Researchers have found clear evidence that biological communities rich in species are substantially healthier and more productive than those depleted of species.
Using new scientific techniques, U.S. Geological Survey research ecologist Jim Grace and a group of international scientists have resolved a long-standing debate about whether species diversity is necessary for a healthy ecosystem.
Scientists have long hypothesized that biodiversity is of critical importance to the stability of natural ecosystems and their abilities to provide positive benefits such as oxygen production, soil genesis, and water detoxification to plant and animal communities, as well as to human society. In fact, because this assumption is intuitively true to the general public, many of the efforts of conservation agencies around the world are driven by the assumption that this hypothesis is scientifically proven. Although theoretical studies have supported this claim, scientists have struggled for the past half-century to clearly isolate such an effect in the real world. This new study does just that.
“This study shows that you cannot have sustainable, productive ecosystems without maintaining biodiversity in the landscape,” said Grace.
The scientists used data collected for this research by a global consortium, the Nutrient Network, from more than a thousand grassland plots spanning five continents. Using recent advances in analytical methods, the group was able to isolate the biodiversity effect from the effects of other processes, including processes that can reduce diversity., Using these data with “integrative modeling”–integrating the predictions from multiple theories into a single model—scientists detected the clear signals of numerous underlying mechanisms linking the health and productivity of ecosystems with species richness.
“The ability to explain the diversity in the number of species is tremendously important for potential conservation applications,” said Grace. “The new type of analysis we developed can predict how both specific management actions (such as reduction of plant material through mowing or increase in soil fertility through fertilization), as well as shifts in climate conditions, may alter both productivity and the number of species.”
According to Debra Willard, Coordinator for the USGS Climate Research & Development Program, “These results suggest that if climate change leads to reduced species or genetic diversity, which is a real possibility, that then could lead to a reduced capacity for ecosystems to respond to additional stresses.”
As an indication of the global awareness of this issue, the Intergovernmental Platform on Biodiversity and Ecosystem Services was recently created to help policy-makers understand and address problems stemming from the global loss of biodiversity and degradation of ecosystems.
The article, “Integrative modeling reveals mechanisms linking productivity and plant species richness,” is available online in the journal Nature.