Dimensionality of consumer search space drives trophic interaction strengths

TLDR: It is shown how substantial variation in consumption-rate data, and hence trophic interaction strengths, arises because consumers tend to encounter resources more frequently in three dimensions (3D) than two dimensions (2D) (for example, terrestrial and benthic zones).

Abstract: Interactions between the feeding habits of different organisms in a food chain or web trophic interactions can take place in two or three dimensions, and many communities show a mix of the two. By relating search rate and consumption rate to body mass, the authors show that the relationship between trophic-interaction strength and body size scales sublinearly in two-dimensional interactions but superlinearly in three-dimensional ones. They develop a model to show how this explains differences between, for example, aquatic and terrestrial ecosystems because the extra dimension provides an additional niche or opportunity in which to find resources. As an example, the model predicts that a foraging Galpagos sea lion could enjoy a consumption rate up to 30 times higher in a pelagic zone near the surface of the ocean (in three dimensions) than deep-down in a benthic zone (in two dimensions).