Climate change isn’t the only thing ecologists worry about when they consider how humans are impacting the natural world.

Two University of Minnesota professors say nitrogen and phosphorous from fertilizers and fossil fuels are entering different areas of the ecosystem at such high rates that there needs to be ways to properly monitor the effects.

So they’ve developed the Nutrient Network, a global cooperative of scientists who have set up simple research sites that monitor how human-introduced nutrients are affecting grasslands.

“It’s one of the things that’s changed the world probably the most that we don’t talk about much,” said University Institute on the Environment Director Jonathan Foley. “We have significant pollution from excess nutrients, specifically things like nitrogen and phosphorous, in the environment.”

He said it’s common to see pollution near agricultural land because fertilizers taint water runoff. But nitrogen pollution also comes from the atmosphere when fossil fuels are burned, and nitrogen eventually finds its way into the ground and into new areas, he said.

“We, as ecologists, have told the story of carbon dioxide and the relationship between that and the climate and your car reasonably well,” said associate ecology professor and Nutrient Network co-founder Elizabeth Borer.

But what ecologists haven’t communicated well, she said, is how nitrogen from burning fossil fuels finds its way into grasslands. Once introduced into the atmosphere, the nitrogen comes back down as rain, she said, and that can find its way into some of those areas that previously weren’t receiving that much nitrogen.

Ecologists are uncertain how exactly this affects the ecosystem, but Borer said the Nutrient Network will help illuminate that.

Network studies published in the renowned journal “Nature” this January and February have shown that excess nutrients increase plant growth and production, acting as a fertilizer, but at the cost of diversity.

“As you fertilize systems, they get more productive, but also you get fewer species,” said Eric Seabloom, associate ecology professor and network co-founder.

While certain plants do much better because of this, he said, the grasslands are overall less stable and therefore less likely to prosper over time. Displacing natural grazers from the land and overusing livestock also play a major factor in the diversity of grasslands, he said.

For now, the Nutrient Network spans 78 sites in 17 different countries, but Seabloom and Borer said they think it will continue to grow. They recently added more sites in Germany and Australia, and they hold an annual convention to help spread awareness and increase
recruitment.

Senior lecturer Jennifer Firn at Queensland University of Technology in Australia said she joined the Nutrient Network in 2008 because she thought it could help her answer questions about the prevalence of invasive species in grasslands. Joining the network is voluntary, so Firn spent about $500 to set up her three sites, but she said it was well worth it.

The network has not only provided a great source of global data, she said, but it has acted as a forum for support and ideas.

“If you’re working on a paper, you have just a ton of people to help out with the statistics, with the writing, with the conceptual framework,” she said. “Everyone brainstorms. If you were to do that on your own, you would never create the same kind of product.”

Borer said to become a part of the network, researchers only need to learn the framework of their methods and have enough funds to set up their own site. The network received only about $400,000 in federal grant money to set up the entire project, she said.

Foley said that’s one of the main differences between this network and other similarly established networks like the National Ecological Observatory Network, which required hundreds of millions of dollars in infrastructural development and resides only within the United States.

“What they’ve done here is, with very little funding, been able to get scientists all around the world to coordinate their work and to speak about not just how one site is changing, but how the whole planet is changing,” he said.