Uncertainty, Complexity, and Ecological Integrity: Insights from an Ecosystem Approach

A new understanding of complex systems, and in particular ecosystems, is emerging (Kay, 1984, 1997; Holling, 1986; Kay et al., 1994, 1999). The hierarchical nature of these systems requires that they be studied from different types of perspectives and at different scales of examination. There is no correct perspective. Rather a diversity of perspectives is required for understanding. Ecosystems are self-organizing. This means that their dynamics are largely a function of positive and negative feedback loops. This precludes that linear causal mechanical explanations of ecosystem dynamics will suffice. In addition emergence and surprise are normal phenomena in systems dominated by feedback loops. Inherent uncertainty and limited predictability are inescapable consequences of these system phenomena. Such systems organize about attractors. Even when the environmental situation changes, the system’s feedback loops tend to maintain its current state. However, when ecosystem change does occur, it can be very rapid and even catastrophic. When precisely the change will occur, and what state the system will change to, are often not predictable. Often, in a given situation, there are several possible ecological states (attractors), that are equivalent. Which state the ecosystem currently occupies is a function of its history. There is not a “correct” preferred state for the ecosystem. This enhanced understanding of ecosystems, as complex systems, forms the backdrop for elaboration, in this paper, of the concept of ecological integrity.