Bison: The Latest in Carbon Capture Tech
Author: Pam Wright | Date Published: December 20, 2017
To hear Mimi Hillenbrand tell it, American bison are more than just the majestic creatures that once graced the grasslands of the Northern Great Plains by the millions until we nearly wiped them off the face of the earth. They may very well play a role in saving us from ourselves.
“They’ve have been around for millions of years …” Hillenbrand says. “They are just so American, so us.”
Hillenbrand owns and manages 777 Bison Ranch in Hermosa, a 26,000-acre ranch that has been the site of the several movie productions, including “Dancing With Wolves” and “Wyatt Earp.”
The ranch has been in her family since the 1970s, when it was still a cattle ranch. The land, at the time, was in bad shape and overgrazed, she told weather.com.
For a time, the family grazed both cattle and bison, but a particularly brutal blizzard in the 1980s prompted her family to make the switch completely to bison and to employ different grazing methods that has made a difference in the health of the land. They now grass-feed just under 2,000 bison.
“The switch fits our goals of trying to bring back native grasses and trying to leave the land in a better state for the next generation,” she said.
One of the added benefits of making the switch, she said, is what she learns from the massive animals that at one time numbered upward of 60 million in North America but have now dwindled to some 400,000.
“They teach me something every day,” she said, adding that she admires the animals named America’s national mammal by Congress last year because “they are still wild, they are intelligent and curious, and they know the land and the weather,” perhaps even better by instinct than humans.
They may also have a role in healing the land and reducing global warming.
Vulnerability to Global Warming
The Northern Great Plains are particularly vulnerable to the effects of human-induced climate change, according to the congressionally mandated 2017 United States Climate Assessment Report.
Some of the greatest increases in average temperatures in the U.S. are expected in the region over the coming decades. A projected increase of 4.05 degrees Fahrenheit in average temperature is expected by 2065, and a projected increase of 9.37 degrees Fahrenheit in average temperature can be expected by the turn of the century if nothing is done to curb emissions.
Hillenbrand, who has a bachelor’s degree in wildlife biology from the University of Montana and a master’s in agricultural sciences from Colorado State University, says her family already has noticed a difference since they purchased the ranch more than 40 years ago.
“Definitely the weather patterns are changing here,” Hillenbrand said. “We used to have some wind, but now the winds are horrible. Winters are drier and temperatures in the spring are in the 90s when they shouldn’t be.”
The average annual temperature in South Dakota has increased by about 2 degrees Fahrenheit since the beginning of the 20th century, and most of that warming has occurred in winter and spring, according to weather.com meteorologist Chris Dolce.
“All but two of South Dakota’s top 10 warmest years on record have occurred since 1980, and four of the top 10 warmest years have been registered since 2005,” Dolce said.
The massive head of an American bison is captured on the 777 Bison Ranch during a snowstorm. (Toby Brousseau/777 Bison Ranch)
South Dakota’s annual average temperature is expected to increase to levels never before experienced in historical records by the end of this century, he noted.
“In summer, the number of 100-degree days in the northern Plains could double by the middle portion of this century,” he said.
Along with increased temperatures, the amount of precipitation observed annually is expected to rise in South Dakota, with the biggest upswing in winter and spring. Average precipitation could jump by 10 to 20 percent above current levels during the winter in South Dakota.
“Droughts will continue to affect South Dakota even as precipitation increases overall on an annual basis,” Dolce said. “In fact, the severity of droughts will rise in a warmer world due to an escalation in soil moisture loss from higher temperatures during periods of dry weather.”
A study led by Joseph Craine, former research assistant professor in the division of biology at Kansas State University, found that large livestock like bison will shrink over the next 50 yearswith rising temperatures, possibly causing billions of dollars of loss in the beef industry.
Craine and his team studied over 22 bison herds across the country and found that on average a 7-year-old male bison in Oklahoma weighed 1,300 pounds while an average 7-year-old male bison in the colder state of South Dakota weighed 1,900 pounds.
“We found that the warmer the climate that the bison are in, the smaller they are,” Craine told weather.com.
Craine noted that the difference in temperature between the two regions is about 20 degrees Fahrenheit and said while temperatures are not expected to rise that much due to global warming, ranchers can expect their yield to decrease as temperatures rise, which could translate into billions of dollars lost.
