Featured Research

from universities, journals, and other organizations

Severe python damage to Florida's native Everglades animals documented in new study

Date:
January 30, 2012
Source:
Davidson College
Summary:
Precipitous declines in formerly common mammals in Everglades National Park in Florida have been linked to the presence of invasive Burmese pythons, according to new research. The study, the first to document the ecological impacts of this invasive species, strongly supports that animal communities in the 1.5-million-acre park have been markedly altered by the introduction of pythons within 11 years of their establishment as an invasive species. Mid-sized mammals are the most dramatically affected, but some Everglades pythons are as large as 16 feet long, and their prey have included animals as large as deer and alligators.

Mike Dorcas (r) and students handle a large python brought to campus in 2006. Dorcas implanted this snake and others with radio tracking devices to learn their habits and movements.
Credit: Image courtesy of Davidson College

Precipitous declines in formerly common mammals in Everglades National Park in Florida have been linked to the presence of invasive Burmese pythons, according to a study by Michael Dorcas, an associate professor of biology at Davidson College, and colleagues. The research is published in the Proceedings of the National Academy of Sciences.

The study, the first to document the ecological impacts of this invasive species, strongly supports that animal communities in the 1.5-million-acre park have been markedly altered by the introduction of pythons within 11 years of their establishment as an invasive species. Mid-sized mammals are the most dramatically affected, but some Everglades pythons are as large as 16 feet long, and their prey have included animals as large as deer and alligators.

"The magnitude of these declines underscores the apparent incredible density of pythons in Everglades National Park and justifies the argument for more intensive investigation into their ecological effects, as well as the development of effective control methods," said Dorcas, lead author of the study and author of the 2010 book Invasive Pythons in the United States.

He continued, "Such severe declines in easily seen mammals bode poorly for the many species of conservation concern that are more difficult to sample but that may also be vulnerable to python predation."

The most severe declines, including a nearly complete disappearance of raccoons, rabbits and opossums, have occurred in the remote southernmost regions of the park, where pythons have been established the longest. In this area, populations of raccoons dropped 99.3 percent, opossums 98.9 percent and bobcats 87.5 percent. Marsh and cottontail rabbits, as well as foxes, were not seen at all.

The researchers collected their information via repeated systematic night-time road surveys within the park, counting both live and road-killed animals. Over the period of the study, researchers traveled a total of nearly 39,000 miles from 2003 to 2011 and compared their findings with similar surveys conducted in 1996 and 1997 along the same roadways before pythons were recognized as established in Everglades National Park.

The authors also conducted surveys in ecologically similar areas north of the park where pythons have not yet been discovered. In those areas, mammal abundances were similar to those in the park before pythons proliferated. At sites where pythons have only recently been documented, however, mammal populations were reduced, though not to the dramatic extent observed within the park where pythons are well established.

"Pythons are wreaking havoc on one of America's most beautiful, treasured and naturally bountiful ecosystems," said U.S. Geological Survey director Marcia McNutt. "Right now, the only hope to help halt further python invasion into new areas is swift, decisive and deliberate human action."

The authors suggested that one reason for such dramatic declines in such a short time is that these prey species are "naοve" -- that is, they not used to being preyed upon by pythons since such large snakes have not previously existed in that ecosystem.

"It took 30 years for the brown treesnake to be implicated in the nearly complete disappearance of mammals and birds on Guam; it has apparently taken only 11 years since pythons were recognized as being established in the Everglades for researchers to implicate pythons in the same kind of severe mammal declines," said Robert Reed, a USGS scientist and co-author of the paper. "It is possible that other mammal species, including at-risk ones, have declined as well because of python predation, but at this time, the status of those species is unknown."

Another coauthor of the study was John Willson '02, a research scientist at Virginia Tech University who has worked with Dorcas on several studies, and co-authored the book Invasive Pythons in the United States.

Willson commented, "Our research adds to the increasing evidence that predators, whether native or exotic, exert major influence on the structure of animal communities. The effects of declining mammal populations on the overall Everglades ecosystem, which extends well beyond the national park boundaries, are likely profound, but are probably complex and difficult to predict. Studies examining such effects are sorely needed to more fully understand the impacts pythons are having on one of our most unique and valued national parks."

