Key Largo Woodrat Threatened with Extinction in Florida

Even if a concerted captive-breeding effort is made, it will not be enough to initiate a species rebound for the Key Largo woodrat in Florida. According to University of Florida researchers, the dramatic loss of woodrats in the state cannot be recouped by a captive breeding program.

Since the mid 1980s, the Key Largo woodrat population has fallen from about 6,000 to approximately 500, according to US Fish and Wildlife Services estimates. The drop is worrisome, researchers said, because the woodrats are important to their forest ecosystems. They spread seeds, act as food for snakes and hawks, and provide shelter for other forest creatures by building stick nests.

Using a computer model, researchers simulated what woodrats would do in the wild, how they behave in captivity and what happens when captive rats are released in the wild.

"When we kept looking at the data, what we found was that you really couldn't breed enough woodrats to make it a viable strategy for population recovery," said Robert McCleery, an assistant professor in wildlife ecology and conservation at the University of Florida.

McCleery is co-author of a study on the woodrats appearing in the journal Biological Conservation.

The researchers found that captive woodrats do not exhibit the same breeding habits as their wild counterparts, largely because of dietary restrictions imposed on the captive rats.

Land has been set aside in Florida and dedicated to woodrat conservation, but even with the protection afforded by a conservancy, the woodrat's small population and lack of breeding make it threatened with extinction in Florida.

The International Union for the Conservation of Nature, however, lists the Key Largo woodrat as a species of "least concern," citing a wide US distribution across the Southeast and Midwest.

The Key Largo woodrat is listed as least concern "because it is very widespread, although generally not common, it occurs in many protected areas and its population is not declining fast enough to qualify in a more threatened category," the IUCN reports on its Red List of Threatened Species.

Still, the future may not be bright for the Key Largo woodrat in Florida. Researchers found that captive woodrats released in the wild were much more likely to be eaten by predators than their wild-born counterparts.

"In captivity, they can become habituated to people," McCleery said. Normally, animals should be scared of people, he said. "If you get them to stop responding to scary things, they stop responding to other scary things, like hawks and cats and other natural predators."