A major focus of macroecology is predicting patterns and changes in the abundance, distribution, and energetics of individuals and species in ecosystems from limited prior knowledge. The Maximum Entropy Theory of Ecology (METE), based on probability and information theory, allows inference of the functional forms and parameter values describing the central metrics of macroecology, including the species abundance distribution and the distribution of metabolic rates or body sizes across individuals. In METE, the maximum entropy inference procedure is implemented using the constraints imposed by a few macroscopic state variables, such as the number of species, total abundance, and total metabolic rate in a community. Although the predicted metrics adequately capture many pervasive empirical patterns in relatively static ecosystems, there is evidence that in ecosystems in which the state variables are changing rapidly, many of the predictions of METE systematically fail. Here we extend the static theory to achieve a dynamic theory (DynaMETE) of macroecology. We construct coupled differential equations for the rates of changes of the state variables and the time evolution of the metrics of macroecology that result from the specific mechanisms that disturb the ecosystem from steady state.
Results/Conclusions
As a first application, we apply DynaMETE to a forest ecosystem that has been partially isolated from its immigrant source pool. We show that the theory predicts a transition of the species abundance distribution (SAD) from the steady state log-series distribution toward a lognormal distribution with relatively fewer rare species, consistent with a dynamic process of competitive exclusion. DynaMETE also predicts patterns of increasing abundance and species richness on newly created land masses that differ in diagnostic ways depending on whether immigration or speciation is the primary driver of diversification. In contrast to a forest newly isolated from its source of immigrants and thus losing species, during diversification DynaMETE predicts rank-abundance plots with a downward concave shape, suggesting rapid radiation and/or colonization. DynaMETE describes observed departures of observations from static METE predictions in disturbed ecosystems, points to early warning indicators of disturbance, and can identify dominant mechanisms causing disturbance, without detailed information about functional groups, traits, or niches.