Regime Shifts in Social-Ecological Systems

What are regime shifts? Ecosystems consist of components that interact and self-organize through internal feedback mechanisms that maintain the system’s structure and function. Regime shifts occur when systems experience changes in their internal dynamics that push the system into a new state. 1,2 For instance, natural periodic fires help to keep grasslands structure; if fire is suppressed grasslands may shift to encroached shrubland. 3 In humid forests tree evapotranspiration is an important source of humidity for forest persistence. The loss of large tracts of forest may lead to declines in evapotranspiration, which will affect regional rainfall and cause further tree loss, pushing the system into a drier condition. 4 How do regime shifts occur? Regime shifts occur by means of two main mechanisms that can work together: 2,4 cumulative changes in ecosystem properties (e.g., vegetation cover, concentration of pollutants) that lead to a gradual loss of resilience and an intense shock (e.g., hurricane, oil spill) that drastically changes the system state. Resilience is the capacity of a system to absorb changes and disturbances and self-organize to keep the same structure and function.3, 5 As systems lose resilience they also become more vulnerable to changes (figure 1), hence, less disturbance is needed to push the system into a new regime. Figure 1. a) Mechanisms driving regime shifts can be depicted using “stability landscapes” 4, 11: valleys ...
Source: ActionBioscience - Category: Biology Authors: Source Type: news