The amount of total space a bear needs can vary depending on the species, sex, age, habitat quality, and food availability. While parks can provide core habitat, individual bears often use landscapes that extend beyond park boundaries. In addition, habitat outside of parks can be crucial for young bears dispersing and looking for new territory and to maintain genetic diversity in a population. Urban areas, roads, and other man-made barriers affect the ability of bears to move between parks and other areas of high-quality habitat. The National Park Service is involved in a number of collaborations to improve the habitat and connections in the larger landscapes that bear populations require.
The National Park Service co-leads the Great Northern Landscape Conservation Cooperative (LCC), a partnership that works across jurisdictional boundaries to share science and practices to provide conservation solutions in the northwest United States and western Canada. The Great Northern LCC has used genetic analysis to identify isolated bear populations and developed recommendations for linking those populations (for more information, see the "De Fragmenting the West" webinar). The LCC also works with partners to identify roads that inhibit wildlife movement and to create linkages so that bears and other wildlife can safely move throughout the landscape to find food and shelter and reproduce.
The return of black bears to Big Bend National Park was possible because the park protected bear habitat even when there were no bears to use it. Before Big Bend National Park was established, trapping and killing had made bears rare in the region. After the park was established, bears occasionally entered the park from Mexico, but they did not remain in the park. For some reason still unknown to biologists, bears began to recolonize the park starting in the late 1980s. This recolonization was possible because the park protected bear habitat, allowing bears to move through the landscape connecting the park to bear habitat in Mexico.
Bears need large areas of habitat to obtain food and shelter through various seasons. Taken together, this means that healthy bear populations need very large areas of contiguous habitat. Roads present a dangerous barrier to bear movement. Each year, hundreds of bears are killed by cars. Sometimes, these accidents are fatal to the human occupants as well. However, bears are able to take advantage of bridges and culverts to safely cross roads. Departments of Transportation are beginning to work with parks to incorporate "critter crossings" with specific needs of wildlife in mind. The National Park Service partnered with the U.S. Forest Service to develop the Wildlife Crossing Toolkit to help federal land managers contribute to the design of roads that take wildlife needs into account.