Monday, February 6, 2012

Proliferating pythons

An ecological disaster has occurred in the Florida Everglades no thanks to an invasive species - the Burmese python - which is a great swimmer and ideally suited for its adopted habitat. Escaped from breeders during Hurricane Andrew in 1992 and released by irresponsible pet owners, the snakes quickly assumed their place as the apex predator, even taking on alligators. The smaller game is no match at all. In an earlier post, I reproduced a graphic showing how many animals a growing python would need to eat to reach a length of 13'. With tens of thousands of pythons now populating the Everglades, it is no wonder that the native wildlife is suffering. But it is an eye-opener that several species are all but wiped out. In a just-published study in the Proceedings of the National Academy of Sciences (read it here), lead author Michael E. Dorcas of the Biology Dept. at Davidson College and his coauthors reveal that in the past 15 years, sightings of raccoons have decreased by 99.3%, opossums by 98.9%, white-tailed dear by 94%, and bobcats by 87.5%. Rabbits (marsh and cottontail) and foxes were not seen at all. Equally at risk are dozens of other species including coyotes, Florida panthers, egrets, rails, limpkins, white ibis, grebes, herons, and endangered Key Largo woodrats and wood storks. "Pythons are wreaking havoc on one of America's most beautiful, treasured and naturally bountiful ecosystems. Right now, the only hope to help halt further python invasion into new areas is swift, decisive and deliberate human action," says U.S. Geological Survey director Marcia McNutt. But despite official raids and public hunting permits, the pythons are reproducing at a far greater rate than they can be captured and killed by humans (who have only been able to remove 1,300 since 2000). What I thought at first were consumed carcasses in the dissected 117lb, 16' female python shown above are actually 59 large fertile oviductal eggs each containing a viable embryo. Research by University of Florida wildlife ecology associate professor Frank Mazzotti (read it here) indicates that only prolonged cold snaps are enough to make a dent in the python population - or at least slow them down enough so that they can be hunted more effectively. And the best things to find in the traps are snakes full of eggs: “The highest priority in controlling the expansion of Burmese pythons is removing reproducing females. That’s the Holy Grail,” says Mazzotti.

1st image) a Burmese python captured in the Florida Everglades in a photo by Skip Snow/Everglades National Park, 2nd image) a Burmese python caught and killed by a South Florida Water Management District employee in a photo by UF’s Fort Lauderdale Research and Education Center.

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