An experiment to increase the genetic diversity of the Florida panther has apparently worked. That's the conclusion of a 10-year study released this week.
The Florida panther was on the ropes by the early 1990's. Development had cut off their contact with other populations, and inbreeding was taking its toll. Many cats couldn't reproduce or even live long enough to reproductive age.
So in 1995, wildlife managers relocated eight female pumas from Texas to south Florida. Since then, their numbers have rebounded from 20 to 30 panthers to between 120 and 240. Madan Oli, a professor of wildlife ecology and conservation in the University of Florida Institute of Food and Agricultural Sciences, is one of the study's authors.
"It was a genetic rescue that led to successful increase in the Florida panther population, reduction in inbreeding and actually documented growth in the population size," Oli said. "We show that panthers with greater genetic diversity are more likely to survive and reproduce than those with less genetic diversity.”
Oli says the cats need to be monitored to watch out for signs that the population might crash again because of too much inbreeding.
He is not aware of any more plans to import more Texas pumas by the Florida Game and Fresh Water Fish commission. But the population remains small and it remains isolated from other groups further west.
"I think personally that ultimately the inbreeding-related problems will return," he said. "But we know that, at the moment, the population is doing very well. Genetic diversity that was brought in through the genetic rescue experiment still remains in the population. So at the moment, I really do not see any immediate need for additional females to be introduced from Texas or elsewhere."
The project mimicked the genetic exchange between panthers and pumas from Texas that once occurred naturally, before panthers became isolated in south Florida. If the released Texas females mated with male Florida panthers, their offspring should exhibit more genetic variation, which in theory might improve their survival and reproductive rates.
But at the time, that theory had not been tested in a wild population of large carnivores, and scientists weren’t sure it would work.
“There were some concerns expressed that breeding Florida panthers with Texas pumas could have a negative impact on the Florida panther population,” said Dave Onorato, a research scientist with FWC and one of the co-authors of the study.
Some people have said since the Texas pumas were introduced, there's no such thing anymore as a Florida panther. Oli says there are very few genetic differences between the two groups. So scientsts had little choice if they wanted to save the species.
"So the alternative clearly was having no panthers versus having some panthers with Texas genes," he said.
They found that introducing five Texas pumas every 20 years would help prevent inbreeding and reduce the risk of extinction.
The authors note that even though genetic management is an important conversation tool, conserving panther habitat is critical to their survival. Most of the panthers live in southwest Florida, below the Caloosahatchee River.