Artificial Nature Biotope-Study-Invasion of ecosystem and the naturalized species

Study

Invasion of ecosystem and the naturalized species

　With the ecosystem, we gathered up the environment that surrounded creatures which were in the constant area and with a closed system.
　　Though originally they were not in the area, naturalized species are brought by human activity from other areas.
　　The local ecosystem collapses by the naturalized species now that become the problem all over the world.　

Imminent naturalized species

・　Large-mouth bass: An enterpriser takes largemouth bass home from the United States, and what they discharged into Lake Ashi of Hakone.　　It became the boom among anglers and it was released to each place and spread afterwards.
　　Now we try to get rid of them not to have an influence on the ecosystem.

・　 American crawfish: What was brought into Japan for bait use of the bullfrog.　 They ran away from rearing pond and spread out in the whole country because a few strength and natural enemies such as the propagative power afterwards.　Because this crawfish is omnivorous, aquatic food and small animal are eaten, and roots of the rice are eaten away. 　They spread too much and cannot get rid.

・ Mississippi red-ear turtle: What was imported by the United States.　 They were sold by the name of "green turtle" and were kept as pets and spread out in the whole country. 　But this tortoise grew too much big, and breeders threw them away and they spread in the whole country. 　The aquatic plants such as lotuses are preyed on by this tortoise, and the harvests of the lotus root decrease. 　You mustn't throw away the creatures keeping as a pet easily.

Measures to a naturalized species

　　Such measures are performed.
・ Japan: We regulate it for transportation, import to prevent the damage with the foreign naturalized species, and the naturalized species method which established what a country and the local government prevent as needed in the outdoors.
　　　In the science of the junior high school, the issue of naturalized species are taken up.

・The United States of America: The Lacey method which is the federal law regulates the circulation of the naturalized species. 　In addition, even the wild animal method of each state regulates the naturalized species.

・ Europe: Naturalized species measures are obliged by the civil law of each country.
　　