Battles among Species-The Encroachment of Alien Species

Alien species refer to those not native to a given area. To be exact, its meaning is opposite to that of native species.

An alien species is often taken away from its natural habitat by humans, whether intentionally or unintentionally, and becomes alien to another habitat. An alien species can damage the ecosystem of the habitat it is introduced to if the habitat is environmentally similar to its original home but without its natural enemies, as well as when this species has strong breeding abilities. Basic characteristics of alien species include strong reproductive and dispersal abilities, as well as strong adaptive abilities and vitality. Usually they can outnumber or even replace the native species of their new habitat.
Strictly speaking, all species on earth were once alien species since almost all of them invaded new areas and whose distribution ranges changed due to climate shifts. Nevertheless, alien species here refers to those introduced from other areas within a short period of time. There are many ways of introduction, including smuggling, which is the illegal introduction of species via various modes of transport, or through imported goods. Some species are introduced legally for people’s preferences or daily needs, such as medicines, pets, flowers and plants, green manure, etc. Not all alien species incur negative impacts -- plums from California and cherries from the United States are positive examples. However, the results of introducing alien species can be disastrous if it is not under human control. The so-called beneficial or verminous species are in fact determined by human standards. People often import species for selfish intentions, or even out of ignorance, thus harming the natural ecosystem. When the consequences start to affect humans, it is usually too late to restore the now-disrupted ecological balance. Since prevention is far more effective than restoration, we should be more aware of related preventative measures and solutions by acquiring an insight on alien species.