What’s Next for America’s Bears
With the Yellowstone and Glacier populations likely secured for the next 500 years, the USFWS hopes to move forward with delisting grizzlies in those areas, and redirecting resources to help preserve and augment other recovery zones. That could be the key to future grizzly survival. “More occupancy in ecosystems increases the resiliency of the population as a whole,” says Servheen. “Genetic diversity is valuable, of course, but the real threat to grizzly bears was demographic collapse when populations got so small and isolated, as they were before 1980.” Grizzly bears reproduce more slowly than almost any other land mammal in North America: Mother bears typically produce a litter of two cubs, raise them for two years, and may not produce another litter for three to four years after that. The vast potential home ranges of males (as much as 500 square miles) can make simply finding a mate difficult. If a system with too few bears doesn’t produce enough female offspring, it could collapse completely.
When officials first pursued delisting in 2007, environmental groups sued, arguing bear populations were still too fragile. Federal courts agreed, citing climate change as a threat to key food sources like the whitebark pine, which pine beetles have ravaged. But while Servheen acknowledges the risk, he believes bears are uniquely predisposed to handle changes—and could adapt successfully to climate change.
“Grizzly bears and black bears are very adaptable species; they live in a wide range of habitats, and they’re not specialists on particular foods,” Servheen says. “Some animals, like wolverines, require snowy habitats. If snow conditions decline, it may have dramatic impacts. While climate change may affect the seasonal distribution of foods, some might actually have longer growing seasons, and bears could change the timing of their denning to accommodate the new food situation. We’re monitoring for baseline data now, but so far, bears are doing pretty well.”