THE DISTRIBUTION AND ABUNDANCE OF ORGANISMS AS A CONSEQUENCE OF ENERGY BALANCES ALONG MULTIPLE ENVIRONMENTAL GRADIENTS

We argue that observed patterns of distribution and abundance of plant and animal species within space and time are related directly to species-specific energy costs and gains (energy balance) in response to the many (Hutchinsonian N-dimensional) environmental or resource gradients. Competition, predation and other biotic interactions operate principally by increasing energy costs to the species, and can be included in our energy balance methodology as additional environmental gradients of energy costs. Persistence of a population and, ultimately, the species in a given locality, will occur only where energy return on investment allows a significant energy profit in the form of propagules. At any given time, energy investment in physiological, behavioral or morphological adaptations that optimize abundance at one point within the N-dimensional hyperspace of environmental gradients precludes the investment of the same energy elsewhere. Within the spatial and temporal range where the species can reproduce, abundance is related to the stochastic nature of important environmental interactions, because energy balance is ultimately controlled by the sum of organismal responses to all environmental influences. Populations tend to be most abundant where their genome allows the optimization of energy profits. Therefore, population dynamics reflect the cumulative effect of environmentally-induced shifts in organismal energy balance. If this energy balance approach is robust, it has the potential of synthesizing ecology at many levels.