On January 23 the U.S. Fish and Wildlife Service published a rule in the Federal Register that will ban the importation and interstate transportation of four non-native constrictor snakes that threaten the Everglades, including the Burmese python. These snakes are being listed as injurious species under the Lacey Act.

In addition to Dorcas and Willson, authors of the study are Robert N. Reed, USGS; Ray W. Snow, NPS; Michael R. Rochford, University of Florida; Melissa A. Miller, Auburn University; Walter E. Meshaka, Jr., State Museum of Pennsylvania; Paul T. Andreadis, Denison University; Frank J. Mazzotti, University of Florida; Christina M. Romagosa, Auburn University; and Kristen M. Hart, USGS.


Story Source:

The above story is based on materials provided by Davidson College. Note: Materials may be edited for content and length.


Journal Reference:

  1. Michael E. Dorcas, John D. Willson, Robert N. Reed, Ray W. Snow, Michael R. Rochford, Melissa A. Miller, Walter E. Meshaka, Jr., Paul T. Andreadis, Frank J. Mazzotti, Christina M. Romagosa, and Kristen M. Hart. Severe mammal declines coincide with proliferation of invasive Burmese pythons in Everglades National Park. Proceedings of the National Academy of Sciences, 2012; DOI: 10.1073/pnas.1115226109

Cite This Page:

Davidson College. "Severe python damage to Florida's native Everglades animals documented in new study." ScienceDaily. ScienceDaily, 30 January 2012. <www.sciencedaily.com/releases/2012/01/120130193241.htm>.
Davidson College. (2012, January 30). Severe python damage to Florida's native Everglades animals documented in new study. ScienceDaily. Retrieved July 31, 2014 from www.sciencedaily.com/releases/2012/01/120130193241.htm
Davidson College. "Severe python damage to Florida's native Everglades animals documented in new study." ScienceDaily. www.sciencedaily.com/releases/2012/01/120130193241.htm (accessed July 31, 2014).

Share This




More Plants & Animals News

Thursday, July 31, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Visitors Feel Part of the Pack at Wolf Preserve

Visitors Feel Part of the Pack at Wolf Preserve

AP (July 31, 2014) — Seacrest Wolf Preserve on the northern Florida panhandle allows more than 10,000 visitors each year to get up close and personal with Arctic and British Columbian Wolves. (July 31) Video provided by AP
Powered by NewsLook.com
Florida Panther Rebound Upsets Ranchers

Florida Panther Rebound Upsets Ranchers

AP (July 31, 2014) — With Florida's panther population rebounding, some ranchers complain the protected predators are once again killing their calves. (July 31) Video provided by AP
Powered by NewsLook.com
Dangerous Bacteria Kills One in Florida

Dangerous Bacteria Kills One in Florida

AP (July 31, 2014) — Sarasota County, Florida health officials have issued a warning against eating raw oysters and exposing open wounds to coastal and inland waters after a dangerous bacteria killed one person and made another sick. (July 31) Video provided by AP
Powered by NewsLook.com
Raw: Thousands Flocking to German Crop Circle

Raw: Thousands Flocking to German Crop Circle

AP (July 30, 2014) — Thousands of people are trekking to a Bavarian farmer's field to check out a mysterious set of crop circles. (July 30) Video provided by AP
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
 
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:  

Breaking News:

More Coverage


Severe Declines in Everglades Mammals Linked to Invasive Pythons, Researchers Find

Jan. 31, 2012 — New research links precipitous declines in formerly common mammals in Everglades National Park to the presence of invasive Burmese ... read more
from the past week

In Other News

... from NewsDaily.com

Science News

Health News

    Environment News

    Technology News



      Save/Print:
      Share:  

      Free Subscriptions


      Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

      Get Social & Mobile


      Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

      Have Feedback?


      Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
      Mobile iPhone Android Web
      Follow Facebook Twitter Google+
      Subscribe RSS Feeds Email Newsletters
      Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins