How important are rare species for ecosystems?

This research tackled the controversial question of whether the loss of rare species will damage the functioning of ecosystems, and to what extent more common species can buffer the impacts of extinctions. The study examined three highly diverse ecosystems: coral reef fish, alpine plant communities and tropical forest trees. It investigated whether rare species in each of these ecosystems carried out distinctive functions, or whether so-called ‘functional redundancy’ in other species would insure against loss of rarer plants and animals.

In the case of tropical forests, the study used records of 662 species available through GBIF in French Guiana, Suriname and Guyana, combined with field data collected by the research team from forest plots. It found that rare species were disproportionately responsible for vulnerable functions in the ecosystem: for example, the recently-described forest tree Pouteria maxima, which grows to more than 40 metres in height in French Guiana, has very thick bark and leaves that make it exceptionally resilient to fire and drought, and thus a potentially important buffer to maintain forest structures and functions during climate change.

The research came to similar conclusions in the coral reef and alpine plant ecosystems, where rare species were also associated with vulnerable functions. The authors say their findings highlight the need to change thinking about biodiversity in general, and conservation strategies in particular, by moving beyond focussing on iconic and charismatic species, and concentrating instead on protecting species that support irreplaceable ecosystem functions and associated services.