Disking the River

How Platte River Management Makes Crane Migration Possible

Marissa Lindemann
December 13, 2023

Conservation groups will bring tractors like this one at Audubon’s Rowe Sanctuary to the Platte River to disk the sandbars in late August or September. Photo by Dakota Altman

The Platte River has become a jungle. It’s overtaken by the saplings that dig into the river, and the shrubs and weeds that crowd out any bare stretch of sand. A long row of circular blades pierces through the vegetation. The disks cleave the plants from their roots and churn them into the gritty sandbar on the central Platte River.

Invasive species like purple loosestrife and reed canary grass get churned into the soil in the disking process. Photo by Dakota Altman

Every September, conservation groups along the central Platte River, such as the Crane Trust, drag large agricultural equipment to the Platte River to disk the soil and rip out vegetation that’s taken root on the usual ever-shifting sandbars. This process is essential because migrating birds such as least terns, piping plovers, and whooping cranes prefer the open, bare sandbars to roost, nest, or watch for predators. Without river disking, trees would stabilize the sandbars of the Platte and disrupt the river’s flow while draining precious water from the river. Disking transforms the river from a jungle of invasive plants into an essential habitat for wildlife.

This timelapse from Audubon’s Rowe Sanctuary shows how disking transforms the central Platte River back into its original state with free-flowing sandbars

Disking is a Process

Brice Krohn, President and CEO of the Crane Trust, starts his day measuring the flow of the river. Anything faster than 1000 cubic feet per second, which would be the size equivalent of 1000 basketballs, means the Crane Trust habitat managers can’t disk that day without risking their safety.

After being hired by the Crane Trust in July 2023, Mallory Beckman took over disking responsibilities. For most of September, Beckman and another colleague, Gary Stizman, spent six to eight hours nearly every day in the tractor seat disking. Photo by Marissa Lindemann

Then comes the equipment: saws to remove the largest trees, and mowers with heavy-duty shredders to break up the vegetation. Currently, the Crane Trust has two John Deere tractors with rows of agricultural disks that work in tandem. Each blade is 18-30 inches long and can cut through some of the toughest invasive species that have overtaken the sandbars.

A row of large agricultural disks is pulled behind the tractors on the river so they can break up the root masses of invasive species and any plants that have overgrown the sandbars. Photo by Marissa Lindemann

Reed canary grass, cattails, purple loosestrife and phragmites are the primary offenders. Phragmites is a common invasive reed that grows rapidly by developing its network of roots horizontally instead of vertically. It can quickly take valuable space and nutrients from native plants and wildlife. Cottonwoods and cedar tree saplings, although native, are aggressive species with large root networks that require exorbitant amounts of water to sustain themselves. Without management, the woody species will suck the moisture out of the sand, which fixes the sandbars in place and chokes off the river water, fundamentally changing the structure of the Platte’s braided channels.

Phragmites is a fast-growing invasive plant believed to have been introduced from Europe in the early 1900s. Joshua Wiese, the range manager for the Crane Trust, says that the unique root structure is to blame for how quickly it has crowded out native species along the Platte River. Phragmite plants are connected with a horizontal root structure in which they can clone themselves very quickly and infiltrate new areas. Photos by Marissa Lindemann

The Platte River is a disturbance-dependent ecosystem. For many years, bison, fire, and floods ravaged the vegetation and kept the sandbars in constant motion. Now, because humans largely control the river’s flow, it’s up to the Crane Trust to mechanically simulate those naturally historic events.

“We try to replicate nature scouring by this heavy equipment going into the river,” Krohn said.

Conservation groups use a variety of equipment to disk the river, including saws, tractors, shredders, and articulated rotary cutters. Audobon’s Rowe Sanctuary manages about 3000 acres of habitat on or near the river, and they will disk every three years to remove vegetation. Photo by Dakota Altman

The river can be unpredictable, and even in shallow water, the tractors risk getting stuck in loose pockets of sand that act like sinkholes. Crane Trust employees can spend six to eight hours a day disking, and they must stay vigilant the whole time to not sink and avoid drop offs in the riverbed. If one tractor gets stuck, then the other will stop disking and return to pull it out. Disking is a time-consuming and oftentimes dangerous endeavor.

Conservationists have to be careful when disking so they don’t get trapped in loose sand pockets on the river. If they get stuck, one tractor will return and spend hours trying to pull out the other with a rope. Photo by Marissa Lindemann

“You might spend all day just getting unstuck from one 15 minute misjudgment,” Krohn said.

The Crane Trust is an educational habitat maintenance organization. Its mission is to protect the “Big Bend” area of the Platte River, about 80 miles between Overton and Chapman, Nebraska. They’ve been protecting crane habitat by disking for the past 45 years since the organization came to exist.

“We’ve been fine-tuning this mechanical treatment throughout that whole time frame,” Krohn said.

