Rangeland research targets grazing patterns

Cody Ward puts a University of Idaho GPS collar on a cow at his ranch south of Malta, Idaho, in this April 2018 photo. Researchers are using tracking technology and rangeland observations to calibrate satellite imagery of grazing.

Pairing satellite imagery with technology to track cattle movement on the range and field estimates of forage could give ranchers and land managers a new tool in grazing management.

That’s the goal of researchers at the University of Idaho College of Natural Resources who just won a $661,118 matching grant for the project from USDA Natural Resources Conservation Service.

The three-year project, Deploying CERT (Climate Engine Rangeland Tool), will kick off in January, Jason Karl, associate professor at the college and project leader, said.

The project will track cattle and measure forage on large rangeland landscapes and calibrate that information with satellite imagery in the CERT system — being developed by University of Idaho associate professors Crystal Kolden with the College of Natural Resources and John Abatzoglou with the Department of Geography.

The research team will outfit 300 to 400 cows with GPS collars developed by Karl and deploy them on the university’s Rock Creek Ranch, private ranches and Bureau of Land Management land in southern Idaho and on the Zumwalt Prairie Preserve in northeast Oregon.

“The whole idea is to see how we can do a better job at getting more timely information on how much forage is available and how much is being consumed,” Karl said.

Currently, only rough estimates or field observations are available to inform grazing-management decisions. The challenge on large landscapes is observing conditions across the expanse, which can lead to inaccurate estimates of available forage, he said.

The GPS data will be used to more effectively link on-the-ground observations of forage utilization with remote sensing techniques for mapping forage availability and change developed by Vincent Jason, a doctoral candidate at the university.

The resulting maps and forage utilization data will be built into CERT, an online tool to analyze and visualize information on how much forage the cattle consume.

Satellite imagery allows for monitoring landscape changes over time but it doesn’t provide information on what caused the change. The research will use the field measurements to inform the satellite imagery and give it greater content, he said.

“The (GPS) collars are the links that tie these two data sets together,” he said.

The collars will give on-the-ground verification where forage is being consumed by livestock, he said.

Ranchers and land managers will be able to access maps of forage availability through CERT, look at how the range and forage availability are changing over the growing season and decide when it’s time to move cattle, he said.

In some cases researchers will be able to distinguish livestock utilization from forage changes due to other events — such as insects and fires, which have distinctive patterns. The challenging types of events to distinguish solely from satellite imagery are forage utilization from wild horses or wildlife, he said.

“This is why the field observations will always be a necessary part of a system like CERT (and) rancher input is central to the CERT project. Without those field observations, the satellite forage maps have limited utility,” he said.

The long-term goal of the research, once the system is developed and demonstrated, is to expand it and deploy it in other areas, Karl said.

Matching funding for the project will come from the University of Idaho, The Nature Conservancy and the Idaho Department of Fish and Game.

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