• Kyodo


Japan’s wetlands and mudlands produce an economic value of ¥1.4 trillion to ¥1.6 trillion a year in terms of water purification and food supply, the Environment Ministry estimated in a report urging ecosystem preservation Friday.

These natural assets are valuable and preserving them is important, the report said.

Wetlands and mud flats clean up water and offer food, materials and recreation sites, ministry officials said in calculating the values of the natural assets. In terms of water-cleaning capacity, the ministry set out the costs for building and running water purification plants.

The study covered some 850 swamp sites of about 110,000 hectares, including the Kushiro wetlands on Hokkaido and the Oze marshland, which stretches over Fukushima, Gunma and Niigata prefectures on Honshu.

It also covered around 1,300 sites classified as mud flats, totaling 50,000 hectares and including the Fujimae tidal flat in Aichi Prefecture on Honshu and the Ariake Sea, bordered by Fukuoka, Saga, Nagasaki and Kumamoto prefectures on Kyushu.

Wetlands and related mud environments can be used to provide food, construction materials and recreation possibilities, and also pose possibilities as water filters, ministry officials said. In calculating their value, the ministry put a figure on the likely cost of building and maintaining water purification plants.

The report said swamps produced an estimated annual economic value of ¥840 billion to ¥970 billion a year and mud flats ¥610 billion.

Government data show that the ecosystems are shrinking. Over the past century, about 60 percent of the wetlands and 40 percent of the mud flats have disappeared because of human activity such as development.

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