Exploring interactions among multiple disturbance agents in forest landscapes: Simulating effects of fire, beetles, and disease under climate change

Global climate varies naturally at millennial time scales, but humans, primarily through combustion of fossil fuels, have now added sufficient greenhouse gases to the atmosphere to cause rapid climate warming at a rate unprecedented in the last 10,000 years (IPCC 2007). In light of its potential adverse effects on natural, political, social, and economic systems, ecologists have been called upon to investigate the consequences of anthropogenic climate change on the world’s ecosystems (Bachelet et al. 2001; Schneider et al. 2007). However, questions pertaining to the numerous, complex, and multi-scale interactions among ecological processes, disturbance agents, and climate drivers present intractable challenges with respect to scientific exploration, as traditional field methods used to explore ecosystem responses to environmental change are inadequate to capture complex interactions that occur across large areas and long time periods (Fig. 8.1). Multi-scale ecological interactions often result in nonlinear feedbacks that produce novel and unanticipated landscape responses to changing climates (Lauenroth et al. 1993; Temperli et al. 2013). These can be explored using simulation modeling, in which computer programs are developed to quantitatively simulate complex ecological processes and their interactions over decades or centuries (McKenzie et al. 2014).