Biodiversity is the variation and variety of genes, organisms and species found in an ecosystem. As biodiversity decreases, the vulnerability of an ecosystem to pests and diseases increases. Because the makeup of communities is not always studied, when biodiversity decreases, it is not noticed. It is important to have naturalist biologists who can identify which species are indigenous and which are not, as well as which have disappeared. Introductions do not always have a negative impact.
Exotic species can help an ecosystem by providing a missing link in a failing food chain.
Some scientists believe that introductions can also be beneficial by preserving species in cases where they are endangered or threatened in their natural habitats. Sometimes introducing them into a different habitat enables them to survive, and thus preserve biodiversity. Economic Impacts Introduced non-native species may cause widespread destruction by rapidly taking over an area and eliminating economically profitable native species. This can result in enormous spending by state and federal agencies as they attempt to eradicate pests and restore natural species. A study published by the US Congress, Office of Technology Assessment, Harmful Non-Indigenous Species in the United States , finds that the US alone spends hundreds of millions to perhaps billions of dollars trying to repair the damage of harmful exotic species.