Report looks at recreation effects on 15 species
For people who enjoy exploring wild places, encountering wildlife can be a highlight of an outdoor excursion.
Animals are often glimpsed as they run or fly away, alarmed by the presence of humans. Although outdoor enthusiasts enjoy seeing animals in their habitat, the growing popularity of outdoor recreation and the disturbance it causes wildlife may threaten the health or survival of some species.
Outdoor recreation opportunities and participation have increased in Washington state in recent decades, and got a significant boost during the pandemic. Consequently, the effect of recreation on wildlife behavior, health and populations is a growing conservation concern.
Those concerns were examined in a recent report completed by Home Range Wildlife Research, a Methow Valley-based research organization, in collaboration with Conservation Northwest, based in Bellingham.
Here in the Methow Valley, the expansion of outdoor recreation in recent years has been unmistakable. Popular trailhead parking lots are overflowing, new mountain bike trail systems have been developed, fragile terrain at high elevations has been trampled by hikers.
What is not as evident is the impact of the growing presence of people on animals that live in wild areas. The report, “Recreation and Wildlife: Considerations for Conservation,” looks at the available science for 15 species found in Washington, synthesizing current knowledge about the impacts of recreation activities on wildlife and providing recommendations for sustainable recreation management.
Washington residents “hold deep appreciation for the diverse landscapes and … plethora of wildlife,” said Kurt Hellman, advocacy associate for Conservation Northwest, in an online blog about the report.
“As participation in outdoor recreation continues to grow, I’ve wondered how ecosystems are impacted by the rising number of people spending time in nature. And specifically how my presence, along with others, affects the wildlife that call these places home.”
The new report seeks answers to those questions, Hellman said. “The main takeaway is clear — recreation can have negative impacts on wildlife. These impacts range from temporarily displacing species to posing serious challenges to a population’s viability.”
Wildlife/recreation dynamics
Home Range Wildlife Research reviewed 66 papers and more than 50 scientific articles related to the impacts of recreation on 15 species found in Washington. The report seeks to better understand wildlife/recreation dynamics in order to guide conservation and management approaches that mitigate negative effects of recreation on wildlife.
“This is particularly important for the western United States, which holds both the largest percentage of public lands and protected wildlife habitat and is experiencing some of the highest population growth rates,” the report said.
“With nearly 19 million acres of public land and another 6 million acres of tribal land, Washington holds appealing opportunities for a growing number of outdoor recreationists and boasts a remarkable set of ecosystems,” the report said.
The report looked at impacts of both motorized and non-motorized activities, with the exception of hunting. The report said effects on wildlife from hunting are already closely regulated by federal, state, and tribal agencies.
The species studied include bighorn sheep, caribou, elk, mountain goats, mule deer, black bear, Canada lynx, grizzly bears, mountain lions, wolves, wolverines, bald eagles, golden eagles, marbled murrelets and sage grouse.
“Most animals in the report might have some threshold at which they tolerated recreation, but where that line is unclear,” said Becca Windell of Home Range Wildlife Research, and one of the report’s authors. She said Home Range was contracted to review all of the available literature on wildlife-recreation dynamics for the selected species to help inform Conservation Northwest’s Wildlife-Recreation Coexistence Program.
The review of existing science on recreation/wildlife dynamics identified common patterns in wildlife responses to human recreation:
• Animals tend to have stronger responses to less predictable forms of recreation, such as people walking off established trails.
• Pregnant females and young tend to be more vulnerable to negative impacts from recreation.
• Season is important, and wildlife responses may differ between summer and winter.
• Habitat generalists (animals able to survive in a wide variety of environmental conditions) are less vulnerable than habitat specialists (animals that require a narrow range of environmental conditions or have limited diets).
• Wildlife species that are capable of altering their patterns may become more active at different times of day or night to avoid humans.
• As the intensity of recreation increases, so does the impact to wildlife.
• Non-motorized recreation is more disturbing to most wildlife than motorized activities. However, motorists can cover more ground, thus increasing the geographic extent of their impact.
