Species and Sprawl: A Road Runs Through It
Species and Sprawl: Mountain Lions
Not unless you were the last lion on Earth!”
When P1, an adult male mountain lion who roams the 620 sq km Santa Monica Mountains just outside Los Angeles, took stock of his mating options last summer, his pickings were slim. As far as ecologists are aware, his choice, P2, may have been the only female in existence in the entire range.
P6, a female, is one of four cougar cubs born in the Santa Monica Mountains last August.
There are other fish in P1’s sea, which is a chain of protected areas to the north of the coastal range. But P1 can’t get to these areas easily. A six-lane freeway, U.S. 101, divides the Santa Monicas from the gently sloping Simi Hills directly to the north. Above the Simi Hills, Highway 118 bars safe passage into the Santa Susana Mountains. Finally, for P1 to get from the Santa Susanas to the lion-dotted paradise of Los Padres National Forest, a vast coastal range that reaches nearly to the Bay Area, he would have to seek out and sneak through green corridors of undeveloped land perhaps just 20 m wide.
However reluctantly paired, P1 and P2 produced four lion cubs in late August, according to Seth Riley, a National Park Service wildlife ecologist who has been tracking the two via radio and GPS collars for two and a half years. But Riley and other scientists and conservationists worry that the Santa Monica range is too small for at least six lions to coexist and reproduce. In fact, in crowded California, sprawl is now the main threat to 66 percent of the state’s 286 endangered species.
Many believe that the animal-friendly antidote to California’s urbanization is to make the corridors—called linkages—between disparate patches of wild lands truly useable by many different species. Currently, the South Coast Missing Linkages Project is taking the charge seriously. They are working to identify, unite, and protect Southern California’s 15 most threatened habitat connections before new development encroaches. Establishing a crossing at Highway 101 is among the project’s highest priorities.
A Home on the Range
As far as cougar habitat goes, the Santa Monicas aren’t half bad—literally. About 300 of its 620 sq km of craggy, scrub-and-oak-dotted mountains remain open to development, which is still sparse despite continuous pressure from Los Angeles’s ever-eager appetite for housing. “At this point,” says Riley, “there seems to be quality habitat and plenty of deer to eat.”
While P2 requires only about 100 sq km of land, P1’s space needs—about 400 sq km— gobbles up nearly the entire Santa Monica range. “Adult male lions don’t tolerate a lot of other adult males in their area,” says Riley. Since male mountain lions, like all cats, do not raise their young, it’s unlikely that P1 would recognize his two sons, and he may even eliminate this competition. “Certainly they’ll fight,” says Riley. ”Sometimes they’ll even kill each other.”
All told, Riley predicts, the Santa Monicas can support fewer than 10 lions. “But 10 lions is not a population,” says Riley. “For genetic and demographic reasons, that’s just not enough.” Inbreeding, and therefore genetic mutation and disease, increases when populations of large carnivores like cougars, bears, wolves, and wolverines become isolated by development and agriculture. Such problems have sidelined Florida panthers, a subspecies of mountain lion, whose population has been hovering near 50 for decades. Since 1988, Texas cougars have periodically been introduced to Florida to increase genetic diversity.