Another negative outcome of rising temperatures is a decrease in the amount of protein in the grass, which leads to a significant decrease in the size of America’s largest grazing animal.
Unfortunately, while the increase in carbon dioxide in the atmosphere might encourage plant growth, the resulting grasses would be poorer in nutrients, including protein.
“The trade off with better management of grasslands is more quantity, but the quality goes down,” Craine said. “When you talk to ranchers, they don’t really care about quantity, they care about quality.”
Making the Switch to Holistic Management
For the past 30 years, 777 Bison Ranch has employed grazing methods that Hillenbrand says is helping save the native grasslands, replace lost topsoil and aid in the fight against global warming.
Holistic management is the term now used for a philosophy previously known as the Savory System, named for Allan Savory, a Zimbabwean ecologist, livestock farmer, environmentalist, and president and co-founder of the Savory Institute.
Savory advocates using grazing methods that he says “mimics nature.” He believes the methods have the ability to heal the environment, and insists grasslands have the potential to sequester enough atmospheric carbon dioxide to reverse climate change.
In a peer-reviewed report included in case studies posted to the Savory Institute’s website, the authors note that before human intervention, large herds of bison and other large grass-eating herbivores migrated across millions of miles of grassland unencumbered by fences and development.
“In the past, large herds of herbivores moved over the grasslands in search of fresh grass and avoiding predators,” Daniela Ibarra-Howell, CEO and co-founder of the Savory Institute, told weather.com. “These herds grazed, defecated, stomped and salivated as they moved onto fresh areas, and would not return to those areas until they were fully recovered.
Holistic management is a method that tries to return the land and grazing animals to the way Mother Nature intended, a philosophy that many ranchers around the globe say is working.
“When I heard Allan speak in the ‘80s, I thought this just makes so much sense,” Hillenbrand said. “It just fit our goals and our vision, so we took the bit and ran.”
Hillenbrand says it’s a form of management that’s based on decision-making, setting goals and making decisions based on those goals. She and her three-person team carry out that vision by monitoring the grass, planning the grazing and moving animals.
Conventional rotational grazing practices move animals to different pastures at different times, sometimes coinciding with the seasons. The animals can remain for months on end in the same pasture, which can leave behind overgrazed and sometimes barren land.
Those who employ holistic management move the herds much quicker through smaller pastures — 777 uses 35 pastures — to allow the grass sufficient time to rest, recover and regenerate before the animals return.
The moves depend on many conditions, including the weather, and don’t necessarily follow a set rotational pattern.
“I generally plan between 45 days and 120 days of recovery time through a pasture,” Hillenbrand said. “Sometimes they are only in a pasture for half a day and sometimes it’s for two weeks.”
Hillenbrand points out that there are some ranches that do use traditional rotational grazing effectively.
The result of the lengthy planning process and sometimes challenging work, according to Hillenbrand, is a marked increase in topsoil, healthier grass and most importantly, no more barren land, which does nothing to absorb atmospheric CO2.
Holistic management also addresses a hot topic these days: methane, a contributor to global warming, released into the atmosphere by livestock.
Ibarra-Howell notes that naturally grazing animals and the flatulence and manure produced are not the problem. Human activity, such as feeding livestock unnatural foods and antibiotics to fatten them before slaughter, is the real problem.
Studies have, in fact, linked antibiotics in cattle to increased methane emissions from cow dung.
Unhealthy livestock management “creates all kinds of unintended consequences, such as turning the asset of manure into a liability,” she said.
“By properly managing domestic livestock on grasslands, healthy ecosystem function can be restored with soils rich with microbial life, including methanothrophic bacteria,” she said.
While there have been no testing to determine how much methane is being released from the 777 Bison Ranch, Hillenbrand says she has 30 years of monitoring the results, 30 years of data and 30 years of monitoring the grass to validate the philosophy as a whole.
“In those 30 years, we have built topsoil, our diversity has increased. We have healthy animals and we have healthy plants,” she said. “It’s amazing what happens using bison as a tool to fertilize with their dung and urine. Their hooves break up the soil that needs to be broken up and they put down litter that covers bare soil, and with climate change, as you know, bare soil is the worst thing ever.”
