America’s native grasslands are disappearing
The Great Plains are being torn up at a ferocious rate – with frightening implications for biodiversity and carbon storage
When Patrick Lendrum steps out into a natural grassland, he gets an incredible feeling of vastness looking out over the land – no mountains or trees or forests, just open expanse.
“The solitude out there is incredible, and there’s enormous bird diversity in grasslands, the sounds that they make if you’re there in the spring,” says Ledlum, a scientist with the World Wildlife Fund’s northern Great Plains program. “It’s just this natural, incredible chorus and a lot of the species that you see on grass, and you don’t see anywhere else in the world.”
Grasslands used to cover a large swath of North America before European settlement. When Europeans arrived, they quickly plowed up about half of the grasslands on the continent and converted them to agricultural use, growing corn, soybeans and wheat. And today, new research shows the rate that the ecosystem is being lost has been increasing.
Lendrum led a research team that released a report in September showing that from 2018 to 2019 an estimated 2.6m acres of grassland were plowed up, primarily to make way for row crop agriculture – an area larger than Yellowstone national park.
For a few years, the rate of grassland loss was decreasing. But then in 2018 and 2019, the number started to increase again, Lendrum says. “That’s an alarming trend.” It’s also a huge blow for efforts to fight the climate crisis and represents a little reported unfolding environmental disaster in the US.
There are a web of reasons why more grasslands are turning into crops. Farmers and ranchers make decisions based on global commodity prices. There’s an increased demand for crops for human food, livestock feed and fuel. Biofuels like ethanol boomed in 2009 or 2010 and that increased demand.
“Grasslands are mostly used for grazing of livestock and when that balance gets out of line, and crop agriculture becomes more profitable, that’s when we see the resurgence of the tillup,” says Tyler Lark, an researcher at the University of Wisconsin who has studied grasslands for the past decade.
Urban sprawl also plays into it: Lark is researching the ways that croplands are being turned into housing – so the total amount of cropland isn’t expanding that much, but it’s being developed for residential use, and crops are being pushed to the periphery. “It’s almost a cascading effect, as we look at future urban expansion,” he says.
Lark’s research shows grasslands lost in the past years have been considered marginal, less productive land than other places where farmers could grow crops. At the same time, these marginal areas contain some of the highest-quality habitats – nesting sites for breeding birds and habitat for monarch butterflies.
There are enormous implications for climate change when people dig up grasses that have been intact for hundreds of years, because grasslands store tons of carbon in their soils. Native prairie grasses have deep roots that stabilize the soil and prevent erosion.
When people plow it up, it releases carbon into the atmosphere. It also exposes the soil to the air, which increases erosion and can also lead to nitrate leaching.
People often think of forests as natural ecosystems that store huge amounts of carbon, Lark says. But grasslands store immense amounts as well, out of sight, under the ground. “When we plow those up, a lot does become lost. If we can reduce the conversion, that will go a long way in lowering emissions.”
Once grasslands have been destroyed for agriculture, Lendrum says, it can take decades or even centuries to restore them. The WWF is working with landowners to convert croplands back into grasslands, but the process is slow and expensive. “Once that piece of grass is initially tilled, it’s very difficult to restore those ecosystem benefits,” says Lendrum. “Carbon in particular, it’s a slow process.”
Grasslands can seem like uncharismatic open land waiting for human activity. Everyone knows about the destruction of the Amazon, but grasslands are off their radar, in “flyover country”, Lendrum says.
Additionally, people need to eat, and there’s been a long history of moving west and growing crops in the prairies – American history is full of stories of expansion into the middle of the continent to farm food. And that need to generate crops has economic benefits but has to strike a balance with the ecological realities. Lark says the future is really about using the croplands we have already in the most efficient manner, and improving yields. “There is lots of room to expand production without expanding cropland area – it’s just easier to expand area than work on innovation.”
There is also an opportunity for leadership in the private sector and corporations, as consumers increasingly take notice. Just as increased attention to rainforests and savannah led to protecting them globally from deforestation, the same level of awareness could be applied to grasslands. Lark says he could see campaigns around native ecosystems, conversion-free supply chains, and products that aren’t contributing to the loss of grasslands.
Ben Turner, a natural resource management scientist at Texas A&M University in Kingsville, Texas, says he sees the seeds planted for a more active future: there is a renaissance of research in grasslands. And consumers are becoming increasingly interested in where their food comes from, how animals are cared for, and how the land is managed.
“We’re not going to reclaim even a small percentage of all the grasslands we’ve lost,” he says. But farmers can make cropland as functional as grasslands used to be, by diversifying crop systems, integrating livestock with crops, and finding ways to value ecosystem services like pollinators and migratory birds. “What needs to change is the public will to actually see changes happening – and that’s longer-term.”