Burmese Pythons Pose Little Risk to People in Everglades plus 1 more

[USGS Newsroom <oc_web@xxxxxxxx>]

Title: USGS Newsroom

Burmese Pythons Pose Little Risk to People in Everglades plus 1 more

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Burmese Pythons Pose Little Risk to People in Everglades

Posted: 27 Feb 2014 10:30 AM PST

Contact Information:

Bob  Reed ( Phone: 970-226-9230 ); Christian Quintero ( Phone: 813-498-5019 );

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Reporters: Photos, b-roll and FAQs are available online.

EVERGLADES NATIONAL PARK, Fla. -- The estimated tens of thousands of Burmese pythons now populating the Everglades present a low risk to people in the park, according to a new assessment by U.S. Geological Survey and National Park Service scientists.

The human risk assessment looked at five incidents that involved humans and Burmese pythons over a 10-year period in Everglades National Park. All five incidents involved pythons striking at biologists who were conducting research in flooded wetlands.

"Visitor and staff safety is always our highest priority at Everglades National Park," said Superintendent Dan Kimball. "Everglades, as many other national parks, draws many thousands of visitors for the opportunity to view the wildlife that live here in a natural setting.  Our guidance to visitors with respect to Burmese pythons is the same as for our native wildlife -- please maintain a safe distance and don't harass the wildlife.  With respect to controlling Burmese pythons, we are working diligently with our state, federal, tribal, and local partners to manage this invasive species and educate the public on the importance of not letting invasive species loose in the wild."

Although there have been numerous bites to people provoking Burmese pythons by attempting to capture or kill the snakes, this study examined only unprovoked strikes directed at people.

"The strikes did not appear to be defensive, but were more likely were associated with aborted feeding behavior," said USGS wildlife biologist and herpetologist Bob Reed, the lead author of the study. "Pythons usually direct defensive strikes at the front of a person, not from the side or rear, as all of these strikes were. Additionally, Burmese pythons rely on being secretive and evading detection as their primary means of avoiding interactions with people, and typically don’t strike until provoked."

The biologists did not detect any of the snakes before the strikes occurred, making it even more likely that the attacks were related to feeding and not defense, Reed noted. Two of the attacks resulted in very minor injuries from the pythons’ teeth and none involved constriction.

Reed and his co-author, retired Everglades National Park scientist Skip Snow, consider the attacks as cases of mistaken identity. In four of five cases the python was small compared to the size of the person, which resulted in the snake likely aborting the attack upon realizing the large size of its prey. Aborting strikes before actual bites with the possible prey indicates that pythons may be able to assess the size of the prey mid-strike and adjust accordingly, the study said.

Although the pythons’ threat to people is low, previous studies have shown that this invasive snake species is having a negative effect on many of the native mammals in the South Florida Everglades. One study suggests the population of raccoons, opossums, and bobcats have declined significantly in the regions of Everglades National Park where pythons have been established the longest.

More than one million people visit Everglades National Park every year, often traveling along hiking and canoeing trails where Burmese pythons have been spotted or captured. Despite this close interaction, the study noted that none of the reported incidents involved a park visitor.  All of the incidents were directed at biologists moving through remote and flooded areas of the park

"As people wade through shallow water, they produce ripples that move ahead of them, and these pressure waves may be detectable to a motionless snake in ambush posture," said Reed. "We speculate that detecting these changes in water pressure may alert a python that an animal is approaching, perhaps priming it to strike immediately when a potential prey item is detected."

Burmese pythons became established in Florida several decades ago as a result of the international pet trade. The largest snakes removed from the Everglades have exceeded 18 feet and 150 pounds. Snakes of this size are capable of ingesting large prey like deer and alligators.

This human risk assessment concluded that although the risk of an unprovoked attack by a Burmese python in Everglades National Park is low, it is not non-existent. Available evidence from captive snakes suggests that even those strikes that result from cases of mistaken identity or defensive behavior may still result in constriction, which can prove fatal to people when a large python or a small human is involved.

The study focused only on the risk associated with Burmese pythons, but did not address other invasive constrictor species, such as the Northern African python, which is also known as the African Rock python, which are also known to be established and breeding in South Florida outside of Everglades National Park. USGS scientists continue to work with partners to better understand the impacts on invasive reptiles in the Everglades, help reduce their spread into new areas and help prevent new species from becoming established.

"Assessing risks to humans from invasive Burmese pythons in Everglades National Park, Florida, USA" by Robert Reed and Skip Snow is published online in the Wildlife Society Bulletin. 

Pollutants Pose Threat to Mekong River Residents

Posted: 27 Feb 2014 07:30 AM PST

Contact Information:

Gabrielle Bodin ( Phone: 337-266-8655 ); Scott  Wilson ( Phone: 337-266-8644 );

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LAFAYETTE, La. – Portions of the Mekong River Basin contain hotspots of persistent organic pollutants that pose a significant threat to the residents and wildlife of the Mekong Basin, according to a new U.S. Geological Survey study.

A research team comprised of members from the University Network for Wetland Research and Training in the Mekong Region, the International Crane Foundation and the USGS found that the total loading of persistent organic pollutants in wetland sediments of the Mekong Basin was generally low, but hotspot sites occurred where concentrations exceeded established ecological risk thresholds. Team members from the University Network are providing the results to officials within their own countries so they can determine how to address the issues.

"The overall results of this study provide crucial baseline data that will guide future development and conservation efforts in the Mekong Basin," said Scott Wilson of the USGS National Wetlands Research Center and co-author of the study. "Future work will focus on the classification and distribution of wetlands in the Mekong River Basin, an investigation into heavy metal contamination, and surface elevation monitoring in the coastal area of Southeast Asia."

Persistent organic pollutants are not readily biodegradable and are known to induce a variety of toxic effects in humans and other organisms. In humans, adverse health effects related to reproductive, developmental, behavioral, neurologic, endocrine, and immunologic processes have been linked to exposure. Since persistent organic pollutants do not degrade easily, they can persist in the environment for long periods of time. The pollutants come from agricultural pesticides, industrial pollutants, and other unintentional by-products. This study focused primarily on persistent organic pollutants used in agricultural practices.

The persistent organic pollutants accumulate in the fatty tissue of fish, amphibians, snakes and water birds that make up a large portion of the local population's diet.  Animals tested in some hotspots, such as the Tonle Sap, are known to have high levels of bioaccumulation.

The international team looked at 531 samples from approximately 450 wetlands across five countries in Southeast Asia and analyzed them for 39 persistent organic pollutants -- in this case organochlorines and PCBs.  

"Conducting quality science at this spatial scale requires intimate knowledge of local areas," said Wilson. "This effort could only be completed with the help of local universities, regional organizations like the International Crane Foundation, and the interdisciplinary science program of agencies like USGS."

Results showed that the use of DDT, a known persistent organic pollutant that has been banned in the study countries, has declined in the region, however, some wetland hotspots were found that contain levels of DDT above established risk thresholds and even suggest continued illegal use. The concentration and distribution of endosulfan, a chemical being phased out in the U.S. and other parts of the world, and its metabolites were also studied and represent a serious problem that requires further study and management action in the Mekong River Basin.

The USGS study, "Persistent Organic Pollutants in Wetlands of the Mekong Basin," was initiated by the U.S. Department of State and was prepared in cooperation with the University Network for Wetland Research and Training in the Mekong Region and the International Crane Foundation.