Hartvigsen, G., A. Kinzig, and G. Peterson. 1998. The use and analysis of complex adaptive systems in ecosystem science. Ecosystems
1: 427-430.

Ecological systems are complex assemblages of interacting organisms imbedded in an abiotic environment. Complexity arises from inter- and intra-specific interactions among individuals or agents, interactions across trophic levels, and the interactions of organisms with the abiotic environment over space and time. In addition, interactions can range from strong and direct to weak and diffuse and are modified by both positive and negative feedback with the environment. In our effort to understand pattern formation at the community or ecosystem level we are confronted with the daunting array of processes that function across different spatial and temporal scales. We are thus forced to address the question of how these different levels of organization can be integrated, or how mechanisms and patterns at one level of organization can be understood in terms of processes operating at a different level of organization.

The goal of this Ecosystems Special Feature is to provide an overview of the relatively new approach of analyzing ecosystems using complex adaptive systems (CAS) theory. Complex adaptive systems theory is an extension of traditional systems theory (e.g. von Bertalanffy 1968), but addresses one of the omissions of systems theory--namely, adaptation--by specifically modeling how individual variation and changes in that variation lead to system-level responses. To introduce this Special Feature we distinguish systems theory and complex adaptive systems theory, outline the articles in this Special Feature, and suggest new ecological insights that could emerge from CAS-based approaches.