Featured Research

from universities, journals, and other organizations

Freeways as fences, trapping the mountain lions of Los Angeles

Date:
August 14, 2014
Source:
Cell Press
Summary:
That mountain lions have managed to survive at all in the Santa Monica Mountains of California -- in the vicinity of Los Angeles -- is a testament to the resilience of wildlife, but researchers studying these large carnivorous cats now show 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.

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.
Credit: National Park Service

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.

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."


Story Source:

The above story is based on materials provided by Cell Press. Note: Materials may be edited for content and length.


Journal Reference:

  1. SethP.D. Riley, LaurelE.K. Serieys, JohnP. Pollinger, JeffreyA. Sikich, Lisa Dalbeck, RobertK. Wayne, HollyB. 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

Cite This Page:

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>.
Cell Press. (2014, August 14). Freeways as fences, trapping the mountain lions of Los Angeles. ScienceDaily. Retrieved October 20, 2014 from www.sciencedaily.com/releases/2014/08/140814124340.htm
Cell Press. "Freeways as fences, trapping the mountain lions of Los Angeles." ScienceDaily. www.sciencedaily.com/releases/2014/08/140814124340.htm (accessed October 20, 2014).

Share This



More Science & Society News

Monday, October 20, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Traditional Farming Methods Gaining Ground in Mali

Traditional Farming Methods Gaining Ground in Mali

AFP (Oct. 20, 2014) He is leading a one man agricultural revolution in Mali - Oumar Diatabe uses traditional farming methods to get the most out of his land and is teaching others across the country how to do the same. Duration: 01:44 Video provided by AFP
Powered by NewsLook.com
Your Birth Season Might Determine Your Temperament

Your Birth Season Might Determine Your Temperament

Newsy (Oct. 20, 2014) A new study says the season you're born in can determine your temperament — and one season has a surprising outcome. Video provided by Newsy
Powered by NewsLook.com
How Nigeria Beat Its Ebola Outbreak

How Nigeria Beat Its Ebola Outbreak

Newsy (Oct. 20, 2014) The World Health Organization has declared Nigeria free of Ebola. Health experts credit a bit of luck and the government's initial response. Video provided by Newsy
Powered by NewsLook.com
Ebola Worries End for Dozens on U.S. Watch Lists

Ebola Worries End for Dozens on U.S. Watch Lists

Reuters - US Online Video (Oct. 20, 2014) Forty-three people who had contact with Thomas Eric Duncan, the first person diagnosed with Ebola in the U.S., were cleared overnight of twice-daily monitoring after 21 days of showing no symptoms. Rough Cut (no reporter narration). Video provided by Reuters
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:

Strange & Offbeat Stories


Science & Society

Business & Industry

Education & Learning

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile: iPhone Android Web
Follow: Facebook Twitter Google+
Subscribe: RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins