USGS brown tree snake research continues at Guam National Wildlife Refuge

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Juvenile Brown Tree snakes (BTS) prefer to eat cold-blooded species like geckos and skinks. This snake was encountered consuming a locally abundant gecko, also thought to be a human introduction to Guam. The abundance of nonnative prey on Guam supports BTS populations and poses challenges to suppression of snakes for native species recovery. (Photo credit: Melia Nefus, USGS.

(USGS) – On May 14, U.S. Geological Survey Director Jim Reilly signed a Memorandum of Agreement with the Department of the Navy and the U.S. Fish and Wildlife Service.

The MOA provides for continuity of operations for the USFWS and the USGS with construction of new office and lab facilities on the Guam National Wildlife Refuge in conjunction with DOD’s construction of a Marine Corps firing range.

“The USGS has a long history of collaborating with the Department of Defense in support of U.S. facilities and force readiness in the INDOPACOM Area of Responsibility. One of our signature efforts ongoing today is a collaboration with DOD, the U.S. Fish and Wildlife Service, and the local government in minimizing the impacts of the invasive Brown Treesnakes (BTS) and improving BTS controls on military lands on Guam,” said Reilly.

USGS scientists and staff associated with the Brown Tree snake Project are co-located at the Guam National Wildlife Refuge at the northern end of Guam in the western Pacific Ocean.

Project staff are developing and testing control tools for invasive Brown Treesnakes, as well as understanding their impacts on Guam’s ecosystems. Project staff also lead the multi-agency Brown Tree snake Rapid Response Team, which responds to invasive snake sightings throughout the Pacific and trains personnel from cooperating agencies to increase the capacity of the team.

Major partners of the USGS Brown Tree snake Project include DOI Office of Insular Affairs, USDA-APHIS Wildlife Services, Department of Defense, the U.S. Fish and Wildlife Service, and State and Island governments.

Accidentally introduced to Guam during or soon after World War II, the Brown Tree snake was a major contributor to the loss of nine of 11 native forest birds and several native lizard and bat species on the island.

Some of these lost species are present in captivity or on other islands in the Marianas, suggesting that recovery of some of Guam’s native biota may be possible. However, prospects for successful recovery are dependent on successfully controlling or eradicating Brown Treesnakes at various spatial scales.

Much of the research conducted by USGS scientists is directed towards improving methods for Control and Landscape-Scale Suppression of the Invasive Brown Tree snake by developing, testing, and validating control tools and by improving understanding of the species’ biology, ecology, and behavior for control purposes.

The USGS Brown Tree snake Project is led by Fort Collins-based principal investigators who oversee research activities conducted by USGS scientists, affiliates from the University of Guam, and cooperators; these projects are aimed at containment, control, management, and detection of the invasive Brown Treesnakes on Guam.

The devastating ecological impacts of Brown Treesnakes on Guam would likely be replicated if the snakes were to become established elsewhere in the Pacific, including Hawai’i or the U.S. Commonwealth of the Northern Mariana Islands. Because Brown Treesnakes are stealthy and often hide in cargo or goods, the risk of accidental transportation of snakes from Guam is high. Partners at USDA-APHIS Wildlife Services conduct highly effective snake trapping and cargo inspections around ports and airports on Guam, and state/territorial partners repeat these actions on recipient islands. However, some Brown Treesnakes have made it through these interdiction nets in the past.

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