Editor's Choice June

The first paper by Christoph Mensen and colleagues “Stressor-induced biodiversity gradients: revisiting biodiversity–ecosystem functioning relationships”, uses biodiversity gradients to test to which degree a realistic loss of species due anthropogenic stressors impact the functioning of an ecosystem. Biodiversity-ecosystem functioning relations have to date mainly been analyzed in communities where species were randomly removed. In nature however, species loss is not random, but according to their sensitivity to environmental stress. In order to understand to which degree such a realistic species loss affects ecosystem functioning, the authors exposed marine benthic diatom communities to a series of treatments with the herbicide atrazine, one of the most commonly used herbicides worldwide. Because the species that contributed most to the ecosystem functioning were most sensitive to the stressor, they disproportionally impacted functioning of the mud system. This experiment demonstrates thus that our inference of BDEF must take-into account the natural sequences of species loss in order to predict the impact of diversity loss on the functioning of natural ecosystems.

The second EC by Giovanni Strona and colleagues reports on the underrated importance of predation in transmission ecology of direct lifecycle parasites. Predation is the primary route for transmission in parasites having complex life cycles. Using a large dataset of fish trophic interactions, the authors challenge the view that the transmission of parasites that use a single host (i.e., monogenean parasites) to develop and reproduce should is not affected by host trophic ecology. By means of network analyses, the demonstrate that predators and prey often share more monogenean parasite genera than explained by host habitat ecology, geographical distribution and phylogeny. Because a significant proportion of the studied prey-predator pairs showed a high parasite overlap at the species level, typical monogenean parasites are hypothesized to have evolved transmission strategies more targeted towards host interactions than towards species specific traits. If confirmed by other studies, this finding would imply that such specialised parasites would be much more vulnerable to co-extinction than previously thought.