Authors: Ichchha Thapa*, Indiana State University, James H. Speer, Indiana State University, Andria E. Dawson, Mount Royal University
Topics: Biogeography, Paleoenvironmental Change
Keywords: Greater Yellowstone Ecosystem, Bayesian, Forest Dynamics, Disturbances
Session Type: Virtual Paper
Start / End Time: 8:00 AM / 9:15 AM
Room: Virtual 30
Presentation File: No File Uploaded
Forest ecosystems cover almost one-third of the global land surface and are under mortality stress caused by climate change and land-use change. There has been growing evidence of widespread and rapid forest decline and mortality as a result of increasing temperatures, drought events, and other related stressors. These stressors are further exacerbated by the interaction of multiple disturbances such as fire and insect outbreaks, resulting in dieback and potential regime shifts. The forests of the Greater Yellowstone Ecosystem are not an exception to these stress-induced changes. In this study, we used a network of ring-width chronologies from a variety of sites in the Greater Yellowstone Ecosystem and reconstructed disturbance events. We developed a Bayesian hierarchical model and attempted to understand the tree growth response to climate variables, fire, and insect outbreak events and to quantify their differential effects on forest dynamics. Preliminary results indicated that the disturbances are affecting forests at the species and stand level. Higher elevation forests are moving upslope along the elevational gradient. Temperature stress has been found to impact mature trees by switching from a minimum temperature response to a drought response. Mountain pine beetle outbreak documented around 2010 killed many of the whitebark pine trees resulting in gaps in the canopy. Understanding how these stressors interact with each other and the complex mechanisms driving forest ecosystems helps to predict future scenarios and be prepared with adaptive forest management interventions.