A major goal of metabolic ecology is to make predictions across scales such that individual metabolic rates might be used to predict the metabolic rates of populations and communities, but the success of these predictions is unclear given the rarity of tests.
Given that older communities tend to have species with slower life histories and larger body sizes, we hypothesized that the metabolism of whole communities should scale allometrically with their mass across successional stages.
We created experimental chronosequences of sessile marine invertebrate communities in the field. We then (1) determined the metabolic scaling of these whole communities across successional stages of different mass and (2) tested whether the sum of individual metabolic rates for the dominant species could predict overall community metabolism.
Contrary to what we expected based on metabolic theory and succession theory, community metabolism scaled isometrically with mass across succession, despite the mean body size of dominant individuals within the communities increasing over time. We resolved this paradox by estimating community metabolism based on individual metabolic rates for the dominant species in the community. We show that non-random changes in the membership of the species maintain mass-specific metabolic rates of the whole community invariant across succession despite changes in size structure.
These results suggest that simple assumptions about how community-level processes scale up from species are unlikely to be correct, because community turnover is non-random with respect to metabolic rate. Nevertheless, with the appropriate parametrization, the sum of individual species rates can predict the function of the community as a whole. A plain language summary is available for this article.
- community ecology
- geometric biology
- trophic interactions