There are millions of species of organisms on Earth, living while interacting with one another. This richness is called biodiversity, and it is being lost because of human activities.
Basic Knowledge
Biodiversity: The existence of many kinds of organisms, each having complex relationships with others. There are three levels:
① Species diversity: The existence of many different kinds of organisms.
② Genetic diversity: The fact that genetic information differs among individuals of the same species.
③ Ecosystem diversity: The existence of various ecosystems, such as forests, rivers, oceans, and wetlands.
Endangered species: Species whose numbers have decreased and that face the risk of extinction. In Japan, they are listed on the Red List.
Examples: Japanese rock ptarmigan, Japanese river otter(designated extinct in 2012), crested ibis, Oriental stork, short-tailed albatross, Amami rabbit, Okinawa rail, and others.
Alien species(non-native organisms): Organisms that were not originally present in a region but were brought there by humans. Some are regulated by law as Invasive Alien Species.
Examples include American crayfish・bullfrogs・black bass・bluegill・raccoons・mongooses・common dandelions・Rudbeckia laciniata.
Alien species disrupt the balance of ecosystems by preying on native species, competing with them, and introducing diseases.
Biodiversity（The diversity of species, genes, and ecosystems at three levels）
Endangered species（Species at risk of extinction; listed on the Red List）
Native species（Organisms that have lived in a region since long ago）
Alien species（non-native organisms）（Organisms from another region introduced by humans）
Invasive Alien Species（Alien species that cause serious ecosystem damage and are regulated by law）
Red List（A list of endangered species published by the Ministry of the Environment）
Further Study (Background・Significance)
Specific examples of alien-species damage:
・Mongoose(Okinawa・Amami): Introduced to eliminate habu snakes→preys on native species such as the Amami rabbit. Eradication projects are currently underway.
・Black bass・bluegill(lakes and ponds throughout Japan): Released for sport fishing→devour native fish.
・Raccoon(throughout Japan): Originated as pets→damages crops and enters the attics of temples and shrines.
・Red imported fire ant(ports): Entered from foreign ships→may harm people with its potent venom.
・Giant goldenrod・great leopard plant: Displace native plants.
Significance of biodiversity:
① Ecosystem services: Food supply, purification of air and water, maintenance of soil, raw materials for medicine, tourism resources, and more. Biodiversity is the foundation of human survival.
② Genetic resources: Necessary for breeding and pharmaceutical development. Greater diversity increases the chances of discovering new medicines.
③ Resistance to environmental change: When many kinds of organisms are present, ecosystems are less likely to collapse because of disasters or disease.
International efforts:
・Ramsar Convention(1971): Protection of wetlands and migratory birds.
・Washington Convention(1973): Regulation of international trade in endangered species.
・Convention on Biological Diversity(1992): Adopted at the Rio Earth Summit.
・Aichi Targets(2010, COP10 in Nagoya): Biodiversity targets.
- Biodiversity=three levels: species・genes・ecosystems
- Endangered species=listed on the Red List(published by the Ministry of the Environment)
- Alien species=organisms from another region introduced by humans
- Invasive Alien Species=regulated by law(transport and keeping prohibited)
- Examples: black bass・raccoons・red imported fire ants・mongooses
- Ecosystem services=food・water・air・medicine
- Ramsar Convention・Washington Convention・Convention on Biological Diversity
Points to Note (Easily Confused)
① Distinguish native species(originally present) from alien species(introduced). Even if a species is not from a foreign country, it is an alien species if humans introduce it from another region. ② Not all alien species are bad; those that cause ecosystem damage are regarded as invasive alien species and are of particular concern. ③ Endangered species have levels such as “IA, IB, and II.” ④ Do not confuse the three conventions: Ramsar Convention=wetlands, Washington Convention=international trade, and Convention on Biological Diversity=comprehensive(Rio 1992).
Practice
- Give all three levels of biodiversity.
- What is the list of organisms at risk of extinction called?
- Give one harmful effect of alien species on ecosystems.