After disking, the Platte River returns to its natural state, one that resembles the way the river would look after floods. This bridge shows the boundary of the Crane Trust’s management area. The picture on the left shows the side of the river that hasn’t been disked, and the picture on the right shows the river after disking. Photo by Marissa Lindemann

From September 1 until the first freeze of the year, two Crane Trust employees will work together to clear as much vegetation from the riverbed as they can to make the habitat suitable for cranes. This year, they disked approximately 200 acres.

This year, the Crane Trust disked approximately 200 acres of the Platte River. Graphic by Sidney Parks

The Crane Trust isn’t the only organization that disks. Upstream, Audubon’s Rowe Sanctuary monitors around 3,000 acres of habitat. They disk on a three-year rotation and try to clear 100 acres yearly. This year, they disked approximately 250 acres.

Audubon’s Rowe Sanctuary disks the sandbars of central Platte River to remove vegetation and create suitable habitat for migrating cranes. Footage by Dakota Altman and Ethan Freese, Video by Marissa Lindemann

It Hasn’t Always Been Like This

The name of the Platte River is believed to be derived from the Jiwére (Otoe) word “Nebraskier” or the Umóⁿhoⁿ (Omaha) word “Nebrathka”, both meaning “flat water”. When French settlers reached the river, they began to call it “Nebraskier” from the Otoe word, and eventually, the French word “Platte” or flat was added.

 The Platte River is a braided river channel, which is a type of river characterized by having many temporary islands.

The river was described as a mile wide and an inch deep. Each spring, snow melt from the Rocky Mountains would push water and sediment downstream to form new sandbars, remove vegetation and reshape the landscape. Ice jams, which occur when ice chunks of frozen river water pile up around narrow points in the channel or obstructions, would block the river’s flow and cause seasonal flooding. As the river flooded the lowlands, ice jams would scour the river channel to remove vegetation. The seasonal flooding is an intrinsic part of the river system and creates the ever-shifting sandbars that give the river its unique morphology: braided channels.

Historically, ice chunks would dam up parts of the river in spring, causing the Platte to flood the lowlands. These ice jams would scour the river–  work that conservation groups now replicate by disking since the human management of the Platte has prevented its natural flooding patterns. Photos by Mariah Lundgren

The Platte River has always been a shallow river, but it hasn’t always relied on disking to prevent it from being overtaken by plants. Over the past century, humans have dammed, diverted and drained the Platte River, reducing it to a quarter of its historic flow. The Platte is used to irrigate millions of acres of farmland, generate millions of dollars of hydroelectric power, and provide millions of people with water. Approximately 70 percent of the river’s water has been removed or stored in reservoirs, causing the river to narrow. Vegetation continues to encroach the once-bare sandbars, exacerbating the problem by consuming more of the river’s water.

The Platte is a naturally shallow river characterized by its braided channels and many bare sandbars. Without conservationists disking, the river would narrow and lose its sandbars. Photo by Marissa Lindemann

Human control has so thoroughly inhibited the natural flow of the Platte, that seasonal flooding and ice jams cannot clear vegetation like they once did. Today, the Platte relies on humans to maintain its facade so it can be a home for many species, including sandhill and whooping cranes.

This is Critical Habitat for Cranes

The Platte River is a critical habitat for cranes, waterfowl, shorebirds, and other species. A few of these species, such as the piping plover and whooping cranes, are endangered, meaning they are at risk of extinction.

Whooping Cranes are endangered in both the United States and Canada, so it is rarer to find them on the sandbars. The white crane in this photo is a whooping crane and the gray cranes are sandhill cranes. Photo by Mariah Lundgren

Cranes in particular have an ancient history with braided rivers. Of the 15 crane species in the world, North America has the most populous: sandhill cranes, and the rarest: whooping cranes.

More than 1 million sandhill cranes and approximately 500 whooping cranes migrate through Nebraska every year. The sandhill crane spring migration begins in their wintering grounds in southeast Arizona, New Mexico, Texas and Mexico. On their journey north, they will stop in Nebraska during March to refuel for three to four weeks before continuing to their breeding grounds in Canada, Alaska, and Siberia. The Platte is a critical stopover point to rest and feed during this several-thousand-mile journey, especially for the whooping cranes, who are federally endangered in both the United States and Canada.

The whooping crane is one of the most endangered birds in the world. In the early 1900s, there were only 17-20 birds due to habitat loss and overhunting. Today, their population has grown to an estimated 540 birds, primarily due to work by private landowners, tribes, federal and state government agencies, and conservation groups like the Crane Trust.

Over 1 million sandhill cranes and approximately 500 whooping cranes will migrate through Nebraska in March on their way to their breeding grounds. The Platte River is a critical stop for them to rest and refuel before continuing their journey. Photo by Mariah Lundgren

“It just kind of brings it all together when you see this rare- the rarest- species of crane currently on your property and healthy because of the work you do,” Krohn said.

