Invasive species are a significant threat to many native habitats and species of the United States and a significant cost to agriculture, forestry, and recreation. The term "invasive species" can refer to introduced or naturalized species, feral species, or introduced diseases. Some species, such as the dandelion, while non-native, do not cause significant economic or ecologic damage and are not widely considered as invasive. Overall, it is estimated that 50,000 non-native species have been introduced to the United States, including livestock, crops, pets, and other non-invasive species. Economic damages associated with invasive species' effects and control costs are estimated at $120 billion per year.