Environment Signs of extinction lurking in tidal flats - Loss of Ipominae (around 2007)

Environment Signs of extinction lurking in tidal flats - Loss of Ipominae (around 2007)

Around 2007, Japan's coastal environment was undergoing rapid ecological change. A survey conducted by the Ministry of the Environment at 157 tidal flats across Japan provided a symbolic example. It became clear that the Ibuminina, a type of mollusk that had been distributed from Tohoku to Kyushu, had disappeared from its traditional distribution area, not being found in the Kanto region.

Tidal flats are not only habitats for a variety of organisms such as crabs, shellfish, and mussels, but also serve as an important environmental infrastructure that provides ecosystem services to human society by purifying water quality through the intersection of seawater and river water. However, with urbanization and industrial development since the period of high economic growth, tidal flats have been rapidly lost in various areas such as Tokyo Bay, Ise Bay, and the Ariake Sea. Direct destruction by land reclamation and port development, and compound factors such as dredging, water pollution, and invasion of alien species have accelerated the loss of biodiversity.

In the early 2000s, the "National Biodiversity Strategy" was formulated, and internationally, the strengthening of conservation was called for at the COP (Conference of the Parties to the Convention on Biological Diversity), and the importance of tidal flats was beginning to be recognized anew in Japan as well. The disappearance of Ibuminina was a specific case that sounded a warning bell against this trend. The Ministry of the Environment has stated that it will continue to conduct surveys of tidal flats and seek conservation measures, but many tidal flats have already been irreversibly lost, highlighting the difficulty of recovery.

This case shows that the loss of organisms that occurred on a small local tidal flat was closely linked to Japan's overall environmental policy and the international biodiversity conservation debate. In other words, the destruction of the tidal flat and the signs of the extinction of the Ibo minina were a microcosm of the "sustainability crisis" that Japan faced at the time.