COS 89-6 - Quantifying the effect of disturbances on ecosystem services

Background/Question/Methods

Disturbances, such as storms, fires, droughts, and pest outbreaks, can cause major changes in ecosystem conditions and threaten the provision of ecosystem services. The intensity and frequency of disturbances are increasing under climate change yet most assessments of ecosystem services focus on average current conditions. In parallel, ecological studies often quantify community responses to disturbance, without considering ecosystem services. This focus misses potential impacts of disturbances on ecosystem services and their future stability. In response, we ask how disturbances can alter ecosystem services, addressing two questions: (1) How do disturbance regimes affect the levels and stability of ecosystem services?; and (2) Do changes in ecological communities and ecological community resistance predict such effects? We develop a general mathematical framework to quantify the impacts of disturbances on ecosystem services when disturbance occurrences and impacts are uncertain, and when disturbance regimes change under future climate scenarios. We demonstrate the application of this framework by quantifying consequences of extreme windstorms for ecosystem services in a mid-latitude forest in Northern Minnesota, USA.

Results/Conclusions

We find expected economic losses of 30% under current climate and 57% under future climate. Most approaches for assessing current or future ecosystem services would miss these losses by ignoring disturbances. Commonly used ecological measures of community resistance and stability also fall short, exhibiting low correlations or systematic biases when used to predict the windstorm impacts on forest services. Our results show that quantifying ecosystem services requires accounting for both disturbances and direct measures of ecosystem services and human well-being, particularly as disturbances intensify with climate change.