Even fast-breeding rabbits can’t withstand Everglades python invasion
Fecund little mammals can’t keep up with voracious reptiles
HOSTILE TAKEOVER Burmese pythons invading the Everglades turn into such active hunters when the weather warms up that they can overwhelm even fast-breeding populations of small mammals.
TODD PIERSON/FLICKR (CC BY-NC-SA 2.0)
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Even breeding like bunnies can’t save some mammals in Everglades National Park from invading Burmese pythons.
When the heat of summer revved up snake activity, the pythons ate up to a fifth of a study population of marsh rabbits each week, researchers report March 18 in Proceedings of the Royal Society B. That rate of predation over the long term is “not even close to sustainable” for the once-abundant rabbit population, says mammal ecologist and study coauthor Robert McCleery of the University of Florida in Gainesville. It’s the best evidence yet — contrary to what a mammal ecologist might predict — that the pythons really could wipe out populations of a famously fast-breeding mammal, he says.
McCleery had been skeptical that pythons by themselves could do so much damage. Marsh rabbits (Sylvilagus palustris) can produce six litters a year of multiple young, he says, and biologists have long expected that in rich habitats, fast-reproducing little animals rebound faster than predators can gobble them.
McCleery and colleagues monitored the fates of 80 marsh rabbits, some introduced into the snakiest locales and some in snake-poor zones. Examining the carcasses revealed mammals as the top predators in python-poor zones. But pythons killed more than two-thirds of the dead rabbits in the high-snake zone. “We’re talking about a total switch of predators,” McCleery says. Pythons, which don’t limit their diet to rabbits, may also be a major cause of dwindling populations of slower-breeding mammals, the study says.
When the heat of summer revved up snake activity, the pythons ate up to a fifth of a study population of marsh rabbits each week, researchers report March 18 in Proceedings of the Royal Society B. That rate of predation over the long term is “not even close to sustainable” for the once-abundant rabbit population, says mammal ecologist and study coauthor Robert McCleery of the University of Florida in Gainesville. It’s the best evidence yet — contrary to what a mammal ecologist might predict — that the pythons really could wipe out populations of a famously fast-breeding mammal, he says.
McCleery had been skeptical that pythons by themselves could do so much damage. Marsh rabbits (Sylvilagus palustris) can produce six litters a year of multiple young, he says, and biologists have long expected that in rich habitats, fast-reproducing little animals rebound faster than predators can gobble them.
McCleery and colleagues monitored the fates of 80 marsh rabbits, some introduced into the snakiest locales and some in snake-poor zones. Examining the carcasses revealed mammals as the top predators in python-poor zones. But pythons killed more than two-thirds of the dead rabbits in the high-snake zone. “We’re talking about a total switch of predators,” McCleery says. Pythons, which don’t limit their diet to rabbits, may also be a major cause of dwindling populations of slower-breeding mammals, the study says.
Citations
R.A. McCleery et al. Marsh rabbit mortalities tie pythons to the precipitous decline of mammals in the everglades. Proceedings of the Royal Society B. Published March 18, 2015. doi: 10/1098/rspb.2015.0120.
Further Reading
M.E. Dorcas et al. Severe mammal declines coincide with proliferation of invasive Burmese pythons in Everglades National Park. Proceedings of the National Academy of Sciences. Published online January 30, 2012. doi: 10.1073/pnas.1115226109.
S. Milius. Like a boomerang, relocated python comes back again. Science News. Vol. 185, May 3, 2014, p. 8.
J. Raloff. Predatory pythons shift Everglades ecology. Science News. Vol. 181, February 25, 2012, p. 5.
J. Raloff. Giant snakes warming to U.S. climes. Science News Online, October 13, 2009.
S. Milius. Like a boomerang, relocated python comes back again. Science News. Vol. 185, May 3, 2014, p. 8.
J. Raloff. Predatory pythons shift Everglades ecology. Science News. Vol. 181, February 25, 2012, p. 5.
J. Raloff. Giant snakes warming to U.S. climes. Science News Online, October 13, 2009.
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