Dynamics of social-ecological systems in the Colorado Front Range: Fire regimes, thresholds, and stable states

Forecasting change in mountain social-ecological systems presents significant challenges, as they are likely to display non-linear responses, i.e., they are more easily pushed or “tipped” across critical thresholds.  To investigate the behavior of high-elevation ecosystems in response to climate and human-induced changes and associated changes in ecosystem services, we have developed observational, experimental, and synthesis initiatives that integrate complex information at the scales of Colorado Front Range social-ecological systems. First, we have implemented a conceptual framework for social-ecological research for the Colorado Front Range that was formulated to explicitly integrate socio-economic and ecological disciplines via a series of broad questions.  

Second, we are investigating the circumstances under which crossing a single threshold between alternative regimes often leads to a “cascading effect” in which multiple thresholds across scales of space, time, and social organization, and across ecological, social, and economic domains may be breached. Third, the impact of such changes on ecosystem structure and function – including the creation of new stable states and or novel ecosystems – extends to ecosystem services, their interactions, and trade-offs.  We analyze the interactions between ecosystem services as a result of management for each of several individual ecosystem services. For example, as climate regulation has increased as a function of increasingly closed and dense forests, the capacity of landscapes to mitigate the size and intensity of disturbances has decreased. Trade-offs in ecosystem services, then, occur across space and time with different degrees of reversibility. But more than that, they often result in multiple ecosystem services being compromised for the benefit of a solitary ecosystem enhancement. We also analyze the relative change in ecosystem services since European settlement. Recreation value, for example, has increased at the expense of both water availability and natural hazard mitigation.