Back from the brink

A new study conducted by researchers at the University of Florida and the Florida Fish and Wildlife Conservation Commission presents positive developments in the overall health and population of the endangered Florida panther.

The Florida panther population, once as low as 20 to 30 individuals, has rebounded to a range of 120 to 230 panthers following a successful crossbreeding experiment with Texas pumas that began in 1995. Twenty-four years later, panthers bred from the female pumas from Texas and the male panthers from Florida were found to have better chances of survival and reproductive success than their predecessors, which suffered from inbreeding.

As UF Wildlife and Ecology Conservation professor and study co-author Madan Oli put it, “We want happier and healthier panthers.” And the results of the study, titled “Dynamics, Persistence and Genetic Management of the Endangered Florida Panther Population,” indicate just that.

The Florida panther was officially classified as endangered by the Endangered Species Act in 1973 — the year it was passed — according to the National Wildlife Federation. Their population dwindled to as low as 20 to 30 panthers due to hunting and habitat loss which restricted them to South Florida, where they once roamed the entire state, including Alachua County and Marion County. This population decrease led to a limited gene pool which increased the risk of heart defects and infertility, among other maladies, researchers found.

Reinforcements to Florida’s panther population arrived in 1995 in the form of eight female pumas from Texas in an effort by wildlife managers to increase genetic diversity. The Florida panther’s substantial population rebound dispelled researchers’ fears that the infusion of pumas could potentially have an adverse impact on an already endangered population.

There once was a time where this interaction between the pumas and panthers, which are of the same species, occurred organically, before the Florida panther’s isolation in the peninsula.

“What the managers did was to kind of help the same kind of connection that used to happen naturally,” Oli said.

Texas pumas and Florida Panthers are both subspecies of cougar.

UF joined the Florida Fish and Wildlife Commision’s panther study 10 years ago. Oli said the FWC has been focused on wildlife management, while his role was to bring science into that management.

“It’s a good thing to collect data but ultimately you have to analyze the data to see what the numbers mean, and that’s where we come in,” Oli said.

The purpose of the crossbreeding was not explicitly aimed at increasing the panther population, Oli said. Rather, that increase was a result of successfully spawning healthier panthers unaffected by inbreeding.

Still, he does not expect the panther population to continue to grow due to habitat limits. But the numbers appear to have stabilized, albeit still within the parameters of being classified as endangered.

Oli added that the estimated population is such a wide range because, “It’s really hard to count panthers.” But the baseline estimate of 120 means that at least that many have been documented, and researchers have reason to believe there could be at least 100 more that have eluded documentation.

The current plan is to reintroduce five Texas pumas every 20 years to the Florida panther population to continue combating the negative effects of inbreeding. Oli said the number of pumas being brought in is relatively small to prevent their genes dominating those of the panthers.

Normally, the effects of bringing in new genes to address inbreeding population declines rapidly, Oli said. But the benefits of the introduction of the Texas pumas in 1995 are still prominent today, leading Oli to be optimistic about its application.

“I think it raises hope for a lot of endangered species that occur in small numbers,” he said.

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