The Role of Mineral Weathering Rate Determinations in Generating Uncertainties in the Calculation of Critical Loads of Acidity and their Exceedance

Current legislation within Europe aimed at limitingecosystem damage resulting from inputs of atmosphericpollution is based on the critical load concept. Mineralweathering rates are central to the calculation ofcritical loads (acceptable levels) of acid deposition.The authors have undertaken a number of studies whichillustrate the complications and limitations inherent inpredicting mineral weathering rates and the implicationswhich these have for critical loads calculations andmapping. Calculated weathering rates and critical loadsfor two acid-sensitive parent materials (greywackes andgranites) are presented and are used to illustrate theimpact that uncertainty can have on critical loadexceedances. The results have obvious implications forportraying the uncertainties of critical loads to policy makers.     

Community-led reforestation: cultivating the potential of virtuous cycles to confer resilience in disaster disrupted social–ecological systems

Human relationships with trees can result in widespread citizen-led reforestation projects that catalyze social–biological-reinforcing feedback loops and set in motion virtuous cycles that restore perturbed social–ecological systems. These virtuous cycles confer resilience in such systems that counterbalance the tendency for vicious cycles to be triggered by destructive behavior and neglect. Given this argument, we ask: how do we cultivate the potential for virtuous cycles to confer resilience in social–ecological systems? To answer this question, we review feedback mechanisms and identify virtuous cycles catalyzed via ecological restoration to highlight their importance to the resilience of social–ecological systems. We then conceptualize these cycles with a causal map (also known as a causal loop diagram) illustrating an example where restoration activities and civic ecology practices contributed to feedbacks and virtuous cycles. Following from this example, we discuss approaches for recognizing and investing in virtuous cycles that accompany social–ecological systems and outline approaches for managing such cycles.