Whole ecosystem manipulation experiments: The search for generality

The objective of this paper is to summarize population and community level responses observed during two recent whole-ecosystem manipulations, and then to examine those results in light of the literature. The paper addresses the question: 'Are there generalities in the ways that structure and/or function respond to experimentally imposed stresses? ' It was found that the effects of any disturbance first occur as changes in the function (physiology) of individual organisms. Depending on the characteristics of the disturbance, and the system, effects may later become manifested at higher levels of biological organization. The integrative nature of structure and function at the community and/or ecosystem level precludes the use of either class of variable alone for reliably assessing responses to disturbance. Additional aspects of the subject are discussed.