The python the hunters will defeat

Reality TV isn’t generally known for its positive contributions to society. But with this recently published paper on the impacts of invasive Burmese pythons in the Everglades of south Florida, one show seems particularly noteworthy.

National Geographic/OLN’s reality show “Python Hunters” follows three licensed hunters as they wander around the everglades, harvesting invasive reptiles. The show may be light on the science (and a few of the guys are python breeders – what’s with that exactly?), but the show is filled with beautiful animals, exciting chases, massive airboats and backwoods hijinx – just the sort of thing to entertain pre-pubescent boys and those of a like mind. And, the best part, they make an effort to highlight the damaging effects of invasive reptiles on the Everglades. I will watch that.

Especially in the light of this disturbing piece of research: The invasion of the Everglades by the Burmese python has corresponded with a dramatic decrease in mid-sized mammal populations. When I say dramatic, I mean, severe, disastrous, declines. Based on the best available data, between surveys before python invasion (1996-1997) and after (2003 -2011), researchers observed 99.3% fewer raccoons, 98.9% fewer opossums, 87.5% fewer bobcats, and failed to observe any marsh rabbits or foxes. Before python invasion, raccoons and opossums were the most frequently observed mammals. In the 1980s and early 1990s, the Everglades were so lousy with raccoons, and nuisance encounters between the creatures and park visitors so common, that the park management instituted a control program. After pythons, no nuisance encounters have been reported from the southern, most heavily invaded part of Everglades, since 2005. Let that sink in a bit. That these declines were caused by the pythons is supported by the fact that similar surveys in areas newly or uninvaded by the ravenous reptiles tended to have many more observations of these mid-sized mammals.

From Dorcas et al., 2012, PNAS. Abundance of mid-sized mammals from the Everglades National Park, corrected for distance surveyed. Numbers on the x-axis represent change in abundance per 100 km.

I say ‘best available data’ because it’s not what one would hope. As is the case for many threatened ecosystems, researchers lack good baseline data for mammal populations in the Everglades. The data discussed here was obtained from nocturnal road surveys which will bias what animals you will see. But given that they saw them on the road in 1997, they should see them in 2011… unless they’ve been eaten by a python.

Happy hunting, Python Hunters.

Dorcas, M., Willson, J., Reed, R., Snow, R., Rochford, M., Miller, M., Meshaka, W., Andreadis, P., Mazzotti, F., Romagosa, C., & Hart, K. (2012). From the Cover: Severe mammal declines coincide with proliferation of invasive Burmese pythons in Everglades National Park Proceedings of the National Academy of Sciences, 109 (7), 2418-2422 DOI: 10.1073/pnas.1115226109