How did alien species reach the South and Southwest?
For more than 2,000 years, Native Americans moved plants and animals all over the South and Southwest. Starting in the 1500s, the number of new exotic species as well as the speed at which they moved increased. The Spanish brought exotic agricultural crops and domestic animals from other parts of the world to the Southwest during the Spanish conquest. The new species introduced to the Southwest between 1500 and 1900 were accompanied by changes in physical conditions in the landscape that accelerated the naturalization of these exotics. Many vegetative species were planted for soil stabilization or to stop erosion and for forage for grazing cattle. At the same time, native species were declining. The arrival of the railroad resulted in another increase in invasive species. With the development of roads, airlines, and global commerce, species can now travel from one corner of the world to the South and Southwest in a matter of hours.
