Ecol. Lett. http://doi.org/hqw (2012)

Credit: © ISTOCKPHOTO/THINKSTOCK

Predicting the consequences of changes in biodiversity requires understanding of species' susceptibility to environmental drivers such as warming and their functional roles within ecosystems. Most studies so far have investigated the effects of random biodiversity losses. Although valuable, the limited realism of these studies limits their applicability to practical conservation problems.

Matthew Bracken from the Marine Science Center at Northeastern University, USA, and Natalie Low from the Department of Ecology and Evolutionary Biology at Brown University, USA, investigated the effect of realistic species loss on biodiversity by removing species from a rocky-shore community in a way that mimicked natural patterns of species loss.

Results indicate that the rarest species in this ecosystem act from the bottom up to disproportionately impact the diversity and abundance of consumers higher up the food chain. Losses of rare species — comprising <10% of biomass at the base of the food chain — resulted in a 42–47% decline in consumer biomass. These findings demonstrate the potential ecological importance of rare and otherwise seemingly insignificant species in determining ecological response following environmental changes.