OOS 27
Climate Warming, Changing Disturbance Regimes, and Forest Resilience

Wednesday, August 13, 2014: 1:30 PM-5:00 PM
203, Sacramento Convention Center
Jill F. Johnstone, University of Saskatchewan
Monica G. Turner, University of Wisconsin, Madison
Jill F. Johnstone, University of Saskatchewan
The frequency, severity, and extent of natural disturbances are changing profoundly as climate continues to warm, and these changes pose serious challenges to scientists, land managers, and society. How forest ecosystems will respond to novel disturbance regimes interacting with warmer climate is poorly understood but incredibly important to anticipate. Observations of past forest change and predictions from ecological theory suggest that, against a backdrop of changing environmental conditions, disturbances can trigger rapid change in forest ecosystems. Novel disturbance regimes may disrupt forest ecosystems and the processes that maintain them, and initiate new pathways of change by affecting post-disturbance community assembly and succession. Furthermore, changes to one disturbance regime may alter the likelihood or severity of another (i.e., linked disturbances) or produce compound disturbances that alter ecosystem resilience (i.e., the capacity of the system to recover following disturbance). The combination of changing climate conditions, altered disturbance regimes, and sensitivity of successional pathways to initial conditions creates a strong potential for rapid and non-linear shifts in forest ecosystem states. The aim of this session is to explore the mechanisms, dynamics, and implications of disturbance-mediated changes in forest resilience across different forest ecosystems. Presentations will tackle questions such as: What is the role of climate change in altering disturbance regimes and post-disturbance ecosystem recovery? How do disturbances interact across forest landscapes? What are the key thresholds, non-linearities, or leverage points in forest system dynamics? Under what conditions do disturbances trigger state changes in forest ecosystems? Examples will be drawn from a range of forests with an emphasis on northern and temperate forests of North America. We aim to identify commonalities that may lead to a more explicit framework for anticipating and managing forest state changes likely to occur with continued climate warming. The set of presentations will begin with an overview of disturbance dynamics and climate change, followed by presentations that address complementary topics that explore the nature of changing disturbance regimes, altered successional trajectories, and mechanisms that may underpin qualitative changes in forest landscapes. The session will conclude with perspectives on how our understanding of forest responses to changing disturbance regimes should influence our strategies of forest management. As the evidence for changing disturbance regimes accumulates around the globe, it is timely and important for us to consider how we can best anticipate the potentially dramatic impacts on forest ecosystems.
1:30 PM
 Climate change, disturbance regimes and feedbacks in an uncertain world
George L. W. Perry, University of Auckland; David Bowman, University of Tasmania
1:50 PM
 Testing theories of disturbance in temperate and boreal forests
Lee E. Frelich, University of Minnesota; Elias Anoszko, University of Minnesota; Roy L. Rich, University of Minnesota; Peter B. Reich, University of Minnesota
2:10 PM
 Linked and compound disturbances in subalpine forests: Bark beetles and fire
Tania Schoennagel, University of Colorado-Boulder; Sarah J. Hart, University of Colorado-Boulder; Teresa B. Chapman, University of Colorado-Boulder; Thomas T. Veblen, University of Colorado
2:30 PM
 Linked and compound disturbances: Forest disease and fire
Margaret R. Metz, University of California, Davis; J. Morgan Varner III, Mississippi State University; Kerri M. Frangioso, University of California, Davis; David M. Rizzo, University of California, Davis; Ross K. Meentemeyer, North Carolina State University
2:50 PM
 Landscape patterns and disturbance legacies: Is a warming climate altering spatial patterns of wildfire severity and post-fire forest succession?
Brian J. Harvey, University of Wisconsin; Daniel C. Donato, Washington State Department of Natural Resources; Monica G. Turner, University of Wisconsin, Madison
3:10 PM
3:20 PM
 Changing climate and novel fire regimes alter tree recruitment and postfire succession in northern conifer forests
Monica G. Turner, University of Wisconsin, Madison; Jill F. Johnstone, University of Saskatchewan
3:40 PM
 Triggers, thresholds, disturbance regime shifts, and state changes in forest ecosystems with climate warming
Craig D. Allen, Fort Collins Science Center, Jemez Mountains Field Station
4:20 PM
 Sensitivity and resilience of high-severity fire regimes to climatic variability from centuries to millennia
Philip E. Higuera, University of Idaho; Ryan Kelly, University of Illinois, Urbana-Champaign; Feng Sheng Hu, University of Illinois at Urbana-Champaign
4:40 PM
 Plant functional traits reinforce alternate successional trajectories in Alaskan boreal forest
Michelle C. Mack, University of Florida; Heather D. Alexander, University of Texas at Brownsville; April M. Melvin, University of Florida; Melanie Jean, University of Saskatchewan; Jill F. Johnstone, University of Saskatchewan