ECOSYSTEM STABILITY AND BIFURCATION IN THE LIGHT OF ADAPTABILITY THEORY

In the author’s laboratory an experiment of the following type is performed. Replicas of “jar microecosystems” are prepared as identically as possible from undefined pond material (water, bottom matter). Ensembles of these replicas are then cultured in incubators under varying degrees of statistical uncertainty and physical stress. Such microecosystems, like all ecosystems, undergo a sequence of changes (called succession) until they reach a climax form of organization. This is a form of organization which appears to be stable in the sense that it persists for a relatively long time. A necessary condition for such persistence is that the system is somehow capable of either dissipating or absorbing without visible effect the perturbations to which it is being subjected; after all, if it were not capable of doing this it would continue to change. By choosing the degree of environmental uncertainty it is thus possible to prepare (through the culturing process) ecosystems capable of absorbing or dissipating at minimum this degree of environmental uncertainty. The ability to cope with (absorb or dissipate) environmental uncertainty will be called adaptability. Thus, the imposed uncertainty of the culturing environment provides an operational definition of minimum adaptability. Once systems with defined minimum adaptabilities are prepared, many questions might be asked. For example, does actual adaptability tend to decrease in the direction of the minimum possible? What is the relation between adaptability and the stability of succession? What is the relation to the spectrum of particular forms of adaptability (e.g., genetic, organismic, populational) and to patterns of community organization? The intention of this paper, however, is not to consider the experimental aspect of this problem, but rather to describe a formalism which makes it possible to approach complete, self-sustaining biological systems of the above type theoretically, in particular to analyze the complex of adaptabilities underlying their dynamics. The essence of this formalism (hierarchical adaptability theory) is an entropy theory analysis of the state-to-state behavior of ecosystems in which the state specifications are structured in a way which reflects the hierarchical and compartmental organization of complete, self-sustaining biological systems (including their environment). After briefly reviewing this formalism (cf. also Conrad’-’), we shall state and prove the bootstrap principle of hierarchical adaptability theory (that the assumption of structured descriptions is self-justifying). The bootstrap principle underlies the major conclusion, viz., that as the dynamics of any particular level in an ecosystem appears more autonomous (i.e., more amenable to 465