Long-term changes in the number of diving ducks wintering in Lakes Nakaumi and Shinji, Japan

Q4 Environmental Science

Japanese Journal of Limnology Pub Date : 2020-09-25 DOI:10.3739/rikusui.81.233

Toshiaki Esumi, Toshikuni Kato, Y. Matsuo, H. Kamiya, Yu Ishitobi

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引用次数: 0

Abstract

Many birds migrate during late autumn and stay until early spring at Lakes Nakaumi and Shinji in San-in district, western Honshu, Japan. The numbers of diving duck species Aythya ferina, Aythya fuligula, and Aythya marila, which constitute the majority of wintering bird populations, were determined monthly during the winter season from 1999 to 2015 in the main area of L. Nakaumi, Honjo Area, which is separated from L. Nakaumi by reclamation dikes, and L. Shinji. The mean value in December and January, obtained from changes in the monthly numbers of each diving duck in the three areas, was used as the wintering number. The long-term data showed a declining trend in the numbers of A. ferina and A. fuligula wintering in L. Nakaumi and Honjo Area. In L. Shinji, long-term data for A. fuligula also showed a decline trend, however, the data for A. marila indicated an upward trend. In L. Nakaumi and Honjo Area, the main diet for these diving duck species is the mussel Musclista senhousia, while in L. Shinji they feed on Corbicula japonica. The long-term changes in wintering bird numbers were investigated in relation to changes in food availability and habitat in the two lakes.

查看原文本刊更多论文

日本中海湖和新治湖越冬潜水鸭数量的长期变化

许多鸟类在深秋迁徙，并在日本本州岛西部三林区的中泉湖和新寺湖停留到早春。1999年至2015年冬季，在L.Nakumi的主要地区、与L.Nakumy隔着填海堤的本条地区和L.Shinji，每月都会确定构成大多数越冬鸟类种群的潜水鸭物种Aythya ferina、Aythya fuligula和Aythya marila的数量。根据三个地区每只潜水鸭的月数量变化得出的12月和1月的平均值用作越冬数量。长期数据显示，在L.Nakumi和Honjo地区越冬的a.ferina和a.fuligula数量呈下降趋势。在L.Shinji，A.fuligula的长期数据也显示出下降趋势，然而，A.marila的数据显示出上升趋势。在L.Nakaumi和Honjo地区，这些潜水鸭物种的主要食物是贻贝Musclesta senhousia，而在L.Shinji，它们以日本虫草为食。研究了两个湖泊中越冬鸟类数量的长期变化与食物供应和栖息地的变化之间的关系。

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来源期刊

Japanese Journal of Limnology Environmental Science-Ecology

CiteScore

0.20

自引率

0.00%

发文量

期刊介绍： The Japanese Society of Limnology was founded in 1931 for the purpose of promoting and fostering the study of limnology in the broad meaning of the term. It publishes quarterly "The Japanese Journal of Limnology" and holds an annual meeting consisting of lectures, discussions and symposiums on limnological subjects.