Editor's choice December

EC papers for our last issue of 2015 are Mrowicki et al’s contribution on the context dependency of species loss effects in a marine system and Maino and Kearney’s synthesis on the variation in metabolic scaling in insects according to body size.

The impact of species loss on eventual ecosystem functioning is known to depend on the identity and sequence of removed species. Within this context-dependent framework, we might also expect these effects to be dependent on the local habitat, so when abiotic conditions change across space. By means of an elegant experiment using algae-consumer communities in two different types of intertidal habitat, the authors show that-despite some transient changes- effects of grazer loss on macroalgal cover, richness, evenness and assemblage structure were remarkably consistent across both habitats. In these intertidal systems, consumer diversity thus remains a primary driver of ecosystem functioning across widely different environmental contexts

Size dependency of metabolic rates is regarded as one of the most robust patterns (some use the word law) in ecology. Growth, maintenance and reproduction scale to body size. Thus, understanding constraints on the resource consumption rates of individuals should elucidate constraints on overall ecosystem functioning as well.  So far, we have a good understanding of individual species effects on the functioning of communities and some evidence is emerging on the role of individual variation and the resulting evolutionary dynamics. The importance of age and size structure for ecosystem functioning has to date only been rarely  studied, despite its importance for many population and community processes. Maino & Kearny advance the field substantially by combining simple modelling and meta-analysis to demonstrate that size variation by development differently scales to metabolism compared to size variation by ‘species’.  These results provide an explanation for the large variation in estimated metabolic scaling exponents and will definitively encourage future studies in metabolic ecology to make the important distinction between ontogenetic and evolutionary size changes.