An informational synthesis of ecosystem structure and function

The mechanistic view of ecosystem dynamics, being inherently reversible, seems ill-suited to describe directional behavior, such as ecosystem succession. A more conservative approach, such as one that involves probabilities, seems warranted. Work involving conditional probabilities has led to the development of a systems property called the ascendency, the increase of which appears to incorporate many of the changes that characterize the successional process. Ascendency originally was formulated entirely in terms of systems transactions. Hence, it did not address the crux of system dynamics, which is the connection between the stocks of taxa and the trophic flows between these populations. One may, however, expand the definition of system ascendency in a perfectly natural and consistent way to include compartmental biomasses. The principle of increasing ascendency, recast in terms of the new definition, provides a whole-system context for hitherto unexplained elements of traditional ecology. For example, the allometric trend during succession towards larger organisms with slower turnover times and the time-honored ‘Liebigʹs law of the minimum’ both can be derived from the revised principle. Furthermore, the same derivational techniques provide us with an entirely new criterion for identifying the limiting nutrient linkages within an ecosystem. Such a theoretical ‘prediction’ might augur the beginnings of a robust theoretical systems ecology