Century-old ranchland study yields new data on climate change, evolution of North Dakota's native prairie
When researchers at the Northern Great Plains Research Lab near Mandan first began researching the sustainability of North Dakota’s native grasslands in 1916, the words "climate change" would have meant little to them. But a century-old study is aiding new research to address today's problems.
MANDAN, N.D. — When a small team of scientists began researching the sustainability of North Dakota’s native grasslands on a few hundred acres of prairie just west of the Missouri River in 1915, the words “climate change” would have meant little to them.
Rather, researchers at the Northern Great Plains Research Laboratory were looking to answer a question of practical significance to North Dakota’s growing population of homesteading ranchers: How many acres of the state’s native grasslands are needed to sustain a single steer?
More than 100 years later, a version of that grazing experiment, initiated by an agronomist named Johnson Thatcher Sarvis, continues at the lab’s field site south of Mandan, an outpost of the U.S. Department of Agriculture. The lab notes that it is one of the longest-running experiments in North America.
Today, its results also inform questions that may never have occurred to Sarvis and his colleagues during their lifetimes.
“The physical experiment continues, but the data and availability of that data allows it to be used for new and creative uses,” said Mark Liebig, a USDA soil scientist, one morning last year at the site of the historical pastures of Sarvis’ evolving experiment.
Among those new uses is research into two trends of increasing consequence to North Dakota farmers and ranchers: the state’s steadily warming climate and the gradual displacement of many of the native species that once populated its grasslands.
Today, on the close to 50 acres of prairie where Sarvis began his grazing study, federal scientists have adapted the original experiment to investigate questions like the capacity of North Dakota’s grasslands to absorb climate-warming greenhouse gases. The undisturbed historical pastures have also allowed researchers to track an invasion of plant varieties that have taken over North Dakota’s prairie, weeding out much of its species diversity.
Such long-term experiments have become a specialty of the scientists at the Mandan lab. It's an approach that has been important in a region of weather extremes where "it doesn’t mean anything to talk about averages," Liebig said. Dramatic swings between sweltering summers and subzero winters, between flood years and prolonged drought, call for extended treatments that capture the responses of the land to highs and lows.
Even as decades-old experiments at the Northern Great Plains Research Lab feed into new research on climate and vegetation change, scientists at the lab said their long-term research is laying groundwork to address tomorrow’s problems, too.
“In 20 years, we don't know what the questions are going to be,” said John Hendrickson, a USDA rangeland scientist and one of the stewards of the Northern Great Plains Lab’s historical pastures.
But decades down the road, Liebig said, “if you still have the treatment, if you still have the samples, they still might be able to tell a story.”
Climate change and the native prairie
Already, the Upper Midwest’s changing climate has spurred measurable effects for North Dakota agriculture.
State climatologist Adnan Akyuz, of North Dakota State University, said average temperatures in North Dakota have risen by about 2.4 degrees Fahrenheit over the last hundred years. That trend helped the state’s growing season expand by more than three weeks since the late 1800s.
Among other ripple effects, Akyuz noted the surge of North Dakota’s corn and soybean crops, which historically were confined to states farther south.
At the Northern Great Plains lab, the historical pastures where Sarvis began his study have become a rich site for research into the effects of these warming trends for both agriculture and the local ecology.
In addition to the research underway by USDA scientists like Liebig and Hendrickson, the land of Sarvis’ original study now serves as an observation point for a sweeping climatological study by the National Ecological Observatory Network, or NEON, a long-term experiment funded by the National Science Foundation.
With stations at more than 100 locations around the country, the recently launched NEON project is collecting a wide range of climate and ecological data. Its observatory tower on the Northern Great Plains lab's historical pastures, a kind of souped-up weather station, is a few years into a process of collecting localized climate readings, as well as helping measure factors like moisture, salt concentrations and carbon dioxide levels in the prairie soil.
Andrea Anteau, a field operations manager for NEON in North Dakota, said the project intends to measure how those variables change over a 30-year span and provide the findings as a “data utility” for anyone who wants them. She said NEON selected the Mandan lab as a host site in part for the insights offered by the century’s worth of data and samples available there.
