ブラウンペリカン:カリフォルニア州南部沖の繁殖が改善された
Science (New York, N.Y.)
|December 1, 1975
まとめ
カリフォルニアのブラウンペリカンの生産性は,1971年以来,卵の生存率の向上とアンチョウのDDE汚染の減少により改善されています. しかし,繁殖数は人口安定水準を下回っている.
科学分野:
- 環境科学 環境科学
- 野生生物生物学 野生生物生物学
- エコロジー エコロジー エコロジー
背景:
- カリフォルニア・ブラウン・ペリカン (Pelecanus californicus) の個体群は,重大な脅威に直面した.
- DDEの汚染は,卵殻の完全性と生殖成功に影響を与える主要な要因として特定されました.
研究 の 目的:
- カリフォルニアの北部のコロニーのブラウンペリカンの生産性の変化を 1971 年以降に評価する.
- 新生児の発生率と卵の生存率の改善に寄与する要因を調査する.
主な方法:
- 繁殖コロニーの長期監視.
- 新生児の発生率と卵の生存データに関する分析.
- 主要な食物源であるアンチョビのDDE汚染レベルの評価.
主要な成果:
- カリフォルニアのブラウンペリカンの生産性は,1971年以来大幅に改善されました.
- 新生児の発生率は上昇し,1974年には巣あたり0.9匹の幼生に達した.
- 卵の生存率と卵殻の状態の改善は,アンチョウのDDEレベルの低下と相関しています.
結論:
- アンチョウのDDE汚染の減少は,カリフォルニアのブラウンペリカンの繁殖成功に好影響を与えている.
- 生産性が向上したものの,繁殖数は依然として人口安定のために不十分である.
- 人口の長期的な回復を確実にするためには,さらなる監視が必要である.
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