Wednesday, June 08, 2005

Panther Purity

A cougar, probably of the so- called "Florida panther" race, was hit and killed by a car in northern Florida, far from the usual southern haunts of the subspecies. A story in the St Augustine Record by Peter Guinta-- it requires registration so I'll just quote-- records the good news that the cat's range is expanding but flirts with an odd obsession with genetic purity that crops up in many places, from genetics- obsessed dog standards to the sneers at the restored eastern peregrine as "Cornell chickens".

" "In recent years their numbers have been increasing, and now we've just
lost one," she [ Sarah Owen of the Florida Wildlife Federation]said. "But we're not going to get too excited until we find
out through DNA testing where it's from."

Cunningham said the same thing -- a DNA test is required because there was an experiment in North Florida three years ago that involved releasing
sterilized Texas cougars to find out if a second population of Florida
panthers could survive there. Some of the vasectomies given to those cats
were not effective and they began breeding, he said.

"I couldn't tell the difference at necropsy," he said. "This one did not
have some of the characteristics of the pure, inbred Florida panthers. I
still think it was a Florida panther, but I don't want to rule out that
this could be connected to that project.""

Don't get me wrong-- having the locally- adapted type would always be better-- unless there were none, or the population was dwn to where the remaining animals had problems. But Florida's panthers were in exactly that kind of shape.

"In 1989, data collected from 29 radio-collared panthers indicated that the
population was losing genetic diversity at a rate of three to sevenpercent
yearly. Researchers believed that the gene pool would continue to erode
even if the population stabilized, leading to extinction within 40 years.
Three years later, with the health of the population continuing to
decline, biologists made a controversial decision. In an effort to increase genetic
diversity, wildlife managers introduced several female Texas cougars --
the closest remaining cougar population that had historically shared Florida
panther range -- into the Florida panther population in 1995. Several
hybrid litters have since been produced, and the introduction seems to
have corrected some of the problems experts generally attribute to inbreeding.
Experts are still debating the role of the Texas cougars in panther recovery."

Debating? Why on earth, other than purely pohilosophically? Is it better to lose the panther entirely? Most likely, the environment will shape it back eventually in the direction of the Florida "type"-- though some think that the defining characters of that type may have been signs of inbreeding pathology!

Other questions raised: if the environment is different, does a reintroduced species take on different characteristics? The old eastern anatum peregrine was bigger than its replacement. But if it was because its prey was the big, swift, and abundant passenger pigeon, will the new peregrine ever get as large? Species and ecosystems are fluid entities...

Also: what does this tell us about closed dog studbooks? Hint: nothing good.

I'll soon have some stuff on the passenger pigeon ecosystem up in "Other Works".

Thanks for the tip to Grayal Farr.

1 comment:

Matt Mullenix said...

Interesting to consider position of "The Sixth Extinction"
by Richard Leakey and Roger Lewin (Doubleday, 1995): in short, that "lost" ecosystems can be re-assembled with analog parts, but never recreated and always with unpredictable results. A working system may reform (it seems to 'want' to), but you can't make it what it was.

Question: Does it matter? Working ecosystems are certainly valuable for reasons too many to list, but do any of the component parts have intristic value? Are we less well-off today without mammoths and sabre tooths, etc., in Montana (that's rhetorical Steve: I know you'd say, "YES!"). ...I mean, is the bison/gray wolf/grizzly system that (until recently) replaced them somehow less appropriate than the previous system?

Aren't we all just placeholders for the next age?