New Study Contradicts USGS Python Climate Projections

[ER12]

New Study Contradicts USGS Python Climate Projections; growing evidence suggest struggling Florida pythons won’t expand north

A new study published in Integrative Zoology examines the impacts of cold temperatures on Burmese pythons. The study, ‘Environmental, physiology and behavior limit the range expansion of invasive Burmese pythons in southeastern USA’ (Jacobson et al. 2012), was prompted by a USGS climate prediction (Reed Rodda 2008) claiming feral Burmese pythons in the Everglades could expand as far north as the southern third of the US. Since the USGS report was published, there have been three cold weather python studies published in scientific journals that contradict USGS claims of the python’s ability to tolerate temperate climates outside of southernmost Florida (Avery et al. 2010; Dorcas et al. 2011; Mazzotti et al. 2011). Now the new study, a collaborative work between University of Florida, USDA Wildlife Services and python experts, identifies the fundamental flaw in the USGS study and details why it is unlikely feral pythons can survive north of the Everglades.

The USGS study sought to create a climate match comparing the python’s native range to a potential range here in the US. The methodology was to use median temperatures from the native range of the python, and overlay that data to create a climate matching map across the southern third of the US. The flaw in the USGS work revealed by Jacobson et al revolves around the erroneous idea that median temperatures are an accurate way to determine range. They are not. Temperature extremes, especially the low temperatures reached in a given climate are much more important. As tropical species, pythons are morphologically, physiologically and behaviorally ill-equipped to tolerate low temperatures commonly reached north of the Everglades during the winter. In other words, pythons can barely tolerate cold temperatures in south Florida let alone central and north Florida, or outside of the state.

The National Geographic Society’s Resident Herpetologist, Dr. Brady Barr, has stated, “Climate data reveal that temperatures found in southern Florida simply are not conducive to the long term survival of large tropical snakes. When it gets cold, these snakes die”. Dr. Barr goes on to say, “Feral Hogs are a bigger problem for the Everglades than pythons. The press has sensationalized this story to the point that people think the sky is falling. Hopefully comprehensive research such as Jacobson et al. will put an end to the hysteria.”

The US House Natural Resources Committee, Subcommittee on Fisheries, Wildlife, Oceans and Insular Affairs will hold a hearing on H.R. 511 on Thursday November 29th. The bill known as the ‘Python Ban’ seeks to add nine constricting snakes to the Injurious Wildlife list of the Lacey Act. The Subcommittee Chair is Representative John Flemming (R-LA). The hearing will be held in the Longworth House Office Building at 10:00 AM. The United States Association of Reptile Keepers opposes the addition of any constricting snakes to the Injurious Wildlife list.
http://usark.org/?p=1494

[Don]

Good post and it reinforces what most reptile enthusiasts already know. The problem is that our politicians do not care about facts. They just react to fear. Hopefully, we can get the hysteria to calm down and talk about this in a non emotional fact based conversation. If that ever happens, then we have a chance in changing some minds.

[3skulls]

They react to money..

[ER12]

There are several exotic snake species that have become a problem in the Everglades. But for wildlife managers, the biggest headache is the Burmese python.

Earlier this year, researchers with the U.S. Geological Survey captured the largest Burmese python yet in Everglades National Park. Three USGS staffers had to wrestle the snake out of a plastic crate to measure it. The snake was a 17-foot-7-inch female carrying 87 eggs.

Wildlife managers are working to get a handle on the problem of exotic snakes in South Florida; but the snakes have already made a big impact.

One study suggests that in Everglades National Park, pythons have reduced the population of raccoons, opossums, deer and other mammal species by 90 percent.

To help combat the problem, the federal government earlier this year banned the importation and sale of Burmese pythons and three other exotic snake species.

One reason was fears that pythons might spread to other states. A study several years ago by the USGS found pythons could potentially spread up the East Coast and west to California.
Related NPR Stories
Florida Museum of Natural History researchers at work on the record-long Burmese python.
The Two-Way

Florida's Biggest Python So Far Measured 17 Feet, 7 Inches; Had 87 Eggs
Nonnative pythons, like this one, are invading the Florida Everglades. As a top predator, the snakes have crippled the populations of rabbits, raccoons and other animals.
Animals

Invasive Pythons Put Squeeze On Everglades' Animals

But Elliott Jacobson, a professor emeritus of zoological medicine at the University of Florida, says a new study questions how far beyond South Florida pythons could spread.

"These maps give a very false sense of distribution," Jacobson says.

In a study published in the journal Integrative Zoology, Jacobson and other researchers looked closely at the low and high temperatures found along the East Coast in the python's projected habitat range. Freezing temperatures are deadly for pythons. And Jacobson says pythons have trouble eating and digesting food at temperatures below 60 degrees.

"The bottom-line conclusion was the number of freezing days in the winter is going to limit the ability of this animal to spread beyond extreme South Florida," he says.

Jacobson says this new information shows the federal government overreacted when it imposed a national ban on a species that's a problem just in Florida.

And some other well-known scientists are also speaking out against the python ban.

"The press has made this a big deal. The sky is falling — I call it the Chicken Little syndrome — when indeed it isn't," says Brady Barr, the resident herpetologist with the National Geographic Society.

Barr says the new study shows something he and other researchers have maintained for some time — that Burmese pythons can't spread far beyond Florida's three southern-most counties. Barr says that's because, unlike native snakes, pythons can't tolerate cold, and they lack the instinct to hibernate.

"They don't have the innate ability to find hibernacula, to find places to hide or to be warm. They don't know how to do that," Barr says.

That question — whether snakes from tropical climes, like pythons, may take measures to adapt to the cold — is one that divides herpetologists. Gordon Rodda, now retired from the USGS, helped write the report showing that pythons could potentially spread throughout the Southeast U.S. He says there's nothing in this new report to change his thinking, including its doubts about whether pythons may learn to adapt to cold.

"We know that Burmese pythons in the more high altitude portions of their range do in fact hibernate. The question then is: How do they acquire that behavior to do so?" Rodda says.

This is a question that may come up in Congress later this week. A House subcommittee is holding a hearing on whether to extend the ban on Burmese pythons to other exotic snake species.
http://www.npr.org/2012/11/26/165941...est-of-the-u-s

[Don]

Wild pigs and feral cats - lets outlaw those before we worry about burms invading half the country. Hysteria continues to trump science. Such a shame.

[kitedemon]

Elliott Jacobson: three cheers!


One of the top IBD researchers too. I am so glad I made a donation to his lab now!