Tetsuo SHIMADA is a research section head in the Miyagi Prefectural Izunuma-Uchinuma Environmental Foundation, northern Japan. He is vice president of The Ornithological Society of Japan. Lake Izunuma-Uchinuma is Ramsar site and EAAFP site. He and his team of researchers have been undertaking a tracking survey and elucidation of wintering ecology of waterfowl wintering in Japan including mainly the lake.
Japan has the largest population of waterfowl wintering in eastern Asia as exemplified by Greater White-fronted Geese, Whooper, and Bewick’s Swans, and several ducks. Lake Izunuma-Uchinuma, located in northern Japan, is one of the largest wintering sites for waterfowl in Japan. Especially, the population of Greater White-fronted Geese around the lake is 280,000 and occupies more than 90% of the whole population in Japan. Lake Izunuma-Uchinuma is a very shallow lake surrounded by rice fields. Its maximum depth is 1.6m, and the size, is 491ha. Geese, Swans, and ducks widely demand a variety of foods like plants, fishes, and crustaceans in/around the lake that constitute an essential basement of the regional ecosystem. My team and I have been studying the migration and wintering ecology of waterfowl in Lake Izunuma-Uchinuma for 30 years. First, the migration of geese, swans, and ducks that have been identified so far will be described. Greater White-fronted Geese departed from Lake Izunuma-Uchinuma and reached the Bering Sea coast via Hokkaido and the Kamchatka Peninsula. Whooper swans departing from Lake Izunuma-Uchinuma traversed Hokkaido and the Sea of Okhotsk before reaching the Russian interior. This is followed by an explanation of the wintering ecology of Greater White-fronted Geese, Black Brant, Whooper Swans, Mallards, and Northern Pintails. The geese foraged in farmland during the day, and the swans in the lake foraging for rhizome of lotus. Ducks foraged in farmland at night. Lake Izunuma-Uchinuma has high biodiversity: mammals, birds, insects, plants, and so on. The total number of species inhabiting in and around the lake is about 1,500 species. Finally, I introduce conservation activities such as the eradication of invasive fish, largemouth bass to conserve biodiversity.
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