Invasive Brown Tree Snake Threatening Hawaii

Activists are advocating for increased funding and broader authority for the Hawaiian Department of Agriculture to act swiftly and decisively to address the invasion of Hawaii’s island habitats by the brown tree snake. 

The non-native species is considered a threat to the state’s fragile ecosystems and to human health, as its venom is poisonous and it has previously decimated populations of native birds and lizards in neighboring Guam. 

The Department of the Interior recently allocated more than $1.2 million to the U.S. Geological Survey to “continue developing and testing tools aimed at further increasing efforts to capture and control the invasive brown tree snake in Guam.”

Conservationists are hoping the developments will be useful in launching an early strike on the snake in Hawaii.  Because the snake reproduces often and has no natural predators, its population is expected to proliferate if swift action is not taken. 

The snake’s populations are naturally limited in their native habitats by the scarcity of their food source: lizards and birds.  On islands like Guam and Hawaii, the food is plentiful.  The snake colonized the entire island of Guam in 18 years, and “is directly responsible for the extinction or local extirpation of nine of 13 native forest birds and three of 12 native lizards.” 

Firsthand accounts of walks through Guam’s forests often mention the absence of bird song and the nuisance of insects, whose populations are uncontrolled without their natural predators. 

“At present, even small mammals are extremely rare in most forested habitats of Guam,” reported the USGS, and the snake “remains the leading cause of endangerment for the few remaining native vertebrates,” according to the state of Hawaii

Christy Martin of the Coordinating Group on Alien Pest Species characterized the 1950s brown tree snake invasion of Guam an “environmental catastrophe,” particularly with regards to its detrimental effects on agriculture. 

The proliferation of insect pest populations from the loss of most insectivorous birds and many lizards threatens agricultural crops, public health, and the island’s ecology. 

“Examples of such problems caused by insect pests include potential outbreaks of dengue fever carried by mosquitoes, defoliation of extensive stands of the tangan tangan tree by an insect arriving from Hawaii, and a host of insects that reduce yields of fruits and vegetables grown by Guam’s farmers and rural residents.”

While nearly 200 humans have suffered from brown tree snake bites, the arboreal snake has proven to be a further nuisance by climbing power lines and shorting circuits in the process.  The snakes have caused an average of one power outage every three days in Guam since 1980. 

Because many Pacific Island ecosystems are similar to Guam’s and they are directly linked  through commerce, the introduction and establishment of brown tree snake populations on other oceanic islands is likely to have repercussions as those in Guam, according to the USGS. 

“This is particularly relevant to islands that support unique species, have less complex power supply systems, and whose economies are largely based on tourism.”

The devastation this invasive species has caused is clear, and for that reason, a dire issue facing Hawaii and other Pacific islands.  While self-sustaining populations of the snake are not thought to have been established in Hawaii yet, “constant vigilance is required to avert this disaster,” said state officials.   

To support the federal and state initiatives to control invasive species introduction, you can sign ForceChange’s petition to stop the brown tree snake’s invasion of Hawaii

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