If you’ve ever moved, you might remember mapping out new routes to work, the grocery store, and other key locations. Perhaps it took you a couple trips to get completely oriented.
You’re not alone. Many animals—including the bison recently reintroduced to Banff National Park—go through a similar process when adjusting to a new habitat.
Reintroduction programs are often touted as a way to mitigate biodiversity loss, but the prospect of large, highly mobile animals wandering outside park boundaries poses safety concerns for both humans and bison.
Reintroduction programs
Unintended dispersal (e.g., free-roaming bison) is one of the reasons that reintroduction programs are often unsuccessful, says Tana Verzuh, a PhD student in the UW Department of Zoology and Physiology and Program in Ecology and Evolution.
Verzuh studies animal spatial learning, the process by which animals learn and memorize their surroundings. Starting in 2020, she has worked with Parks Canada to evaluate the effectiveness of different management tools in helping reintroduced bison learn—and remember—the boundaries of their new home. “If we are seeking to alter an animal’s behavior, we need them to learn,” she says. “But with reintroduction, we also don’t want to overstress them because we want them to settle.”
In 2017, 16 bison from Elk Island National Park were transported to Banff National Park. The bison were contained in a large enclosed pasture for a year and a half, allowing them to gradually adjust to their new environment before they were released into the park’s full expanse—more than 2,500 square miles, 96 percent of which is considered wilderness.
The Parks Canada team monitored the herd and employed various management techniques to ensure the animals remained within the park’s boundaries. Meanwhile, Verzuh used GPS collars and remote sensing data to track each bison’s behavior as they explored their new home.
Hazing and stress
For researchers interested in understanding animal learning and memory, reintroduction programs present a unique opportunity. Reintroduction allows researchers to observe how animals move through and settle into a completely unfamiliar environment—and how management techniques affect this process.
The most successful management strategies use “hazing” methods that are stressful enough to be effective, but not so stressful that they discourage reintroduced animals from settling into their new environment, Verzuh notes.
In Banff National Park, the Parks Canada team used a variety of hazing strategies to prevent the bison from straying beyond the park’s boundaries. Hazing techniques were implemented on foot, on horseback, and via helicopter.
Verzuh’s team predicted that exposure to stronger negative stimuli, such as helicopters, would cause greater stress responses in the reintroduced bison than less invasive tactics, such as guiding the animals back into the park’s inner region on foot.
Their data supported this hypothesis. Specifically, they found that hazing on foot, hazing on horseback, or installing fencing in strategic locations was less effective at changing behavior than using helicopters or employing multiple forms of hazing in combination.
The researchers found that helicopter and combined hazing techniques increased the speed and duration of the bison’s movement, but the effects diminished after about 36 hours. “Bison are a social species, so blowing groups apart can be really stressful—but we found that wasn’t happening,” Verzuh explains. “We saw an increased stress response, but it wasn’t elevated or prolonged, and we didn’t see a really negative effect on group dynamics.”
That’s largely due to how Parks Canada team members used the hazing techniques, she says. They intentionally avoided pushing the animals too hard, taking care to never induce a full-out sprint.
When stressed, animals tend to select safe habitats, such as places that provide cover or familiar locations. However, even when helicopter hazing was employed, Verzuh didn’t observe significant changes in habitat selection, suggesting that the bison were stressed enough to avoid the hazing area but not so much that they were prevented from settling into their new environment.
Effective management
For a management program to be truly successful, reintroduced animals must learn to consistently avoid the areas where hazing occurred, not just flee in the moment.
The bison in Verzuh’s study continually returned to locations where they encountered low-stress management techniques, indicating a lack of associative learning. In contrast, they rarely, if ever, returned to locations where they experienced helicopter hazing or combined hazing.
Verzuh’s results suggested that higher-stress management techniques, when implemented thoughtfully, were most effective at promoting long-term associative learning. “This active management has really helped successful reintroduction,” she concludes. “They still explore once in a while, but they’ve settled on the landscape.”
Currently, more than half of reintroduction programs fail. But Verzuh is hopeful that using animal learning to inform management strategies will facilitate better outcomes. “If we evaluate different tools through the framework of animal learning, we can select more effective tools based on behavioral changes,” she says.
To learn more, contact faculty advisor Jerod Merkle at jmerkle@uwyo.edu.
This article was originally published in the 2024 issue of Reflections, the annual research magazine published by the UW College of Agriculture, Life Sciences and Natural Resources.
