Guam is an unincorporated territory of the United States, located in Micronesia. It is the largest and southernmost island in the Mariana Islands archipelago, with volcanic highlands in the south and limestone plateaus in the north. Its ecosystems include tropical forests, wetlands, mangroves, and coral reefs. Guam has faced severe biodiversity loss due to invasive species, most notably the brown treesnake. In recent years, Guam has advanced invasive species management through the work of the Guam Invasive Species Council (GISC), the Department of Agriculture’s Biosecurity Division, and U.S. federal initiatives, aligned with habitat conservation plans under the Endangered Species Act.
Vue d'ensemble
Biodiversity Status
Historically rich bird diversity, now severely reduced due to invasive predators. Coral reefs and mangroves sustain fisheries and coastal protection. Endemic plants and reptiles remain under threat but are protected in reserves. Critical habitat designations (2026) cover ~59,886 acres for endangered species.
Invasive Species Threats
Invasive species include brown tree snake (responsible for near extinction of native birds), feral pigs, cats, vines such as Merremia peltata and Mikania micrantha, coconut rhinoceros beetle, little fire ant that is causing the collapse of native bird populations, crop damage, painful ant stings, and ecosystem imbalance.
National Strategies & Plans
Guam Invasive Species Council coordinates invasive species management. The Biosecurity Division (DOAG) enforces import controls, quarantine, and pest management. The U.S. Fish & Wildlife Service habitat conservation plans integrate invasive species control with endangered species recovery. Focus areas include brown tree snake containment, little fire ant eradication, coconut beetle suppression, and biosecurity enforcement.
