The Trophic Structure of Ecosystems and Economies

By Johannes Alke

Supervisor: Dr. Susanne B. Unger

In ecology, the concept of Trophic Structure describes how the flow of energy and material through ecosystems gives them structure through the feeding relationships between species. It relies on the fact that in most ecosystems, only species capable of photosynthesis such as pants and algae can 'produce' their own energy from sunlight. Other species need to rely on either consuming plants, making them one step removed from primary producers, or consuming other animals, making them two or more steps removed. This categorizes them into layers. With each layer, most of the consumed energy is not available to the next because it is expended for survival. Through this, the population of species is increasingly restricted the more steps they are removed from plants.
In its earlier days, the theory of trophic structure benefited from an adaption of input-output analysis as used by economists, and in the last few years, a number of papers have attempted to apply trophic concepts to economics, with varying degrees of success and accuracy. The purpose of my Final Project was to compare ecosystem and economy at the level of individuals and systemic interaction to investigate whether there is a basis for speaking about a trophic structure of the economy, and how the the trophic structure of these different systems compares.

My findings are that there are parallels in the properties of individual units (species and companies) which in turn create some similarities in the shape of their systemic interactions. However there are also major differences. While in ecosystems, the main resources of energy and matter flow in the same direction, in the economy the resources of money and material, which companies require to compose their physical existence and pay for inputs, flow in opposite directions. Each resource flow has its own origin layer, respectively households who spend money and the companies which source material from the environment. The opposing flows are what permits mutually beneficial exchange between companies, whereas feeding relations in the trophic model of ecosystems are usually one-sided and negative for the one being fed on. This is not universal however, as there are cases of symbiosis, for example when energy is being exchanged for something less tangible such as protection (ants herding aphids) or insurance against individual misfortune (mycelium networks sharing around resources between trees). In a similar manner, the economy also has occasional predatory relationships, wherein one company uses a position of power to overtake or drive out another, thereby facilitating its own growth.