Impacts on wildlife
One of the more difficult aspects of recreation/wildlife dynamics to understand is how short-term disturbances to animals may impact the long-term well-being or survival of a species, Windell said. “It’s hard to know how much those changes in behavior … are affecting populations,” she said.
For instance, one of the most common behaviors among animals — fleeing when they encounter humans — can have a wide range of impacts. Animals in flight experience stress and its negative physiological effects; they may lose opportunities for resting and feeding; they may be driven out of preferred habitats, including areas where they reproduce and rear young; and in some cases they may abandon offspring. Depending on how sensitive or vulnerable a species is, these effects could have long-term impacts on a population’s survival.
Some animals are better able to adapt to human presence. Mule deer, one of the Methow Valley’s signature species, are known to habituate to humans and short-term behavioral responses to recreation are reduced in some cases, the report said. Mule deer may also become more active at night to avoid humans. But when high-intensity recreation overlaps with important fawning, migration, and wintering areas, the deer population could be adversely affected.
Among wildlife in or around the Methow Valley, wolverines are an example of a particularly vulnerable species, Windell said. Wolverines give birth and raise their young in dens dug into mountain snowpack in winter — and loss of snowpack due to climate change is expected to reduce wolverine habitat by a third in the next three decades.
The Cascade Mountains above the Methow Valley provide the snowpack that is essential to wolverine survival, while also attracting a variety of outdoor winter activities including snowmobiling, cross-county skiing, and heli-skiing (the Methow has the only commercial heli-skiing operation in Washington).
Studies of wolverines evaluated in the report focus on winter recreation, and show that wolverines’ efforts to avoid off-road motorized activities results in a loss of habitat, including areas where females create dens to raise their kits. Females may move their dens more frequently as a result of motorized recreation.
No studies have documented the impacts of noise from snowmobiles and helicopters on wolverines, but “it has been suggested that wolverines are disturbed by both site-specific use and the noise produced by snowmobiles, which may cause denning females to abandon dens and reduce reproductive success,” the report said.
The shrinking mountain snowpack due to climate change “will further concentrate the areas where wolverines and winter recreational activities overlap,” the report notes.
Recommendations
Like wolverines, many of the species discussed in the report are imperiled in Washington state, and “even a small amount of range overlap with recreation in important habitats and during sensitive periods could prove detrimental for animals especially sensitive to human disturbance,” the report said.
“We know that coupled with changing climate and continued habitat loss, these impacts from recreation, no matter how small, can prove detrimental to species,” Hellman said in his Conservation Northwest blog.
While there is still more to understand, the report “posits that with the right data, knowledge and management action, recreation and wildlife can coexist,” Hellman said. In his blog, he described “critical next steps” outlined in the report for sustainable recreation management:
• Identify recreation and wildlife overlap. We need to know where heavy recreation use intersects important wildlife habitat. These areas are where public land managers should seek to improve wildlife and recreation coexistence by mitigating known negative impacts to wildlife.
• Measure recreation use on public lands. There’s a dire need to collect accurate information for how many people are using recreation areas and when. This data will lead to a better understanding of the short and long-term effects of various recreation activities on wildlife.
• Protect critical wildlife spaces. Quality habitat that is free of major disturbance (known as refugia) is vital for certain species’ survival, especially for sensitive species such as caribou, sage-grouse, wolverine, and mule deer. Animals are particularly vulnerable while denning, rearing young, or trying to survive the winter months. Identifying and protecting key wildlife corridors is essential, as wildlife need to move across landscapes.
• Implement management action. Even with limited data, land managers need to respond to the impacts that recreation has on wildlife. Adaptive management approaches based on the latest science can provide a good starting point and be responsive to more research as it becomes available.
As individuals, Windell said, people who want to reduce their impact on wildlife can stay on established trails as much as possible, limit nighttime activities in the wild to avoid interfering with animals’ nocturnal behavior, and respect seasonal closures in wildlife areas.
Home Range Wildlife Research and Conservation Northwest are planning a presentation (no date set yet) for recreation organizations in the Methow Valley to share details of the report, answer questions, and gather feedback, Windell said. The report is available at: conservationnw.org/news-updates.
