Physical features of Otomonuma

A reservoir constructed in 1675 to irrigate rice fields. Water was supplied from surrounding hills and a river Yoneshiro-gawa originating in the Shirakami Mountains, a World Heritage site.

Location: 40°10'N, 140°04'E

Area: 55 ha

Protection status: Prefectural Wildlife Protection Area, November 1998 - October 2008

Noteworthy flora:

• Emerged vegetation: Phragmites, Zizania, Acorus, Scirpus

• Lowland vegetation: Lythrum, Lysimachia, Polygonum

• Floating-leaved vegetation: Trapa, Nelumbo, Nuphar, Potamogeton

Waterbirds in Otomo-numa

• Main flocks (>1% of populations): White-fronted Goose (Anser albifrons), Middendorf's Bean Goose (A. fabalis middendorfi), Whooper Swan (Cygnus cygnus), Bewick's Swan (C. bewickii)

• Rare species: Ciconia boyciana, Platalea minor, Anser cygnoides, A. caerulescens, Branta canadensis leucopareia, B. bernicla, Tadorna tadorna, Philomachus pugnax, Tringa erythropus

Habitat use by Anatidae populations

• Otomo-numa supports large numbers of Anatidae populations in autumn and in spring.

• Goose flocks roost in the night and forage in the morning and evening within the reservoir, while during the daytime they visit rice fields nearby for foods.

• The number of goose flocks in spring is more than twice as large as that in autumn.

  Peak numbers of goose populations in autumn and spring in the Otomo-numa

  Species	1998 autumn	1999 spring	2001 spring
  Middendorf's Bean Goose	4,000	8,500	58,550
  Thick-billed Bean Goose
  White-fronted Goose	10,000	30,000
  Swan species			7,500
  Duck species			20,000

The management authority of the Site is:

Noshiro City Government, Division of Environment
Kamimachi 1-3, Noshiro, 016-8501 Japan
TEL +81-185-89-2172 / FAX +81-185-89-1769
E-mail: kankyoⓐcity.noshiro.akita.jp
URL <English>: http://www.city.noshiro.akita.jp/eng/index-e.html
URL <Japanese>: http://www.city.noshiro.akita.jp/

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