The parable of Green Mountain: Ascension Island, ecosystem construction and ecological fitting

Aims To use the ecosystem on Green Mountain, Ascension Island, to illustrate aspects of ecosystem construction and function as well as possible mitigation of human caused global environmental change. Location Ascension Island, tropical south Atlantic. Main conclusions The cloud forest on Green Mountain is a man-made system that has produced a tropical forest without any coevolution between its constituent species. This has implications for the way we think about ecosystems and provides a striking example of Janzen's idea of ‘ecological fitting’. This system provides ecosystem services, such as carbon sequestration, and illustrates the possible role of man-made ecosystems in the mitigation of global warming.