverse workforce through activities at all levels of learning. These include many schoolyard lessons, undergraduate research programs, and interdisciplinary graduate and professional training. Societal impacts of the program include strong collaborations with local, regional, and national land managers.

The Sevilleta LTER program will test how changes in climate mean and variance independently and interactively affect the dynamics of dryland ecosystems and the transitions between ecosystems. Research activities will evaluate the generality of mechanisms that control sensitivities of dryland populations, communities and biome transitions to climate variability by integrating long-term observations and experiments with theoretical, statistical, and simulation models. Moreover, the diversity of Sevilleta ecosystems and ecotones will enable comparative study of the causes and consequences of dryland transitions and foster new cross-site collaborations. Three novel models will assimilate observational and experimental results to forecast effects of climate variability on (i) transitions driven by the spatio-temporal trajectories of foundation plant species, (ii) ecosystem functions and services in five widespread dryland ecosystems, and (iii) consumer dynamics via climate impacts on the distribution of resources.

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.