Public and professional ideas about ecology often differ

Surveys have shown that many people think that there is a “balance of nature,” in which natural systems are stable and tend to return to an original, preferred state after a disturbance, and that each species in nature has a distinct role to play in maintaining that balance.

Public views on the balance of nature with stable, orderly systems were once held by many ecologists. However, ecologists now recognize (1) that natural systems do not necessarily return to their original state after a disturbance and (2) that random effects often play important roles in nature. For example, as we will see in Unit 5, current evidence suggests that different communities can form in the same area under similar environmental conditions. Therefore, unless they provide careful qualifications, few ecologists today speak of a balance of nature.

Some ecological concepts have remained unchanged through time. In particular, early ecologists and contemporary ecologists would agree that events in nature are interconnected (via the physical environment and via interactions among species). As a result, a change in one part of an ecological system can alter other parts of that system, including those that govern life-supporting processes such as the provision of food, clean water, and shelter from the environment.

Overall, although the natural world may not be as predictable or as tightly interconnected as early ecologists may have thought, species are linked to one another. For some people, the fact that events in nature are interconnected provides an ethical imperative to protect natural systems. A person who feels an ethical obligation to protect human life, for example, may also feel an ethical obligation to protect the natural systems on which human life depends.