The features of ecosystem structures are describable with the attributes "static", "fixed", "dynamic", "flexible" and "responsive" (cf. chapter 2). An ecosystem is relatively static because aggregate entities, which form the background for the ecological play, are more or less fixed (in terms of immobile). Furthermore, compound entities are liable to chemical and physical laws which usually do not change. The ecosystem's attributes "dynamic", "flexible" and "responsive" are based on the behaviour of the organic entities within the system. To specify the emphasis of the features, it is necessary consider the ecosystems environment with respect to their hierarchies and boundaries. Lunear periodics for instance are influencing the earth as a whole as well as various ecosystems since billions of years. Therefore, the tides are a stable phenomenon which not even humans can change. But humans as the "dominating organic entities" on the planet are able to modify trophic structures, destroy horizontal and vertical structures (e.g. from forests) and consequently change ecosystem functions. Homer-Dixon [2006, p. 232] describes the results of human acting within the context of the adaptive cycle (Holling cycle): "This is a moment of great volatility and instability in the world system. We need urgently to do what we can t avoid deep collapse. We also need to figure out how to exploit the opportunity provided by crisis and collapse when they occur, because some kind of systematic breakdown is now almost certain." A breakdown, or collapse would be fatal for humankind but at least the ecosystem structures will recover: "A collapse also liberates the ecosystem's enormous potential for creativity and allows for novel and unpredictable recombination of its elements. It's as if somebody threw the forest's remaining plants, animals, nutrients, energy flows and genetic information into a gigantic mixing bowl and stirred [...]. This is a perfect setting for the forest's plants and animals to experiment with new behaviours and relationships - a pollinator species like a bee or wasp will try gathering nectar from a type of flower it hadn't previously visited" [Homer-Dixon, 2006, p. 228]. The adaptive cycle which embraces two opposites (growth and stability on one hand, change and variety on the other) is hence reflected in the features of ecosystem structures. From the human point of view it is left to hope that we are responsive and flexible enough to maintain the present ecosystem structures as well as their functions.
References
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