A new study, conducted by scientists at the Brown University, has shown that more plant diversity notably enhances an ecosystem's productivity.
The scientists, who conducted the first experiment in a natural environment, say that their finding highlight the significance of biodiversity to an ecosystem's value, such as capturing the global warming gas carbon dioxide.
Researchers including Osvaldo Sala, director of the Environmental Change Initiative said that the results confirmed tests showing the way biodiversity affects aboveground plant productivity in artificial ecosystems.
Aboveground plant productivity (ANPP) is the amount of biomass, or organic material, produced by plant growth.
However, the researchers found that the link between plant species richness, i.e. the number of plant species in a unit of area, and ANPP in a natural ecosystem was much higher than imagined. This implies that the greater the number of plant species, the more productive the ecosystem.
On the other hand, species loss has a particularly negative impact on ecosystems. This holds true for the role ecosystems play in capturing the global warming gas carbon dioxide. As the fewer the plant species in a given natural environment, the less carbon dioxide they capture.
"It's a double whammy. We not only are disturbing our planet by putting more carbon into the atmosphere, but we're reducing the ability of ecosystems to capture and store it," Sala explained.
They conducted their experiments in the Patagonian steppe, semiarid grassland located on the east side of the Andes Mountains in Argentina. They marked 90 plots, each containing three species of native grasses and three species of native shrubs. Later, they removed some of the species from the plots and measured each revised plot's productivity.
"The water is the same, the nitrogen is the same, the sunlight is the same. What is different is the diversity of the plants," said Sala.
In their experiments that started 2002, the researchers also learned that plant productivity in a flourishing ecosystem is enhanced because each species assumes a specific niche, called "niche complementarity."
The plants use the resources available to the whole system cordially, such as extending their roots at different depths in the soil, using different forms of nitrogen, and staggering when they photosynthesize.
"We are deeper into understanding the mechanisms of an ecosystem's productivity," said Sala.
The study is published in the Proceedings of the National Academy of Sciences.