Emergent properties

Emergent ecosystem properties are hierarchical characteristics of ecosystems which do not exist on the level of their subsystems. The properties emerge due to the interactions between the compartments. Emergent properties are not deducible if the subsystems are observed in isolation because their existence is dependent on hierarchical self-organized processes between the subsystems. Thus, emergent properties are holistic features of systems which are visible only if a synthetic approach is chosen. Reductionistic research strategies will not detect emergent properties. Emergent properties are discussed in this article from different viewpoints: After a general definition, the history of the concept of emergence is briefly described, leading to some basic statements about emergent features. As hierarchies can be taken as guiding principles, their role is exemplified on different biological and ecological levels-of-integration. From these examples, some prerequisites for emergence are discussed. Finally, a classification of emergent properties is proposed and a theoretical concept to quantify emergence is outlined.