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Virginia Iglesias
Research Scientist
Earth Lab

Abstract

Socio-environmental dynamics are driven by top-down changes in climate and bottom-up positive (destabilizing) and negative (stabilizing) biophysical feedbacks involving disturbance and biotic interactions. When positive feedbacks prevail, the resulting self-propagating changes can potentially shift the system into a new state, even in the absence of climate change. Conversely, negative feedbacks help maintain a dynamic equilibrium that allows communities to recover their pre-disturbance characteristics. I draw on modern and paleoecological data and models to explore the relationship between socio-environmental resilience and altered disturbance regimes, and find that the ability of a social or natural system to recover its function after disturbance depends on the (i) intrinsic properties of the system, (ii) intensity of the disturbance, (iii) legacy of past events, and (iv) precariousness of the state variables or proximity to a bifurcation point.  This conditioning on system properties implies that, if resilience is a goal, disturbance events require an impact-oriented rather than a phenomenological definition (i.e., the concepts of largeand rareare site- and time-specific) and highlight the importance of the scale.  Scale-dependency, in turn, might lead to a divergence of the ecological and societal definition of sustainability, with large implications for management.