Approximately 1% of all tree species are responsible for half of the carbon storage and productivity of the Amazon rainforest, reports a study published in Nature Communications. This emphasis on relatively few individual tree species, within the world's biggest tropical forest, raises concerns regarding the resilience of these species to climate change.
The Amazon rainforest is an extremely important carbon sink, accounting for 17% of the carbon stocks contained within global terrestrial vegetation. It is also the largest and most diverse tropical forest in the world, hosting an estimated 16,000 different tree species. Despite this huge diversity, a relatively small minority of species are extremely common, with half of all Amazonian trees accounted for by as few as 227 hyperdominant species. The effect that this phenomenon of hyperdominance has on the Amazon's carbon storage remains unknown.
Sophie Fauset and colleagues analyse a unique dataset of 530 forest plots, containing information on species abundance, tree diameter, wood density and biomass for more than 200,000 individual trees from 3,458 species. Through the statistical analysis of these data, the authors reveal that of the estimated 16,000 species within the Amazon, biomass and productivity are concentrated into as few as 147 and 167 individual tree species, respectively, and that these species are generally characterised by large size.
While the authors' findings indicate that a small fraction of Amazon tree species contribute disproportionately to carbon storage and cycling, this does not necessarily indicate that high diversity levels are irrelevant for the long-term survival and health of tropical forests.