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Where are the North Cascade grizzly bears?

By: Kimberly Romain
Trip Date: Summer 99

There I stood on a ridgeline looking down into another astonishing alpine basin. I had not seen another soul in 3 days, and was feeling rapture with myself and the wilderness I was hiking through. The snowline finally had receded enough to allow the glacier lilies, and spring beauties, then the alpine lupine and Indian paintbrush to flower, which cast a colorful hue over the lush green meadow that lie in front of me. Aside from the main trail I had traveled on, the air, the land, and the terrain felt wild. This site in the Pasayten Wilderness was recommended, along with other areas within the North Cascades National Park and the Mt. Baker/Snoqulamie Wilderness, because it is grizzly bear habitat. This area was also described to me as one of the most remote and intact wilderness regions, not only within Washington, but within the lower 48. The question that raced through my mind as I looked upon the basin below was, "where are the North Cascades grizzly bears?"

Grizzly bears are opportunistic animals that roam the hillsides, looking for the lushest of meadows, the plumpest of berries, and the best of mates. Males often have homeranges upwards of 400 km2 (150 sq miles) and female homeranges can be up to 200 km2 (80 sq miles). Grizzly bears of the North Cascades most likely resemble other interior populations of brown bears (such as those of the Selkirk mountains), and are relatively small in size, approximately 150 to 400 lbs, females being smaller than males. Unlike the 1000 pound coastal brown bears in northern B.C. and Alaska who feed seasonally on salmon, interior grizzly bears are more dependent on berries, pine nuts, insects, vegetation, and an occasional winter kill or scavenged carcass, to accumulate fat reserves. It is necessary to realize how important fat reserves are for bears. During hibernation, they will lose up to 50% of their body weight, burning a good percent of the fat accumulation they collected during the summer and fall. They must have enough energy in the spring, to emerge from their den sites (with or without cubs), and travel to areas rich in spring forage. Habitat must be able to support the bears by providing these highfat, nutritious food items.

Based on the availability of food and habitat in the North Cascades, the Interagency Grizzly Bear Committee (IGBC) of Washington State has estimated that approximately 200 grizzlies could inhabit the North Cascade ecosystem.

Although the North Cascade mountains are known for their steep terrain and jagged peaks, the 16,000 sq. miles of the North Cascade mountains are bounteous with avalanche chutes blanketed by yellow glacier lilies (the roots which are excavated by grizzlies for the potato-like corm), subalpine basins that harbor marmot and ground squirrel refuge (a possible grizzly bear delicatessen), talus slopes that invite aggregations of alpine army cutworm moths (a favorite high fat grizzly bear food in Yellowstone National Park), and alpine meadows are plentiful with huckleberries (a high sugar food source in the late fall). So again I ask, "where are the grizzlies?"

Grizzly bears are protected as an endangered species in Washington (USFWS 1981), and classified as sensitive in BC (BC Ministry of Environment 1995). Despite this protection, they are still struggling to survive as a small population in the North Cascades ecosystem. Little is known about the status of the grizzly bears in Washington, and across the border into Canada. Sitings by biologists, recreationalists, and hunters have identified grizzly bears, tracks, excavations (large areas dug up for food), and cache sites (large areas where food is buried for later consumption). There have been 107 confirmed sitings between 1986 and 1999 based on evidence described to fit the characteristics of a grizzly bear. Although this information is important, the documentation does not help us understand, nor help recover the small population of grizzly bears that still may exist in the North Cascades.

Baseline data is needed. How many grizzly bears exist in the North Cascades, if any? How many female grizzly bears are in the North Cascades, and are they producing offspring? What is limiting the growth of the grizzly bear population? Could it be the lack of food, the lack of females, or possibly that cubs are not surviving to reproduce on their own? Any or all of these factors may be holding the grizzly bears of the North Cascades at very low population numbers; they could go extinct at any time. My studies are using DNA hair-sampling methods to address some of these questions.

Conservation Genetics and DNA sampling techniques are relatively new in wildlife management and their applications are diverse. In Japan, DNA studies are being used to identify threatened and endangered whale species sold as meat products in the marketplace. While similar studies to my own include genetic work on Andean Spectacle bears, wolverines, and lynx. The idea of these studies are to use non-invasive hair sampling techniques to snag hair from animals, without ever seeing (unfortunately), touching, or capturing the animal of interest. Once hair samples are collected, DNA extracted from the hair follicle can then be analyzed in the laboratory for species, sex, individual identification, genetic diversity, and even parent-offspring relationships. This analysis will help us determine the presence of grizzly bears, the sex ratio of animals sampled, and the minimum numbers of bears present in our study area.

Field Work: We collected hair samples between May and September. A hair-snag site is set up as a single strand of barbed-wire around a clump of trees. The wire is positioned about knee height (approximately 50 cm) from the ground, so that small animals can easily walk under the wire, and large animals can easily walk over the wire. A pungent, liquid attractant is placed in the center of the perimeter fence, either on a downed log or on a tree. In contrast to traditional baiting methods, our attractant provides no reward that would habituate bears to a food source, to humans, or to the site itself.

When curious bears approach the site, loose hairs are snagged by the barbed wire. This technique was tested at Washington State University’s Bear Research Facility and was found not to harm bears; in fact, barbs were found to pull only 3 mm of hair from the animal without breaking the skin. We collect hairs delicately with sterilized forceps, and the samples were placed in envelopes to be dried and sent to the laboratory for genetic analysis. It is important to revisit a site within 14 days after the initial setup, because after this critical window of time, the DNA within a hair sample will begin to degradade. Sites are left up for a total of 4 weeks, then dismantled and removed.

Laboratory Work:To identify presence and minimum numbers of grizzly bears in the North Cascades, hair samples are analyzed for species identification. Once the DNA is removed from the hair follicle, it is replicated using a process called Polymerase Chain Reaction (PCR), thus exponentially increases the amount of DNA we have to work with. Brown bear samples can then be separated from black bear samples using new genetic technology called Applied Biosystem (ABI) fluorescent labeling systems (see figure 1). To identify how many individuals we sampled, we use microsatellite analysis, which identifies repeat sequences on the DNA (see figure 2). Think of the microsatellite analysis as DNA fingerprinting; no two individuals are exactly alike. DNA fingerprinting also allows us to measure how closely related individuals are to one another (parent to offspring), and how their genes compare to other brown bear populations in surrounding areas of the U.S. and in Canada.

Protecting wilderness means protecting the species of both plants and animals that inhabit the land. I feel it is important to realize that since humans hunted many populations of wildlife nearly to extinction, it is our responsibility to care for the land in a way that allows for the restoration of wildlife populations and encourages them to thrive in their native habitat. To ultimately help grizzly bear recovery efforts in the North Cascades, we first need to know and understand the population that may still exist. This knowledge will help us make practical decisions on how to manage modern human impacts, from campsite and trail development to resource extraction, on wilderness and public lands of Washington. I hope my study will enable us to answer the question "where are the grizzlies", and help us gain a better understanding of the North Cascade grizzly bear population and their recovery needs. If you have any further questions or comments, please feel free to contact me at Washington State University- Department of Natural Resource Sciences.