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  • Los Angeles seems like a surprising home for a large wildlife predator.

  • In fact, LA is one of only two mega cities in the world to have big cats living within the city limits.

  • In LA, the freeways have sliced the mountain lion's habitat into ever-shrinking pieces.

  • And this isolates the populations from each other and causes problems with genetic diversity.

  • All leading to a risk of local extinction in as few as 12 years.

  • But there's hope in saving them by re-linking these lonely lions, even one at a time.

  • If one individual could come across every two or three years,

  • then the genetic makeup of the population would stay fairly stable.

  • Seriously, it only takes the introduction of one new mountain lion to renew genetic health for

  • the local species.

  • But before we get into that, let's explore how mountain lions got into this situation,

  • or more specifically, how we forced them into this situation in the first place.

  • Mountain lions live in a variety of habitats in Southern California.

  • So they are sort of everywhere that there is cover, habitat and deer.

  • We tend to attract some wildlife because of our lawns and our watered areas and our golf courses and things like that.

  • So mountain lions oftentimes live much closer to people than we think.

  • At the lower elevations and the passes and things where highways, have been built,

  • The freeways carve the area up, and they make it such that the animals

  • can't reach from one area to another very easily at all.

  • Either get killed trying to cross, or the highway itself is so noisy,

  • and there's so much light relating to cars that they just can't, they don't want to try it.

  • So, although there are quite a few mountain lions living in the Southern California mountain ranges,

  • and they've been there for thousands of years, the highways are now forcing individual mountain lions

  • to stay where they are, without roaming to new areas as they naturally would.

  • They tend to become inbred, they tend to keep breeding with each other,

  • they don't have new animals coming in to introduce new genetics and so that inbreeding phenomenon,

  • then leads to potentially health problems and susceptibility to disease, reproductive issues.

  • Then the population could go extinct or, in the models, actually did go extinct within that 12 or 13 year period.

  • So, it can happen quickly. If reproduction rates can't keep up with mortality rates.

  • Unfortunately, Dr. Vickers has seen this before.

  • The only mountain lion population we have as an example of what happens with inbreeding

  • is the the Florida Panther, and it was isolated and is isolated in the Everglades

  • and southern Florida.

  • And when its population became low because of all of these same factors, and by low I mean

  • less than 20 individuals in the entire state, they also were tending to just breed with each other.

  • They also started having physical abnormalities changes in their haircoats, kinked tails

  • were one thing that they saw.

  • Cleft palates, physical abnormalities that began to show up because of inbreeding.

  • Female mouth lions were brought in from Texas to breed with that population, and that was a successful

  • introduction of genetic material, and the kitten survival went up, and overall survival went up, and the population

  • has now expanded to between one and 200 animals.

  • In the case of the Southern California mountain lions, conservationists don't want to translocate the animal.

  • But what they really want is to enable the mountain lions to move themselves. And one of the best way to

  • mountain lions for genetic purposes, is to link one wild area to another, with a network

  • of well-disguised movement corridors and road crosses.

  • Wildlife corridors aren't a new idea. They've worked in many other areas with other animals,

  • a wildlife corridor could be anything from a fish ladder, a tunnel for toads, or a highway overpass.

  • Creating passageways across I-15 or improving the existing passageway can certainly allow animals to come

  • across the freeway more freely than they do now.

  • And that could be enough.

  • Overpasses allow the mountain lions to roam freely and mix their gene pools,

  • without ever having to dash across traffic.

  • Currently, two wildlife overpass projects are being proposed - one over the interstate 15

  • in Western Riverside County.

  • And another over the US-101 freeway in Los Angeles.

  • In 2011, one of the lions that successfully made it across without a bridge proves just how helpful mixing

  • individuals can be.

  • That was M86, a male mountain lion that found mates in the Santa Ana mountains, after migrating from a

  • genetically diverse population.

  • He had 11 detected offspring, adding the desperately needed unique genes into the inbred population.

  • So far we've only documented one in 15 years that was successful.

  • M86 was hit by a car and killed the next time he tried to cross.

  • And of course, having these mountain lions so close to humans poses its own challenges, even if the populations

  • are able to mix together.

  • Many locals worry about having large predators so close to their backyards, pets, and children.

  • As top predators they, like wolves and bears, tend to regulate the ecosystem through their prey behavior,

  • with their behavior toward prey.

  • So they reduce deer numbers, versus what would be present if they weren't there.

  • And that can help to downregulate things like vegetation types and browsing levels and things that affect other

  • animals down lower on the food chain.

  • There's been some work that suggests that their role regulating deer populations has not only promoted vegetation

  • balance, but also helps to reduce roadkill and collisions with cars, which endanger humans.

  • Of course, it really helps to preserve large spaces of wild land, before we build on it. Rather than trying to

  • put the pieces back together after the fact

  • I think the role of our populace of people who care about mountain lions is to become more and more

  • active in the conservation of land and the conservation of animals and in whatever way might be

  • suitable to them because local decisions, oftentimes really determine a lot of these habitat issues.

Los Angeles seems like a surprising home for a large wildlife predator.

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Could These Bridges Keep Mountain Lions Safe?

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    林宜悉 posted on 2020/11/24
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