Sustainable development: Lessons from the paradox of enrichment

With the current struggle to "sustainably" exploit our biosphere, the "paradox of enrichment" remains an issue that is just as relevant today as it was when it was first formalized by Rosenzweig in 1971. This paradox is relevant because it predicts that attempts to sustain a population by making its food supply more abundant (e.g., by nutrient enrichment) may actually have the reverse (paradoxical) effect of destabilizing the network. Originally, this paradox was based upon studies of "reasonable," but quite simple, predator-prey models. Here, we attempt a more "realistic" revision of the paradox that explicitly accounts for the embedded nature of the human system in a complexly interwoven set of hierarchical (spatial, temporal, and organizational) relations with the rest of the ecosphere-a relationship whose exploitative nature continues to grow in intensity and extent. This revision is attempted with the aid of a combined thermodynamic and network approach. The result is that a scale-dependent asymmetry in the action of the second law of thermodynamics is shown-an asymmetry that results in the creation of two antagonistic propensities: local order and local disorder. The point of balance between these two propensities is empirically measurable and represents a balance between processes and constraints internal (growth and development) and external (interactive and perturbing influences) to a system-a balance that may be called the most "adaptive" state (after Conrad 1983). The use of such an index of this balance is demonstrated and it is used to clarify the relevance of the paradox to more complexly organized systems. As a consequence, we conclude that the concept of "sustainable exploitation and growth" is an oxymoron.