Hillenbrand is quick to point out, however, that holistic management is more than just how and when you move the animals.
“It’s encompassing the whole … the type of life you want to live, your vision for the land and your personal vision. You base your decisions on that.”
Carbon Sequestration: Grasslands as a ‘Carbon Sink’
It is believed that at one point, grasslands covered more than half the globe. In North America, a fifth of the continent was covered in grassland, but today, only 3 percent of tallgrass prairie remains, according to a Yale University study.
One of the touted benefits of holistic management and healthier grasslands is an increase in carbon sequestration, a fancy term that simply means using plants to absorb atmospheric CO2 through the process of photosynthesis, which pulls carbon and stores it in the soil.
Anything that absorbs more carbon than it emits is known as a “carbon sink.”
“The more plant material you have and the more live plants you have, the more carbon you are going to be sequestering into the ground,” Hillenbrand said.
Craine, while not necessarily an advocate for holistic management, agrees with Hillenbrand and others that plants may become one of the planet’s saviors, thanks to their ability to absorb atmospheric carbon.
“We need to get carbon out of the atmosphere … and we’re going to have to rely on plants to suck up the carbon,” he said. “The oceans are going to suck up a whole bunch, but as they do that, they acidify, and we don’t want that to happen. So ultimately, it’s going to be up to plants.”
To be effective, it will take a global response to take land that is now used for one purpose and change it for a different purpose, such as reforesting lands, Craig said.
Richard Birdsey, senior scientist of the Woods Hole Research Institute, told weather.com that the effectiveness of plants to sequester carbon varies by location and activity.
He notes that tools like COMET-Farm, a farm and ranch greenhouse gas and carbon accounting system, are available to estimate the amount of sequestration occuring by location and practice.
Another way to reduce CO2, Craine noted, is to use geological sequestration, which captures and locks CO2 deep in the ground using mechanical methods, a new and not yet perfected technique.
Last year, a team from the Wisconsin-based Applied Ecological Services conducted testing to see how much carbon 777 Bison Ranch was sequestering, along with the plant diversity and water infiltration as compared with other ranches in the area that use traditional grazing methods.
“We had twice as many native species in our grass than our neighbors,” Hillenbrand said. “We created inches of topsoil and when you think how long it takes to build topsoil and we did it in 30 years, it’s kinda cool.”
She noted that the study found that the ranch’s water infiltration was superior and the dung beetle population, a sign of healthy soil, was expansive.
“They found 10 different species of dung beetle,” she said. “Everything, our plants our root systems, is functioning really well.”
Steve Apfelbaum of Applied Ecological Systems told weather.com that 777 Bison Ranch has seen significant improvement.
He noted that in areas where there was intensive grazing over very short durations, followed by a long period of recovery, soil carbon, infiltration rates and protective plant cover increased.
“Some of the highest increases are being measured in the locations with cattle stocking rates that are very high compared to the normal stocking rates used by most ranchers,” he said.
He added that the greatest difference occurs “where ranchers are going well beyond the holistic management philosophy” by encouraging the “restoration of deep rooted native cool and warm season plant communities comprised of native plant species, not just any green plant that provides forage,” like alfalfa.
A healthy earth system relies on global methods that “emulate historic ecosystem functions — such as large herds of bison, caribou and wildebeest,” he said.
Large herds stimulate both vegetation above ground and to the roots below, which “appears to rapidly extract CO2 from the atmosphere.”
“This we have documented to date in some parts of the North American grassland ecosystems.”
Enough Evidence to Justify?
While there are ranchers around the world marveling at the success stories being shared about holistic management, researchers, scientists and academics are not so quick to agree.
Most say there is just not enough scientific evidence to confirm the results.
“Places that will talk about holistic management will say, we can take a degraded grassland, one that’s been overgrazed and use our special grazing approaches to lock up carbon in the soil,” Craine said. “That’s the hook that they’ve said for a long time. Whether that’s substantiated by scientific evidence, that, I would say, is an open question.”
Proponents of the philosophy say doubts stem from an unwillingness to change years of tradition and methods.
“You have to change a mindset and when you have people doing the same type of grazing for years, it’s hard to change their minds.” Hillenbrand said, noting, though, that the method is beginning to gain traction.
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