A new study led by the University of Washington has found that even in remote and rarely visited national parks, the presence of just a few humans impacts the activity of the wildlife that live there. The findings are published in people and nature.
People often visit US national parks to spot wildlife. But what impact does our presence have on the animals we hope to see?
Traffic in national parks has steadily increased over the past decade, and popular parks like Yosemite and Yellowstone can easily accommodate over a million visitors a year. In these high-traffic areas, one would expect animals to alter their behavior to avoid humans.
But a new study led by the University of Washington has found that even in remote and rarely visited national parks, the presence of just a few humans impacts the activity of the wildlife that live there. Almost any level of human activity in a protected area like a national park can alter the behavior of animals there, according to research published in the journal British Ecological Society people and nature.
It was eye-opening to see how many wildlife sightings we “miss”
“There is growing recognition of how the mere human presence in these places, and our recreation there, can impact wildlife,” said the lead author. Laura Prugh, associate professor at the UW School of Environmental and Forest Sciences. “These results are striking because they show that any level of human activity can have an effect on wildlife.”
The research team based their study in Glacier Bay National Park, a coastal area in southeast Alaska accessible only by boat or plane. Most visitors arrive on cruise ships, but the boats do not dock ashore and the park has very little foot traffic. Because so few people visit each year — only about 40,000 but growing — the park was an ideal place to locate this study, Prugh explained.
“Glacier Bay is a great park to explore what the lower limits are where humans start to affect wildlife behavior,” Prugh said.
Researchers worked with national park staff to design and implement an experiment comparing wildlife activity in areas frequently used by humans to areas where people were absent. They installed 40 motion-activated cameras at 10 sites to capture detections of people and four animal species – wolves, black bears, brown bears and moose – over two summers. By monitoring where and when people could access certain areas of Glacier Bay, then measuring wildlife responses to varying levels of human activity, the researchers identified two important thresholds.
So many people visit national parks for the chance to see wildlife, and that desire alone can reduce the chances of that happening.
First, if humans were present in an area, the cameras detected less than five animals per week for the four species studied. In most cases, this probably meant that animals avoided areas where humans were present. Second, in backcountry regions, wildlife detections dropped to zero each week once outdoor recreation levels reached the equivalent of about 40 visitors per week.
The researchers were surprised by the wildlife’s apparent low tolerance for the presence of people nearby.
“It was eye-opening to see the number of wildlife sightings that we ‘miss’ just by recreating in the Glacier Bay backcountry,” said the lead author. Mira Sytsma, who completed this work as a UW graduate student. “I was surprised to find that for all four species, wildlife detections were always highest when there was no human activity. So many people visit national parks for the chance to see wildlife, and that desire alone can reduce the chances of that happening.
Although all four species showed some change in activity due to humans, wolves were more likely to disappear from cameras when people were around. Brown bears were the least affected by human presence. Moose, however, were more active at times of day and in places where people were seen. Researchers hypothesize that moose may be using humans as a protective shield against predators, choosing to align their activity hours with humans to avoid becoming prey.
Researchers expect that in parks where the animals are more used to seeing people, at least some individual animals won’t react as strongly to humans as they did in Glacier Bay. But the findings highlight a reality likely playing out in national parks and wilderness areas across the country: More people are visiting these areas than ever before, and human presence is almost certainly impacting the behavior of animals that live there.
“I expect similar results can be found in other national parks, especially those with relatively low attendance. I wouldn’t be surprised if more and more people search for less popular national parks in explore, which will have interesting and important implications for park management and wildlife,” Sytsma said.
National parks and wilderness areas don’t just get more visitors during peak season. More people are choosing to use the trail systems during less busy times to avoid the crowds. Additionally, some parks are expanding their network of trails to accommodate more visitors.
The authors hope this study can help park managers consider different approaches to making parks accessible to both humans and animals. For example, managers might consider concentrating trails and human use in certain areas to reduce their total footprint, or placing restrictions on the time of year or days people can visit.
“Our results support the concentration of human activities in certain areas, because if you go above zero human activity and it will have an impact, you might as well go well above zero in certain areas and then have some impact. other areas where you have almost no human activity,” Pugh said. “In those areas, wildlife can go about their natural lives unaffected by humans.”