"The results of our study emphasize that we need to consider not just how productive ecosystems are but also how stable they are in the long-term, and how biodiversity is related to both aspects of ecosystem functioning," says Andy Hector.
The researchers also found that grassland diversity and stability are reduced when fertilizer is added. Fertilizers are intentionally used in grassland to increase livestock fodder. Fertilizer addition is also occurring unintentionally in many places around the world because nitrogen, a common fertilizer, is released into the atmosphere from farming, industry, and burning fossil fuels. Rainfall brings nitrogen out of the atmosphere and on to grasslands, changing the growth and types of plant species. This study placed measured amounts of fertilizer on a portion of their research sites and measured the changes that ensued.
"What we find is that the stabilizing effect [of species diversity] is lost, and we have less stable ecosystems when we have more nutrients coming into that system," says Borer. This, the researchers found, was due to more synchronized growth of plants, eliminating the "portfolio effect."
This study was made possible due to the formation of the Nutrient Network, also known as NutNet. Borer and Seabloom led a small group of scientists who created NutNet to standardize the way that ecology research is conducted. NutNet is a "grassroots campaign" that is supported by scientists who volunteer their time and resources. There are now 75 sites around the world that are run by more than 100 scientists participating in the NutNet experiment. "It's a great project and I'm happy to be a part of it," says Hautier. "The collaboration is fantastic."
NutNet scientists collected data for this study for three years, measuring plant growth in 41 sites on f
|Contact: Stephanie Xenos|
University of Minnesota