Effect of consumer loss on resource removal depends on species-specific traits

Abstract

Negative effects of species loss on ecosystem functioning within and across trophic levels have been demonstrated across systems and organism groups. Recent meta-analyses showed that lower levels of consumer diversity lead to a reduction in resource removal. The strength of these effects seems to strongly depend on species identity, that is, species-specific traits, resulting in a variety of consumer interactions ranging from facilitating to strongly antagonistic effects. For a general test of trait-based effects of species loss, we conducted a meta-analysis on resource experiments including two consumer species. We calculated effect sizes of losing one of the two species, and related these to variables describing species' traits and experimental design. Our results show that loss of one species on average reduces resource removal supporting the hypothesis that loss of certain species-specific traits cannot fully be compensated for by biomass increases of the remaining consumer. However, the investigation of various consumer traits including body size did not allow for generalizations on the effect of loss of a certain consumer trait on resource removal.