Florida conservationists cold toward iguanas & pythons in record chill

From ANIMAL PEOPLE, March 2010:

MIAMI–Conservationists rushed to help endangered sea turtles
and manatees during one of the coldest winters on record in Florida,
but many vocally hoped that the January 2010 cold snaps would
extirpate non-native iguanas and pythons.
“Anecdotally, we might have lost maybe half of the pythons,”
Florida Fish and Wildlife Conservation Commission exotic species
coordinator Scott Hardin told David Fleshler and Lisa J. Huriash of
the South Florida Sun-Sentinel in mid-February, after several weeks
of doing habitat assessment.

Hardin also estimated “more than 50 percent fatality on green iguanas.”
The cold weather also killed thousands of Mayan cichlids,
walking catfish, and spotfin spiny eels, among other tropical
colonists of Florida habitat.
The python deaths revitalized opposition to U.S. Senate Bill
373, which seeks to ban the import of pythons into the U.S.
Contrary to a U.S. Fish & Wildlife Service estimate that pythons
could potentially colonize most of the South, “Pythons can’t exist
more than a short period of time north of Lake Okeechobee,” U.S.
Associ-ation of Reptile Keepers president Andrew Wyatt told Fleshler
and Huriash.
But the 50% mortality rate among pythons and other immigrant
species was well below the minimum of 70% mortality that would be
necessary to suppress the numbers of any of them for very long.
“Green iguanas have been thudding to the ground at Bill Baggs
Cape Florida State Park in Key Biscayne and other leafy areas,”
reported Robert Samuels of the Miami Herald at the depth of the
freeze. “When temperatures plunge into the 30s, iguanas become
catatonic,” Samuels wrote, “falling from trees in a state of
suspended animation. When the weather warms, they reanimate,
sometimes worse for wear.”
Dogs who gnawed dead reptiles were also among the victims.
Veterinarians throughout South Florida were baffled near the end of
January when they began seeing unusually large number of dogs coming
to them with creeping paralysis, starting in the hindquarters,
moving forward, and in extreme cases causing the dogs to suffocate.
Intubation saved some, but “In at least two such South Florida
cases, dogs who could not breathe were euthanized,” reported Elinor
J. Brecher of the Miami Herald.
Veterinary neurologist Brian Roberts of Veterinary
Specialists of South Florida in Cooper City eventually recognized the
symptoms as possible botulism poisoning–rare in mammals, but
treatable with an antitoxin if promptly recognized. Roberts alerted
fellow vets. The International Society for Infectious Diseases
amplified the warming, but appealed for confirmation of the
unprecedented finding.
Botulism is caused by an anaerobic bacterium, most notorious
for contaminating canned food that has been inadequately cooked
before canning. In nature botulism most often attacks waterfowl,
but may be found in the remains of other species.
University of Florida wildlife scientist Frank Mazzotti in an
early February assessment of field reports noted “at least 70 dead
crocodiles, 77 manatee carcasses, and perhaps the biggest fish kill
in modern Florida history,” recounted Curtis Morgan of the Miami
Herald. The manatee deaths from cold exceeded by 21 the then-record
losses from a 2009 cold snap. Morgan called the crocodile deaths “a
significant hit to a species removed from the endangered list only
three years ago.”
“What we witnessed was a major ecological disturbance equal
to a fire or a hurricane,'” Mazzotti said. But Mazzotti noted that
iguanas in particular appear to have increased their resiliance in
response to previous Florida cold snaps. “Although the population
gets knocked back a bit, iguanas don’t seem to be disappearing,” he
told Morgan.
Even shallow water corals were reportedly afflicted in the
Florida Keys, from Key Largo through the Dry Tortugas beyond Key
West. “It’s ecosystem-wide mortality,” said Nature Conservancy
marine science coordinator Meaghan Johnson.
“Star and brain corals that can take hundreds of years to
grow are white and lifeless as bones. Dead sea turtles, eels and
parrotfish litter the bottom,” wrote Morgan.
About 4,300 of more than 5,000 hypothermic sea turtles who
were found still alive were successfully treated at rescue centers
around the Florida coast, including at the Gumbo Limbo Nature Center
in Boca Raton, opened just a few days before the crisis began.
Gumbo Limbo staff and volunteers from the Loggerhead
Marinelife Center in Juno Beach, Walt Disney’s Wild Animal Kingdom,
and the Georgia Sea Turtle Center took the opportunity to remove
fibropapilloma tumors from 35 of the 170 sea turtles who were treated
at Gumbo Limbo, reported Palm Beach Post staff writer Samantha
Frank. Left untreated, the tumors can kill sea turtles.
The January cold hurt sea turtles as far west as Corpus
Christi, Texas. Texas rescuers found about 425 hypothermic sea
turtles, but Sea Turtle Inc. of South Padre Island, the Animal
Rehabilitation Keep, and the Texas State Aquarium among them were
only able to save about 100, Lynn Brezosky of the San Antonio
Express-News reported.
Most of the Florida and Texas turtle victims were green sea
turtles, but two rare Kemp’s Ridley sea turtles washed ashore in
Alabama. One was found dead. The other recovered and was returned
to the sea on January 22, reported Ben Raines of the Mobile
Press-Register.
Contrasting with the conservationist concern for the
endangered and threatened species was the glee of many, including on
the Miami Herald staff, at the deaths of pythons.
More than 1,000 Burmese pythons have been found in the
Everglades in recent years. Python trappers working on behalf of the
Florida Fish & Wildlife Conservation Commission in January 2010 also
captured three African rock pythons and an anaconda, believed to be
the first giant snake of South American descent to be found in
Florida. Nile monitors have been found in the past.
All are believed to have descended from released or escaped
pets. Florida did not regulate the reptile trade until 2008.
Pythons in their native habitat usually respond to cold
weather by burrowing into the deepest, dryest places they can find
and going into torpor. Frezing rain may have thwarted that strategy
in Florida.
Whether the presence in Florida of either iguanas or pythons
should be regarded as an ecological problem is a matter of debate.
Iguanas inhabit most of the Carrib-ean region, and Florida
is within their normal climatic range.
Pythons–and anacondas–evolved, long before mammals
existed, as predators of crocodilians. The constricting method of
killing used by pythons and anacondas takes advantage of the “death
roll” used by crocodilians to drown prey and fend of attackers.
Historically, giant constricting snakes occur wherever
crocodilians–such as American alligators and crocodiles–are
abundant. The U.S. until recently was an exception, lacking giant
constrictors since the Ice Ages, but as the alligator population
native from Florida to Texas expands northward and westward, with no
other major predators except humans, pythons and anacondas enjoy a
growing habitat niche, from which extirpating them may not be
possible.
Captive pythons have killed humans, including a two-year-old
girl in Sumter County, Florida, in July 2009, but wild pythons so
rarely harm humans that in much of India and Southeast Asia the
presence of a python is believed to indicate a safe place to wash
clothing and bathe, as the python affords protection against
leopards and crocodiles.