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<a class="postlink" href="http://www.ocregister.com/articles/lions-671903-california-study.html" onclick="window.open(this.href);return false;">http://www.ocregister.com/articles/lion ... study.html</a>
Orange County’s mountain lions are on the brink, and the only way to pull them back may soon become introducing lions from elsewhere, according to a new study.
Highways and housing projects have hemmed in Southern California’s lions, dividing them into two major groups. One is in the Santa Ana Mountains, the other is in the Eastern Peninsula Range in San Diego County.
Scientists know of only one lion that has successfully crossed between the two regions since 2001, and that lion produced four offspring. Only one is still alive, a female with two offspring, who may or may not disperse.
The odds are not in the lions’ favor, according to the study, which was led by UC Davis researchers and published Wednesday. So severe are the threats posed by speeding cars and gun-armed landowners shooting livestock-killing lions that a Southern California lion today only has a 55.8 percent chance of still being alive a year from now.
That survival rate is lower than many lion populations in the Western U.S. that are hunted for sport or to control attacks on livestock.
Though hunting lions is illegal in California, the Southern California population could be snuffed out simply by the lifestyle of the more than 20 million people who now live here, as those people build homes and roads, drive their cars and increasingly isolate the lions.
“The assumption that populations do fine on their own when not hunted is not true in Southern California,” said Winston Vickers, the lead author on the study. “All these sources of mortality are related one way or another to our patterns of human development and human behavior.”
In Orange County, lions are almost always killed by cars. According to the study, the highest concentrations of lion deaths was along the 241 toll road and the Ortega Highway, with additional deaths on the 261 toll road -- all high-speed roadways bordering or cutting through the Santa Ana Mountains.
In San Diego County, lions were more often killed by landowners who secured depredation permits to eliminate lions that preyed on livestock.
Though the number of Southern California lions killed by people with depredation permits has declined in the last decade, the number killed by vehicles has only increased.
The study, published in the online science journal PLOS ONE, detailed scientists’ efforts to track lions between 2001 and 2013 using GPS radio collars. A total of 74 lions were studied, and only one left the study area, crossing from the San Diego County into Mexico.
The paper estimates between 17 and 27 lions live in the Santa Ana Mountains. With limited breeding partners, those lions are becoming increasingly inbred, threatening their genetic diversity and, ultimately, their survival.
“When landscapes get so fragmented that animals can’t get around, ecosystems unravel,” said Scott Morrison, director of science for The Nature Conservancy in California, and a coauthor of the study. “This study is a wake up call, to avoid developing in ways that create these crises with wildlife.”
Lions were long ago killed off in the eastern U.S., except for a small population of Florida panthers. Those, too, nearly went extinct, until wildlife managers brought in some Texas lions in the 1990s to breed with the Florida animals and increase both the population and the diversity in the gene pool.
Such measures may soon be necessary in Southern California.
“We’re headed in that direction at a steady and maybe accelerating pace. We have chances to attempt to correct the situation, but those will go away,” Vickers said.
The first solution is to make highway crossings safer and more lion-friendly, while blocking lions from the rest of the highway with fences, Vickers said. A good example is the 241 toll road, where the Transportation Corridor Agency is building a fence.
It’s easy to think that such a large, mobile, speedy animal -- the king of the animal kingdom -- would be invincible. But after more than a decade spent studying the animals, Vickers has come to realize how defenseless they really are.
“Mountain lions are an indicator of the power we have to disrupt ecosystems,” Vickers said. “They’re way more vulnerable to us in our day-to-day way we live in Southern California than we think.”
Orange County’s mountain lions are on the brink, and the only way to pull them back may soon become introducing lions from elsewhere, according to a new study.
Highways and housing projects have hemmed in Southern California’s lions, dividing them into two major groups. One is in the Santa Ana Mountains, the other is in the Eastern Peninsula Range in San Diego County.
Scientists know of only one lion that has successfully crossed between the two regions since 2001, and that lion produced four offspring. Only one is still alive, a female with two offspring, who may or may not disperse.
The odds are not in the lions’ favor, according to the study, which was led by UC Davis researchers and published Wednesday. So severe are the threats posed by speeding cars and gun-armed landowners shooting livestock-killing lions that a Southern California lion today only has a 55.8 percent chance of still being alive a year from now.
That survival rate is lower than many lion populations in the Western U.S. that are hunted for sport or to control attacks on livestock.
Though hunting lions is illegal in California, the Southern California population could be snuffed out simply by the lifestyle of the more than 20 million people who now live here, as those people build homes and roads, drive their cars and increasingly isolate the lions.
“The assumption that populations do fine on their own when not hunted is not true in Southern California,” said Winston Vickers, the lead author on the study. “All these sources of mortality are related one way or another to our patterns of human development and human behavior.”
In Orange County, lions are almost always killed by cars. According to the study, the highest concentrations of lion deaths was along the 241 toll road and the Ortega Highway, with additional deaths on the 261 toll road -- all high-speed roadways bordering or cutting through the Santa Ana Mountains.
In San Diego County, lions were more often killed by landowners who secured depredation permits to eliminate lions that preyed on livestock.
Though the number of Southern California lions killed by people with depredation permits has declined in the last decade, the number killed by vehicles has only increased.
The study, published in the online science journal PLOS ONE, detailed scientists’ efforts to track lions between 2001 and 2013 using GPS radio collars. A total of 74 lions were studied, and only one left the study area, crossing from the San Diego County into Mexico.
The paper estimates between 17 and 27 lions live in the Santa Ana Mountains. With limited breeding partners, those lions are becoming increasingly inbred, threatening their genetic diversity and, ultimately, their survival.
“When landscapes get so fragmented that animals can’t get around, ecosystems unravel,” said Scott Morrison, director of science for The Nature Conservancy in California, and a coauthor of the study. “This study is a wake up call, to avoid developing in ways that create these crises with wildlife.”
Lions were long ago killed off in the eastern U.S., except for a small population of Florida panthers. Those, too, nearly went extinct, until wildlife managers brought in some Texas lions in the 1990s to breed with the Florida animals and increase both the population and the diversity in the gene pool.
Such measures may soon be necessary in Southern California.
“We’re headed in that direction at a steady and maybe accelerating pace. We have chances to attempt to correct the situation, but those will go away,” Vickers said.
The first solution is to make highway crossings safer and more lion-friendly, while blocking lions from the rest of the highway with fences, Vickers said. A good example is the 241 toll road, where the Transportation Corridor Agency is building a fence.
It’s easy to think that such a large, mobile, speedy animal -- the king of the animal kingdom -- would be invincible. But after more than a decade spent studying the animals, Vickers has come to realize how defenseless they really are.
“Mountain lions are an indicator of the power we have to disrupt ecosystems,” Vickers said. “They’re way more vulnerable to us in our day-to-day way we live in Southern California than we think.”
