Our remote camera
recently captured P-13 and her 10-month-old kittens, P-28 and P-30, on a
kill in Malibu Creek State Park. The three of them spent two nights
sharing their meal of mule deer. After investigating more than 400 kill
sites during our study, we found that mule deer accounted for 95 percent
of mountain lion kills.
August 14, 2014
That mountain
lions have managed to survive at all in the Santa Monica Mountains of
California -- in the vicinity of the megacity of Los Angeles -- is a
testament to the resilience of wildlife, but researchers studying these
large carnivorous cats now show in the Cell Press journal Current Biology
on August 14 that the lions are also completely isolated, cut off from
other populations by the freeway. According to the researchers'
analyses, only one young mountain lion successfully dispersed into the
Santa Monica Mountains in a decade.August 14, 2014
Due to their almost complete isolation, the Santa Monica mountain
lions show dangerously low levels of genetic diversity, the study shows.
The circumstances have also made the Los Angeles-area cats incredibly
sensitive to individual behaviors. That single male that immigrated in
2009 and successfully mated substantially enhanced the genetic diversity
of the entire population all on his own.
Many of these phenomena, including very low genetic diversity and close inbreeding, have only been previously seen in Florida panthers, an endangered and completely isolated population of mountain lions," says Seth Riley of the National Park Service. "In our case, the fact that lions in the Santa Monica Mountains are completely surrounded by roads and development likely lead[s] to behaviors that would be rare or nonexistent if normal population and social processes could occur."
Among those behaviors, Riley and his colleagues found evidence of close inbreeding events between fathers and daughters and of intraspecific killing, even of offspring, siblings, and mates, all behaviors that the researchers suspect would be rare or nonexistent if sufficient movement between populations was possible.
While one male lion moved into the Santa Monica Mountains during the study period, to the researchers' knowledge not a single young mountain lion has successfully dispersed out, when normally 75% of young lions -- all of the males and half of the females -- would likely disperse. Riley says the one possible exception that proves the rule is a single male "who dispersed likely from the Santa Monica Mountains out to Griffith Park, where he lives in a tiny dead-end home range."
Increased connectivity is critical for the long-term survival of mountain lions and other wildlife in the region, Riley says. Unfortunately, no one was thinking about that 60 years ago when the Los Angeles freeway was built. As a result, Route 101 is a development corridor, with very little natural habitat on either side. Riley says the National Park Service, the California Department of Transportation, and other local agencies have been working for over a decade to try to obtain the funds for a wildlife crossing, ideally an overpass, for carnivores.
On the bright side, that one successful male immigrant shows that it might not take many successful crossings to get wild populations in much better shape at the genetic level. Otherwise, the future is easy to predict, Riley says.
"If wildlife connectivity is not considered and planned for, or improved in places like southern California where it has mostly been lost, large carnivores, which exist at very low densities and need to move great distances, will not persist."
Many of these phenomena, including very low genetic diversity and close inbreeding, have only been previously seen in Florida panthers, an endangered and completely isolated population of mountain lions," says Seth Riley of the National Park Service. "In our case, the fact that lions in the Santa Monica Mountains are completely surrounded by roads and development likely lead[s] to behaviors that would be rare or nonexistent if normal population and social processes could occur."
Among those behaviors, Riley and his colleagues found evidence of close inbreeding events between fathers and daughters and of intraspecific killing, even of offspring, siblings, and mates, all behaviors that the researchers suspect would be rare or nonexistent if sufficient movement between populations was possible.
While one male lion moved into the Santa Monica Mountains during the study period, to the researchers' knowledge not a single young mountain lion has successfully dispersed out, when normally 75% of young lions -- all of the males and half of the females -- would likely disperse. Riley says the one possible exception that proves the rule is a single male "who dispersed likely from the Santa Monica Mountains out to Griffith Park, where he lives in a tiny dead-end home range."
Increased connectivity is critical for the long-term survival of mountain lions and other wildlife in the region, Riley says. Unfortunately, no one was thinking about that 60 years ago when the Los Angeles freeway was built. As a result, Route 101 is a development corridor, with very little natural habitat on either side. Riley says the National Park Service, the California Department of Transportation, and other local agencies have been working for over a decade to try to obtain the funds for a wildlife crossing, ideally an overpass, for carnivores.
On the bright side, that one successful male immigrant shows that it might not take many successful crossings to get wild populations in much better shape at the genetic level. Otherwise, the future is easy to predict, Riley says.
"If wildlife connectivity is not considered and planned for, or improved in places like southern California where it has mostly been lost, large carnivores, which exist at very low densities and need to move great distances, will not persist."
Story Source:
The above story is based on materials provided by Cell Press. Note: Materials may be edited for content and length.
The above story is based on materials provided by Cell Press. Note: Materials may be edited for content and length.
Journal Reference:
- Seth P.D. Riley, Laurel E.K. Serieys, John P. Pollinger, Jeffrey A. Sikich, Lisa Dalbeck, Robert K. Wayne, Holly B. Ernest. Individual Behaviors Dominate the Dynamics of an Urban Mountain Lion Population Isolated by Roads. Current Biology, 2014; DOI: 10.1016/j.cub.2014.07.029
Cell
Press. "Freeways as fences, trapping the mountain lions of Los
Angeles." ScienceDaily. ScienceDaily, 14 August 2014.
<www.sciencedaily.com/releases/2014/08/140814124340.htm>.
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