A new study recently published by researchers from the National Park Service (NPS) found that mountain lions in the Santa Monica Mountains are becoming dangerously isolated by urban development. Penned in by freeways and neighborhoods, the population is now in danger of losing their genetic diversity. Perhaps even more worrying, experts say the cats have become much more violent.
“So far, National Park Service biologists have monitored more than 30 mountain lions with GPS radio-collars, enabling them to learn a lot about the animals’ ecology and behavior,” the NPS stated on its website. “The biggest threat to lion persistence in the Santa Monica Mountains is the loss and fragmentation of habitat by roads and urban development.”
The NPS began monitoring the Santa Monica population—which is not far at all from urban Los Angeles—in 2002. In a study published in the journal Current Biology, researchers say that after more than a decade of observation, the mountain lions are beginning to act strangely as a result of their isolation. The problem seems to be the large number of freeways in the area, especially the busy 101, which essentially trap the cougars within small pockets of wilderness. Mountain lions are fiercely territorial predators with a mobile instinct. Without the ability to establish ranges outside that of their families, this eventually causes conflict with siblings, parents, or offspring.
“There’s almost no movement out,” NPS ecologist and the study’s lead author Seth Riley told the Los Angeles Times. “That’s resulting in fathers mating with daughters, adult males killing close relatives or killing their offspring.”
Male lions generally leave their family groups 12 to 18 months after they are born, eventually finding their own territory and mates far away from where they started from. Instead, the males have no found themselves fighting with close relatives trying to carve out territory at home.
“Individual adult males can really dominate the reproduction in the population,” Riley told Southern California Public Radio.
Researchers call the new territorial behaviors aberrant and “bizarre.” Even playtime with cubs has turned violent. Scientists are unsure how much of this new behavior is caused by shrinking territory, and how much stems from mental and physical deficiencies as the population grows genetically weaker. According to the study, the genetic diversity of the Santa Monica mountain lions is the second lowest ever recorded for the species in North America.
Only a handful of cougars were documented to have escaped the freeway-locked region. One of these, a male lion that researchers named “P-22,” has become a local celebrity in Los Angeles and currently resides in Griffith Park. However, without the company of other cougars, this lone mountain lion now faces a different sort of isolation.
Researchers suggest that new, novel solutions are needed for small populations to survive, especially when it comes to the increasing number of man-made barriers across the country. Without some way to leave the Santa Monica Mountains, experts say that it is only a matter of time until the cougars there begin to exhibit more drastic disabilities as a result of their narrow gene pool.
Image courtesy National Park Service