Crane migration has become an economic boon for Nebraska. Thousands of tourists, aka “Craniacs”, will travel to places like the Crane Trust to see cranes on their journey. A 2019 estimate said that 1.25 million sandhill cranes traveled through the central Platte.

The cranes used to be concentrated around Kearney, but as vegetation continues to overtake the Platte, the birds have started to move east in search for bare sandbars to roost. Sandhill and whooping cranes will only roost in areas without vegetation so they can watch for predators.

“The land that conservation groups own- that’s where the cranes are going,” said Joshua Wiese, a range manager for the Crane Trust.

Cranes will continue to return to the areas that conservation groups have disked because they feel safest on bare sandbars with high visibility so they can watch out for predators. Photo by Dakota Altman

Maintaining the Platte

For the past 45 years,  the Crane Trust has been adapting its land use management style to maintain the river and its inhabitants. Water use remains the biggest challenge, according to Crane Trust’s CEO Krohn.

“The key point is to keep the sandbars ever-moving and non-vegetated,” Krohn said.

In addition to disking, they’ll use prescribed fire to remove vegetation. They’ve found that cranes will often visit areas that have been recently burned because it makes it easier for them to bury their beaks in the ground to look for grubs.

Disking isn’t the only management practice used to clear the sandbars and protect crane habitat. The Crane Trust also uses controlled burns and grazing to control vegetation. Photos by Ethan Freese and Mike Forsberg

The Crane Trust has 173 bison in their conservation herd, which are sometimes used with cattle to graze the river banks like bison had historically.

Another conservation organization, the Platte River Recovery Implementation Program (PRIPP), removes vegetation by increasing the river’s flow every two to three years. They release “pulse flows” with water from an environmental account in Lake McConaughy, which is upstream on the North Platte. For three days in the spring, they release about 5000-8000 cubic feet of water a second to add sediment to the river and clear the sandbars.

Disking Opens Doors with Neighbors

Disking has extended benefits beyond habitat restoration. Krohn has found that it can improve relationships from across the river and create a commonality.

“It’s a great tool to open up conversation with neighbors,” Krohn said. Oftentimes, private landowners will ask the Crane Trust to disk their side of the river because they want the habitat to be suitable for cranes or to keep vegetation down for hunters.

Joshua Weise and Mallory Beckman both work for the Crane Trust to manage crane habitat. Like many conservationists, they know the importance of collaboration to protect endangered species like the whooping crane. Photo by Marissa Lindemann

Nebraska is 97 percent privately owned, so working with landowners is incredibly important for conservation groups to maintain the Platte River. Cody Wagner, the conservation program manager for Audubon’s Rowe Sanctuary, said that disking is an example of collaboration across public and private sectors.

“I think the cooperation that we see in the Platte River is sort of a shining example honestly, of how public and private partnerships can come together to accomplish greater goals than would otherwise be possible,” Wagner said.

The imprint of disking extends beyond the marks left on the Platte River’s sandbars; disking can also create community for people who live along the river. Photo by Dakota Altman

Wagner believes that there’s an underrated public benefit that comes with disking. Removing vegetation keeps the river bed wide, preventing major flooding and protecting homeowners from property damage. He argued it would reduce most of the need for disking if more of the water was naturally kept in the river. This saves the public money and protects valuable habitat, according to Wagner. The Platte River is part of Nebraska’s natural heritage, and it’s in Nebraskan’s best interest to conserve it.

“This is a unique landscape that we have right in our backyard and it’s important for us all to protect that, because it’s part of our story,” Wagner said.

The Platte River is part of Nebraska’s legacy and although it’s perilous and time-consuming, disking is necessary to preserve it as a unique habitat. Photo by Dakota Altman

My first time visiting the Platte River was during the process of creating this story. I had seen many pictures– Mike Forsberg originals– of the cranes and the riverbed. I had no idea what it would feel like until I stepped foot on the sandbars. My foot was immediately swallowed. I had expected a beach of hard-packed sand, but this was softer, kinetic. As I reached down to grab a fistful of the soft sandbar, it became obvious just how perilous disking is, how quickly a tractor could start to sink out here. Yet, they returned year after year spending monotonous hours in a tractor combing out weeds and sawing down trees. Why? It was bigger than themselves.

Humans had created this problem by draining and damming until invasive species and over-vegetation made this place inhospitable for wildlife that had no other place to go. So humans would solve it, too. Disking is necessary to sustain life on the Platte River until the disturbances we’ve tamed– fire, bison, and floods– can return to the ecosystem. There were 25,000 Cranes on the river when I visited, and they are there because of the work the Crane Trust and many other conservation groups do to preserve Nebraska’s legacy. You can do your part to preserve that Legacy, too. Advocate for cranes, and just keep disking.

Cranes are roosting on the central Platte River. Photo by Mike Forsberg

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PBT team photo. Summer 2023

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