id	author	title	date	pages	extension	mime	words	sentences	flesch	summary	cache	txt
cord-016379-lcog1654	Pimentel, David	Plant,Animal, and Microbe Invasive Species in the United States and World	2007		.txt	text/plain	5743	313	57	Calculating the negative economic impacts associated with the invasion of exotic species is difficult.For a few species, there are sufficient data to estimate some impacts on agriculture, forestry, fisheries, public health, and the natural ecosystem in the US and worldwide. Worldwide, an estimated 30,000 species of exotic plants have been intentionally introduced as crops, and have escaped to become established in various natural ecosystems. In the United States, introduced plant species are spreading and invading approximately 700,000 ha of US natural ecosystems per year (Babbitt 1998) . In the Great Lakes, for instance, nearly 50 invasive species are found, and these invaders are causing an estimated $ 5 billion in damages to the fisheries per year (Pimentel 2005) . This investigation reports on various economic damages associated with invasive species in various nations of the world that total more than $ 1.4 trillion per year (Pimentel 2002) .	./cache/cord-016379-lcog1654.txt	./txt/cord-016379-lcog1654.txt