In a new paper led by Martin Trappe we present density functional theory for ecology (DFTe)—a new framework for ecological modelling. Ecology currently has detailed mechanistic theories that can describe the interaction of a few interacting species at small scales, and statistical theories that can describe the dynamics of large numbers of species at large scales. But a persistent challenge is to develop unified modelling approaches that can span a range of temporal and spatial scales.

In the new paper, we draw on density functional theory, which has found wide application to many-body problems in physics. We take density functional theory’s computational framework and apply it to ecology, demonstrating with several examples its potential power for predicting the outcome of ecological interactions. In essence, our DFTe takes data from simple systems (e.g., two-species competition), fits an energy functional to the data, and uses this to predict the outcomes of more complex systems (e.g., multi-species competition). The applications we present range from classic two-species algal competition experiments to microbial predator–prey systems to tropical forest tree communities. We believe that our DFTe can contribute to a more unified understanding of ecological systems.

Martin is a Senior Research Fellow in the Physics department; this project arose from his two-year 50% appointment in the Biological Sciences department a few years ago. The paper has just been published in Nature Communications.

Trappe, M.-I. and R. A. Chisholm. A density functional theory for ecology across scales. Nature Communications 14:1089

One of our case studies focussed on Tilman’s (1981, Ecology) classic algal experiments. Photos at top show some of the algal species concerned (photo credit: Jason Oyadomari for the first two images and Don Charles for the third). Graphs at bottom show predicted outcomes from a hypothetical experiment of four algal species competing for two resources (only results for three species are shown because the fourth always went extinct). Predicted algal abundances from our DFTe (vertical axes) were almost identical to those of Tilman’s R* theory (horizontal axes). Each point shows the results for one randomly chosen pair of values for the resource input rates (greener colours indicate points closer to the one-to-one line).