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Kushiro, Hokkaido
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Kushiro Shitsugen is Japan's largest wetland, spreading across roughly 20,000 hectares of eastern Hokkaido.
About 6,000 years ago, the present wetland was covered by the sea. Peat and marsh vegetation gradually replaced the retreating water.
Kushiro became Japan's first Ramsar Convention wetland on June 17, 1980.
Ainu communities around Lake Tōro gathered pekanpe, water-caltrop fruits that could be dried and stored as winter food.
Lake Tōro also supports wakasagi, and winter ice fishing remains one of the area's characteristic seasonal experiences.
Kushiro Shitsugen was designated a National Park in 1987, seven years after receiving Ramsar recognition.
The park protects 28,788 hectares, including wetland, lakes, rivers and surrounding hills.
Roughly 80% of the wetland is low moor, dominated by reeds, sedges and alder communities rather than sphagnum bog.
More than 700 plant species have been recorded in the wetland and surrounding areas.
Around 200 bird species have been recorded here, along with 39 mammals, 38 fish species and roughly 1,100 insects.
The red-crowned crane, known in Japanese as tanchō, survived around Kushiro after it was once feared lost from Japan.
In Ainu tradition, the red-crowned crane is known as sarurun kamuy, a spiritual being associated with the wetland.
Red-crowned cranes live around Kushiro throughout the year rather than appearing only during migration.
Winter is courtship season, when pairs perform their famous calling and dancing displays.
Conservation efforts including winter feeding helped Japan's red-crowned crane population recover dramatically from near disappearance.
The Siberian salamander found here is considered an Ice Age survivor with an exceptionally restricted Japanese distribution.
Kushiro hanashinobu is another Ice Age relic, producing violet flowers in June and July.
Kushiro Shitsugen supports itō, a rare giant freshwater fish and one of Japan's most remarkable river species.
Lake Tōro, Lake Shirarutoro and Lake Takkobu are marine-relict lakes, remnants of the time when the wetland basin was connected with the sea.
A marine crustacean survives in Lake Tōro, another biological reminder that today's inland wetland was once seawater.
The eastern side of the wetland is slowly subsiding while the western side tends to rise, helping explain why lakes cluster in the east.
That same eastward tilt helps explain why the Kushiro River runs along the eastern side of the wetland.
Yachibōzu, sometimes called marsh monks, are strange sedge hummocks formed as new roots grow above older root masses.
Roughly 400 archaeological sites from the Paleolithic through Ainu cultural periods surround the wetland.
Many archaeological sites cluster beside lakes and the Kushiro River, where water provided food and transportation.
Tōro comes from the Ainu to-oro, a place associated with a lake or marsh, preserving the landscape in its name.
Kushiro's older Ainu name was Kusuri, although its exact original meaning remains uncertain.
The wetland lost more than 20% of its area during roughly the latter half of the 20th century through agriculture and urban development.
River straightening and forest clearing increased sediment and nutrients entering the wetland, contributing to drying and ecological change.
Today's restoration program aims toward the ecological conditions that existed around 1980, when Kushiro entered the Ramsar Convention.
When Lake Tōro freezes, moving ice may form ridges called omiwatari, a Japanese name evoking the crossing of the gods.
Steller's sea eagles and white-tailed eagles join the wetland's winter birdlife, making the cold season one of Kushiro's richest wildlife periods.
