Structure in ecology: a hierarchical concept of ecosystems

The place of life in our theories

This paper looks at the difficulty of finding a place for life in our theories of the world. Commonly in science one makes a distinction between appearance and reality, and science aims to find the reality underneath the appearances. However, as science currently understands reality, life is not a property of reality. Thus, either we have misunderstood reality, for living things appear to exist, or 'life' is not real, but simply a prejudice of unscientific common-sense. Neither option is easy to accept. The idea of emergence is investigated to see whether it can get us off the horns of this dilemma, but it is seen that it cannot, both theoretically, and practically, in the case of ecology. Finally it is noted that abandoning the appearance-reality distinction is a radical option which would mean a new conceptualization of science. The reasons for this are briefly indicated.

Organization of instabilities in multispecies systems, a test of hierarchy theory

The hierarchy theory predicts that system components functioning at lower levels of hierarchy operate or change at higher rates than the components at the level(s) above. If this prediction is correct, then interpretation of stability in complex ecological systems may be in need of revision. We test the prediction using a model of hierarchical structure of habitat and a coral reef fish community. We found that the variability of ecological range and abundance increases exponentially from habitat generalists (high in hierarchy) to specialists (low in hierarchy), as postulated by the hierarchy theory. Our result suggests that community stability is a composite property and should be evaluated by considering the hierarchical structure of that community.