“We're here to collect data for the next 30 years, but we also need to understand the context for what happens,” she said. “The Mandan research site has a tremendous amount of scientific context.”
Among the well-established environmental shifts observed on the historic pastures is one mysterious phenomenon of concern to local ecologists: a dramatic change in the species diversity of the North Dakota grasslands.
In a building at the Northern Great Plains lab, Hendrickson spread out a collection of hand-drawn maps that date back to the start of Sarvis’ experiment. They depict in meticulous detail nearly twenty species in just one square meter of the historic pastures.
Tracing the maps, Hendrickson said many of those species are either gone or greatly diminished, replaced largely by the invasive Kentucky Bluegrass. The early 19th century drawings depict an abundance of grass varieties like blue grama and needle-and-thread, and almost no Kentucky Bluegrass.
When Hendrickson and others surveyed the pastures in 2017, Kentucky Bluegrass accounted for 80% of the species composition while blue grama had been reduced to just 1%. Needle-and-thread was not found at all.
What precisely is responsible for this displacement continues to evade scientists, Hendrickson said. But thanks to the continuation of Sarvis’ study, researchers were able to see that it happened rapidly, mostly between 1980 and 2000, when the composition of Kentucky Bluegrass eclipsed all of the other species combined.
Even so, other research by Liebig, Hendrickson and their colleagues at the USDA lab has found that North Dakota’s native grasslands, even under this species shift, offer potentially impressive benefits to today's climate challenges.
Taking readings on the same historical acreage where Sarvis began his study, they have determined that, through moderate or heavy cattle grazing practices, North Dakota's native prairie can serve as a strong sponge for carbon dioxide and other greenhouse gases.
“There are so many different knobs and dials” that can shift the balance of greenhouse gases on agricultural land, Liebig said. Unlike land tested with a variety of crop rotations, the native grasslands have a distinct ability to absorb and trap carbon dioxide and potent greenhouse gases like methane and nitrous oxide.
In other words, putting a large ruminant on North Dakota’s prairie and letting it eat can actually act as a viable strategy for mitigating climate change.
“That’s pretty powerful, I think,” Liebig said of the findings. “It really does say something about the value of our native lands.”
A scientific tradition
When Liebig and Hendrickson each came to the Northern Great Plains Research Lab in the late 1990s, they joined the field station's long lineage of government scientists. The USDA outpost, which today belongs to a national network of 18 federal sites dedicated to long-term agricultural research , was first established under an authorization of Congress in 1912 and has since been home to dozens of scientists and hundreds of staffers and seasonal workers.
Since the early days, researchers at the Mandan lab looked for sustainable ways to work the land in North Dakota while also chronicling the effects of less environmentally friendly practices.
“Nature rebels at abuse of pasture,” read one 1937 Bismarck Tribune headline hailing findings from the lab: “Sarvis reveals that man’s greed and lack of knowledge ruined range.”
More than a century since Sarvis began, scientists at the Northern Great Plains Research Lab have looked to sustain a legacy of long-term research — a practice Hendrickson said is dwindling in agricultural spheres today, even as an appreciation for its value has grown.
Long-term research is a major investment, Liebig noted. It requires patience, decades of commitment, continuous access to land and the scrupulous keeping of methodology and data as experiments are handed off from one scientist to the next.
Of the lab’s research into changes in local grassland species, Hendrickson said, “I still find it really incredible that someone said, ‘let’s look at the grazing study that they did.’ And then someone said, ‘let’s keep it going.’” Some 70 years on, a dramatic shift occurred on the North Dakota prairie, one that scientists would know less about if Sarvis’ experiment had been allowed to lapse.
“That’s incredible foresight,” Hendrickson said.
Liebig noted that "data becomes more valuable over time," and it’s the many workers of the “in-between time” at the USDA field station that have kept the records and allowed for the modern applications of old experiments.
“They don’t get any credit,” the soil scientist said. “We kind of pay our debts by investing in continuing these kinds of things, because we’ve benefited from the commitment of others who’ve come before us.”
Readers can reach Forum reporter Adam Willis, a Report for America corps member, at firstname.lastname@example.org .