Invasive species can "invade" any area and immediately threaten the balance of the ecosystem. Below is the brown tree snake, an invasive species to the pacific island of Guam.
The brown tree snake began to show up in Guam sometime between the 40s and 50s. No one knows exactly how the snake invaded Guam, although speculation is that it traveled here accidentally on imported human cargo.
The snake is native to Indonesia, Australia, and Papua New Guinea. It has become highly invasive since arriving to the island.
It has completely wiped out species of birds in Guam. One of its most famous victims is the Guam Rail pictured below.
The Guam rail is important because it is only found in Guam. The brown tree snake has effectively wiped out any trace of the Guam Rail in the wild. Any trace of the Guam Rail now lies in specially managed habitats by Guam's government.
The brown tree snake multiplies fast. According to National Geographic's Dan Stone, who wrote an article on the invasive species, the brown tree snake population in Guam is estimated to be around one million.
The threat of the snake to Guam is real and nationally recognized. In 2013, The U.S. government dropped 2,000 dead mice on the island. The mice were filled with acetaminophen, commonly found in Tylenol, and is poison to the snake. Many native Guamanian are skeptical that the project will truly rid the island of the snake.
The problem which most concerns the U.S. government is the eventual spread of the snake to Hawaii, which rely on its natural plants and species as a tourist attraction. So far there is no trace of the snake in other islands, but it is only a matter of time until the snake accidentally makes it on a piece of cargo or a humans suitcase.
Even if the snake is eradicated, there are still many other invasive species of plants and animals that threaten the ecosystem of Guam. According to the Global Invasive Species Database, there are currently 129 invasive species in Guam.