Economic and environmental threats of alien plant, animal, and microbe invasions

Quantifying the environmental damage and loss of biodiversity due to alien species invasions worldwide is complicated by the fact that only some 1.5 million of the estimated 10 million species on earth have been identified and described. The total numbers of introduced species in the United States, the United Kingdom, Australia, South Africa, India, and Brazil range about 2000 to 50,000 species