Some time back, in a post entitled Islands of Wolves, Rats, Lions and Dogs, I detailed why population bottle necks are not quite as simple an issue as some would have you believe, as a lot depends on the length of an animal's life, the number of progeny in a year, the length of time before first birth, life-span, mating habits, time, total population numbers, and the level of genetic diversity in the establishing or remaining population.
In the real world, population bottlenecks are not always quite as big a problem as some people imagine, nor are they quite as easy to correct as some people hope. If that sounds like two statements in direct opposition, then you have grasped a core message of this post, which is that not all animal populations are the same, that few real-world cases line up squarely with simple theory, and that there are multiple facets to both genetic isolation and genetic rescue.
One of the example animals given was the Florida Mountain Lion or Florida Panther.
Now imagine a large population of lions that has been reduced by hunting to just 30 individuals living on an isolated isthmus 200 square miles in size. The population is so isolated that the coefficients of inbreeding within the lion population begin to rise, and a rise of infecundity and an increase in genetic defect is feared. The good news, however, is that this isthmus is not at carrying capacity for lion, and so eight completely unrelated female lions are imported from another country more than 1,000 miles away -- a 25% population boost representing a massive increase in genetic diversity. What happens? A rather significant improvement in species health and fecundity seems to occur, and the lions begin colonizing more space on the isthmus.
Since I wrote that post, a little over three and a half years ago, there has been a population explosion of Mountain Lions in Florida. National Public Radio reports:
Now, nearly 200 range throughout southwest Florida. And some officials, ranchers and hunters in the state say that may be about enough...
Creating a travel corridor for panthers and other wildlife has become increasingly important as the big cat's population has grown in southwest Florida.
"Because their ranges are fairly large," says Wendy Matthews, with the Nature Conservancy, "they need to move north in order to continue having a healthy population in terms of genetics and then also being able to have sufficient game to eat and feed their kittens with."
Florida officials estimate there are now at least 180 Florida panthers living on millions of acres of public and private land in Florida. But after decades of protecting the panther and working to expand its habitat, state wildlife officials now say they want to adopt a new policy toward the endangered species.
Under a federal recovery plan for the panther, it can't be taken off the endangered species list until three populations of 240 animals or more are established in Florida or other Southeastern states.
Liesa Priddy, a member of the Florida Fish and Wildlife Conservation Commission and a ranch owner, believes those goals may be unrealistic.
"We're at the point where we're probably pushing the 240 animals in this primary, first range for panthers," she says. "And where does the second population go? Because it takes a lot of contiguous land to support a panther population."
Of course, the bottom line is the bottom line. Florida is a popular retirement destination and the Baby Boom generation is retiring in droves. Unable to afford expensive homes on the coast, more and more are opting for land in Florida's interior. This is a classic battle between greed and need, people and wildlife, the interlopers and the original residents:
But panthers are just one part of a much larger dispute playing out in Florida: one about land use and the future of millions of undeveloped acres in the state. After decades of development along the coasts, builders and retirees are increasingly looking to new communities in Florida's interior, including areas west of Lake Okeechobee where panthers are becoming common.
Paul Carlisle, an administrator from Glades County, says more than one-third of the land there is already under conservation easements. Setting aside more land for panthers, he says, would hurt the county's economy. The panther, Carlisle noted to the commission, used to range not just in Florida, but throughout the Southeast, from Texas to North Carolina.
Not said in the NPR piece is that there is no such thing as a Florida Panther. It's just a Mountain Lion, same as can be found in other parts of the nation. This is "subspecies" fiction designed to protect habitat; a worthy goal based on bad science.
If Florida has "extra" Mountain Lions, why not move a few of them north into Georgia, North Carolina, Virginia, Kentucky, and upstate New York?
There is more than enough wild land out there to support a sizable Lion population. There is no reason in the world to bottle up "the Florida Panther" in Florida, since there was never such a thing as the Florida Panther. Mountain Lions are Mountain Lions.
The US once had a large Mountain Lion population that stretched from California to Virginia, from Texas to Minnesota, and from Florida to Maine.
Let's restore that population -- or as much of it as we possibly can. Yes, there will be a few problems with livestock and pets and people, and the occasional Lion will have to be relocated or shot. But Lions breed relatively fast and can be managed on the land. Let us return what land we can to one of America's top end predators,