Portions of the western United States are experiencing one of the worst droughts in a century, but little is known about how such climate change affects biodiversity (the number of species and their abundance), extinction, interactions among species, and the genetic basis of these interactions, all of which ultimately determine the health of these ecosystems. The investigators' 21-years of observations and experiments with pinyon pine span the wettest and driest periods of recorded history, allowing them to address these critical issues. During a long-term wet period, the PIs quantified how environmental stress and the genetic attributes of pinyon pine trees affected ~400 species of fungi and insects. Now, after 7 years of drought, they will revisit earlier study sites to: (1) determine how drought-induced changes in biodiversity affect the ability of pinyon pine to re-establish in areas where most trees have succumbed to drought; (2) determine if drought stress has resulted in increased numbers of herbivorous insects that attack drought-sensitive trees, which in turn alters the rest of the community; (3) determine if drought has reduced beneficial soil fungi that are necessary for tree survival and that allow the associated community to recover from drought; and (4) test whether tree rings can be used to predict how future climatic conditions will affect biodiversity. Because pinyon is a widespread conifer of the third most widespread vegetation type in the U.S., results from this work is likely to to apply to other areas of the U.S. Also, given that the frequency and severity of drought is predicted to increase in many areas of the world, and that the fungi and insects that form the focus of our biodiversity studies are important components of ecosystems world-wide, this research may help to predict changes in other systems. The research program includes training of graduate and undergraduate students, including Native Americans and Hispanics, and provides outreach to land managers and the local community interested in the impacts of drought on ecosystems.
