Why are invasive species a problem?
The introduction of invasive species can have a dramatic effect on our natural resources, human health, and economy. When non-native species are introduced into an ecosystem in which they did not evolve their populations sometimes explode in numbers. The reason for this is that in a natural or native community, species evolve together into an ecosystem with many checks and balances that limit the population growth of any one species. These checks and balances include such things as: predators, herbivores, diseases, parasites, other organisms competing for the same resources and limiting environmental factors. These checks and balances form the complex web of life that makes up an ecosystem and in which a native species competes for survival. However, when an organism is introduced into an ecosystem in which it did not evolve naturally, it no longer has those limits and its numbers can sometimes dramatically increase. The unnaturally large population numbers can then have severe impacts
