National Parks research part of restoration plan
A wide range of evidence shows that grizzly bears roamed the North Cascades for thousands of years, but it may never be clear how numerous they once were, according to a recently released study by the National Park Service.
In early 2017, a draft Grizzly Bear Restoration Plan was released for the North Cascades Ecosystem by the National Park Service and the U.S. Fish and Wildlife Service. In public comments submitted in response to the restoration plan, some people expressed doubts that a viable grizzly population ever existed in the North Cascades.
The report completed this summer by the National Park Service sought to address those doubts by examining diverse sources of information about the prehistoric (prior to 1800), historical (prior to 1950), and recent grizzly bear presence in and around the North Cascades.
“Estimates of historical grizzly bear distribution and density in the North Cascades have remained uncertain and even puzzling, but biologists, historians and park managers generally maintain that populations originally extended throughout the Cascade Range and most other parts of Washington,” the report stated.
Titled “A Synthesis of Historical and Recent Reports of Grizzly Bears (Ursus arctos) in the North Cascades Region,” the report examines archeological and ethnographic literature, records from the region’s 19th century fur trade, and historical and recent accounts of grizzly bears. It focuses on the North Cascades ecosystem, which is one of six grizzly bear recovery zones in the lower 48 states identified by U.S. Fish and Wildlife Service.
The ecosystem includes about 6.3 million acres in the United States, including areas of Okanogan, Whatcom, Skagit, Snohomish, Chelan, Okanogan and King counties. It also includes 2.4 million acres in British Columbia.
After examining a variety of sources to evaluate the historical presence of bears, the report concluded that “the broader history of grizzly bear distribution and abundance in the Pacific Northwest is nearly as elusive and sensitive as the bears themselves are known to be today.”
The report came to five principal conclusions:
• Archeological evidence confirms that prehistoric grizzly bears lived in lowland regions surrounding the North Cascades ecosystem. Evidence of grizzly bear remains have been uncovered on Whidbey Island and throughout the Columbia basin, although their presence in the North Cascades is “enigmatic” due to the lack of archeological data, the report said.
“Because the species is able to live in a wide range of habitats, their range would have most certainly included the North Cascades as well as most other lowland areas of Washington and southern BC,” the report said.
• Studies of First Nations living in and around the North Cascades show that grizzly bears had a role in spiritual and hunting traditions in areas where the bears have since been absent. Accounts from First Nations indicate they had respect and fear for the bears, and that they hunted grizzly bears less than other species. The population of grizzly bears may have been suppressed by competition with the region’s First Nations people for food sources such as salmon, deer and elk, and berries.
• Fur trade records confirm presence of grizzly bears in lowland regions surrounding the North Cascades ecosystem between 1826 and 1857. A total of 3,188 grizzly bear pelts were harvested from regional trading posts during that period, and that is considered a conservative estimate because recordkeeping was not precise. It does not appear that trade reached far into the core of the North Cascades range, however, and the study’s authors said it was difficult to determine with any certainty where the pelts were obtained.
• Recent observations confirm grizzly bear presence within the ecosystem, especially along the east of the North Cascades crest. Researchers compiled accounts of observations grizzly bears or their signs within the North Cascades between 1859 and 2015. A total of 208 observations, including 165 sightings that were confirmed or “highly reliable” were recorded. Sightings or signs of grizzlies appear to be concentrated in areas with whitebark pine, subalpine larch and open subalpine terrain. This could be related to the importance of whitebark pine seeds as a food source or the reduced presence of humans at higher elevations, the report said.
The observations “show that grizzly bears persist in small numbers at apparently very low densities. It is not known whether reproduction has occurred since the last confirmed cub sighting on Lake Chelan in 1991,” the report said.
• The North Cascades range has provided a relatively unaltered habitat for any remnant grizzly population. Cultural and historical records confirm that in recent memory the bears were limited to alpine and subalpine elevations and rarely occurred in lowland regions, especially west of the current boundary of the North Cascades National Park, the report concluded.
Of all the factors contributing to the current state of grizzly bears in the Pacific Northwest, the most influential is human population growth, the report said.
“Given the extremely slow reproductive rate of grizzly bears and the surrounding human-developed landscapes that isolate the North Cascades ecosystem from other occupied patches, grizzly bears have almost certainly persisted decades past the tipping point of a viable population,” the study stated. “The grizzly bear population is thus highly at risk of eventual extirpation.”
While there are viable populations of grizzly bears in some parts of British Columbia, the Fraser River, two railroads and the TransCanada Highway are considered major barriers to natural movement of bears into the North Cascades ecosystem, the study said.
The report was published through the Park Service’s Natural Resource Stewardship and Science office. It is available in digital format at irma.nps.gov/DataStore/Reference/Profile/2253705.