Plants, birds, feral pigs: the invasive species that cost the US millions

Invasive species are estimated to cost the US $120bn in damages annually - here are five that concern experts

Globally, invasive species account for $423bn in losses each year, with a significant portion concentrated in the United States. They are estimated to cost US $120bn in damages annually, though the number has probably changed as the latest assessment dates back to 2005.

Whether its travel or the transportation of goods, human activity has contributed to the introduction of over 37,000 species into new habitats. Animals, plants, algae and disease-causing insects are introduced to new places by land or by water, either intentionally or by accident. Once established, they can out-compete native species, damage existing ecosystems and transmit diseases.