November/December 1998 THIS MONTH'S ISSUE: Social Sciences Ecology Wildlife Biology Bioethics Neuroscience INDEX
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Bear Necessities Five-hundred miles overhead, a satellite keeps a watchful eye on four subjects in western Montana and northwestern Wyoming. As it crosses above a facility in Maryland, it dumps data accumulated over the past three days to a central computer. With a few keystrokes, the information is downloaded to Chris Servheen’s desktop and — presto — the last known movements of four Ursus arctos horribilis are pinpointed to within 200 feet. See related story: Living With Bears Servheen, grizzly bear recovery coordinator for Region 6 of the U.S. Fish and Wildlife Service and an adjunct associate professor of wildlife biology in UM’s School of Forestry, is testing the Global Positioning System as a better way to track bears. Collar-mounted GPS equipment locates a bear relative to various satellites, then transmits that information to the Argos satellite for storage and later downloading. The collar’s memory is then reset to collect more location readings. “GPS collars are better than traditional radio collars because they can be used day or night in all weather and allow precise tracking of specific animals relative to, say, roads,” Servheen says, “but they are bulky and most of their battery is used for transmitting data to Argos” rather than recording positions. So next spring Servheen and his team of biologists will try a modified, store-on-board collar on eight to 11 bears in areas near U.S. Highway 2 south of Glacier National Park and along roads near Yellowstone National Park. The new collars won’t have to transmit to Argos, so they can devote all their energy to taking hourly location readings. The information will be retrieved when the GPS unit is released from the bear by remote control and falls off. Grizzly islands Only 800 to 1,000 grizzly bears — listed as a threatened species since 1975 — remain in the lower 48 states, according to Fish and Wildlife Service estimates. Instead of inhabiting the vast spaces they once did, grizzlies now are found in only five scattered locations in Montana, Wyoming, Idaho and Washington, a mere 2 percent of their historical range south of Canada. Only two areas — the Greater Yellowstone ecosystem and the Northern Rocky Mountain ecosystem, which includes Glacier National Park and the Bob Marshall Wilderness — have populations of several hundred bears. The remaining areas contain only five to 50 bears each. Servheen’s purview covers the four states plus the Canadian provinces of Alberta and British Columbia, where grizzly bears are more abundant. Since bears don’t respect political borders, he says, “we take an ecosystem approach to management. We have good and close relations with our Canadian colleagues because we depend on each other” for information and coordination. To ensure the continued existence of Ursus arctos, the Fish and Wildlife Service’s objective is to establish new populations where possible and nurture existing ones. Servheen’s two management priorities currently are the restoration of grizzlies in the Selway-Bitterroot Wilderness between Idaho and Montana and the continued recovery of bears in the Greater Yellowstone ecosystem, which now boasts a healthy population of 400 to 600 bears. One problem in grizzly bear recovery is balancing numbers with available territory. The United States has seen little or no movement of grizzly bears among the separate populations for a long time. So, as part of the federal Grizzly Bear Recovery Plan, Servheen and his team are looking at the potential to establish linkages between separate bear habitats. They use geographical information system models that score levels of human activity in areas between bear habitat. The results indicate whether bears could move between ecosystems. Where opportunities do exist, they plan ways to preserve them. Mostly this means working with local landowners and county governments to give residents the information they need to live with bears. “We see some opportunities for linkages, but many are precluded by the amount of human activity,” Servheen says. “For instance, between the Rattlesnake Wilderness, which leads to the Bob Marshall and Glacier complex, and the Bitterroot Mountains bears have to cross Interstate 90 and U.S. Highway 93. That’s pretty tough.” Servheen expects to have a report on linkage possibilities out by next summer. Lethal barriers “Highways are the most significant factor in the fragmentation of habitat for many animals,” Servheen says, “and the fact that animals must cross them to get where they need to makes them a huge safety issue for both humans and animals.” Such studies also may help identify the most appropriate type of mitigation structure for road builders. Putting the road underground in strategic areas, for instance, may be much more effective than trying to build tunnels or bridges for animals to use. Servheen’s job is a difficult and political one. As Environmental Impact Statement team leader for the restoration of grizzly bears to the Selway-Bitterroot ecosystem, which includes the largest wilderness areas in the contiguous United States, he has spent hundreds of hours juggling often contentious input from federal, state, local and tribal agencies, landowners, environmental organizations and concerned citizens. The final EIS, due out in January, contains information on the history of bears in the region, habitat suitability, impacts of bears on various human activities, and the costs and effects of four alternatives to restore grizzlies to the area. The preferred course of action would be to establish an experimental, nonessential population of 20 to 25 bears moved in from Canada and other source populations over five years. Under this plan, Servheen says, “it would take about 100 years to get a population of 300 bears, since females typically only reproduce every three years if conditions are good.” But even assuming the EIS receives approval from the Department of the Interior, there is no guarantee of funding and, of course, no guarantee that public controversy will abate. “On the subject of grizzly bear introduction, no one is neutral,” Servheen says. |
