RAPID: Historical contingency in ecology and restoration: environmental change, year effects, and priority effects in California grasslands

University Of California-Davis, Davis CA

Investigators

Abstract

This project explores how climate variation affects species in California grasslands. It builds on a long-term experiment in which different plants were planted in different plots, then monitored for many years. A four-year drought provided an unexpectedly strong test of how those plants respond to extreme stress. In the winter and spring of 2017, the drought suddenly ended; rainfall returned to normal levels. This dramatic change in conditions is a rare event and will likely have a strong influence on the types of plants that still live in the plots. Funding provided by this award will allow scientists to continue the experiment for at least another year to measure that influence. Understanding how cycles of rainfall influence plants is important for management of grasslands in light of possible long-term shifts in weather. This is a short-term continuation of a long-term project that, unfortunately, expired just as the drought was ending. The experiment extended by this award tests two opposing models of how natural communities develop after disturbance. One theory predicts that community composition will tend to return to the pre-disturbance state, regardless of the vagaries of early establishment. The other theory predicts that community composition is largely determined priority effects (i.e., the order in which species colonize after disturbance). The study will assess how an unexpectedly large disturbance in water availability affects the outcome of community assembly processes. In addition to providing training for students in research, the investigator will assist in local restoration projects.