Thursday, August 6, 2009: 8:00 AM-11:30 AM
San Miguel, Albuquerque Convention Center
Erica A.H. Smithwick, The Pennsylvania State University
Elizabeth Crisfield, The Pennsylvania State University
It has been several decades since the publication of several seminal papers in ecology that synthesized interactions between disturbances and biogeochemistry. The past 30 years has also been a period of intense change in human- nature interactions, in which humans have dramatically altered ecosystem health at multiple scales. Due to climate change and other direct human activities, the next 30 years are likely to bring increases in disturbance severity, extent, and frequency which are likely to result in feedbacks to global biogeochemistry. Understanding the context of these future changes has re-intensified scientific inquiry focused on understanding the resilience of ecosystems to perturbation.
In this session, we revisit ecological concepts developed over the past 3 decades focused on the interaction of disturbance, biogeochemistry, and resilience in terrestrial systems. We are interested in developing a framework to explain how shifts in system state can be explained in terms of disturbance and biogeochemical cycles (including both carbon and nutrients). We begin by proposing that this framework needs to incorporate spatial and temporal contingencies in a hierarchical framework. Then, we use empirical studies from multiple, forested-woodland systems to examine how ecological concepts of disturbance, biogeochemistry and/or resilience remain valid for specific systems, or need to be altered in this new context. Specifically, speakers will address the following questions, as appropriate: How do your research results fit into early and contemporary conceptual models of resilience, disturbance and/or biogeochemistry? Does system biogeochemistry in your location reflect disturbance-induced shifts in vegetation state and/or a direct response of disturbance events? Do disturbance modifications of biogeochemistry reflect a bottom-up control on ecosystem resilience? To what degree do your results reflect concepts of hierarchy & complexity (cross-scale interactions, thresholds, non-linearities) and spatial-temporal contingencies?
Our ultimate goal is to elucidate the consequences for altered disturbance regimes on terrestrial biogeochemistry. In this effort, we aim to contrast disturbance types and ecosystems in terms of the magnitude of modification of post-disturbance biogeochemistry and their potential for regime shift.