Paleoecology of Great Basin Pinyon-Juniper communities is being studied to provide sufficient information to determine ecological processes and relationships in Great Basin ecosystems.  Our mission is to investigate how those relationships will be affected by Global Climate Change, preidict site responses to management alternatives, and develop recommendations for maintaining site integrity.  The best source of information for understanding potential changes are the study if vegetation responses to past climate change.  Evidence from the past changes provide the data for testing predictive models of future climate change.  Arid and semi-arid Great Basin ecosystems are potentially some of the most fragile to global change.  Studies combining paleoecological records and current distribution of selected plant species permit estimation of their environmental limits.  Thus, the western Great Basin offers unique opportunities for these kinds of analyses.