ABSTRACT
Invasive plants and animals are a major threat to natural ecosystems and their species, second only to direct destruction of habitats by humans. The impacts of alien invasive species are immense, insidious, and usually irreversible. Alien invasive species are found in all taxonomic groups, including viruses, fungi, algae, mosses, ferns, higher plants, invertebrates, fishes, amphibians, reptiles, birds, and mammals. Extinctions of native species by aliens are enormous, and the ecological cost is the irretrievable loss of native species and ecosystems. The direct economic costs of alien invasive species are also remarkable. This problem is growing in severity and geographic extent as the volumes of international trade and travel increase. Communities all over the world are taking appropriate initiatives that contribute to better management practices and a reduced incidence of biological invasion.
