Ecosystems containing several species are more productive than individual species on their own. Using data from more than 400 published experiments, an international research team has found overwhelming evidence that biodiversity in the plant kingdom is very efficient in assimilating nutrients and solar energy, resulting in greater production of biomass.

"Plant communities are like a soccer team. To win championships, you need a star striker who can score goals, but you also need a cast of supporting players who can pass, defend and keep goal. Together, the star players and supporting cast make a highly efficient team," says Lars Gamfeldt of the Department of Marine Ecology at the University of Gothenburg.

Gamfeldt is part of an international research team led by Brad Cardinale (University of Michigan, USA) which, in a special issue of the scientific journal American Journal of Botany on biodiversity, presents a study on the significance of biodiversity of plants and algae, which form the base of the food chain. The research team based its study on the question whether ecosystems can maintain important functions such as production of biomass and conversion of nutrients when biodiversity is depleted and we lose species. In their quest for answers they have examined hundreds of published studies on everything from single-celled algae to trees. Using data from more than 400 published experiments, the researchers found overwhelming evidence that the net effect of having fewer species in an ecosystem is a reduced quantity of plant biomass.

There are two principal explanations for why species-rich plant communities may be more effective and productive. One is that they have a higher probability of including "super-species," that is to say species that are highly productive and effective in regulating ecological processes. The other is that different species often have characteristics that complement one another. The fact that there is a "division of labour" among different plant species in nature makes it possible for species-rich communities to be more productive. The researchers also note that as a result of climate change and other human impact we are now losing species at a rapid rate. This means that we need to prioritise what we want to protect and preserve, in order to maintain the goods and services humans depend on.

"Nearly every organism on this planet depends on plants for their survival. If species extinction compromises the processes by which plants grow, then it degrades one of the key features required to sustain life on Earth," the principal author of the article Brad Cardinale comments. Gamfeldt is affiliated with both the Department of Marine Ecology at the University of Gothenburg and the Department of Ecology at the Swedish University of Agricultural Sciences.