Invasive pythons wiping out Everglades species
A slithering, surging population of Burmese pythons in the Florida Everglades, many of them escaped or abandoned pets, appears to be eating its way through many animals native to the sensitive wetlands, according to a study.
Researchers writing in the Proceedings of the National Academy of
Science found what they characterized as “severe declines” in the population of small and mid-sized native mammals in the huge national park and linked it to the growing presence of Burmese pythons.
The study, the first to document the ecological effects of the invasive species on the Everglades, was released on Monday.
The giant constrictors, which commonly grow to be more than four metres long, are not native to the Everglades, the largest subtropical wilderness in the United States and home to a number of rare and endangered species.
But they are popular and legal pets in the United States. Some escape. Some are released by owners who panic as their baby snakes quickly mature into giant, dangerous adults.
The pythons have been what scientists call “an established invasive species” in the Everglades, predators that occasionally prey on the American alligator and the Florida panther.
The python’s impact has been dramatic on the population of smaller mammals, including racoons, opossums, marsh and cottontail rabbits, foxes and bobcats, which has dropped precipitously in recent years, researchers said.
In fact, in southern end of the Everglades, where the pythons have been established the longest, researchers said raccoon sightings have dropped 99.3 per cent, while sightings of opossum have dropped 98.9 per cent and bobcat sightings have fallen 87.5 per cent.
Researchers did not detect a single rabbit — dead or alive — once inside the park during the nine-year study. Nuisance calls involving raccoons used to light up the park service’s switchboard, researchers said. Since 2005, not a single park visitor has called to report a nuisance raccoon, according to the study.
A number of water birds — grebes, herons and the federally endangered wood stork — also appear to be falling to python predation, the researchers said.
Experts at the U.S. Geological Survey said the odds of eradicating the pythons now are “very low.”