捕食者の多様性は,トロフィックカスケードを抑制する.
Deborah L Finke1, Robert F Denno
1Department of Entomology, University of Maryland, College Park, Maryland 20742, USA. dfinke@umd.edu
Nature
|May 28, 2004
まとめ
食物網における捕食者の多様性の増加は,トロフィックカスケードを弱め,自然敵が草食動物に与える影響を弱め,最終的には植物生産性に影響を及ぼします. これは,より高いトロフィックレベルの多様性が生態系の機能をどのように変化させるかを強調しています.
科学分野:
- エコロジー エコロジー エコロジー
- エコシステムのダイナミクス
- フードウェブの相互作用
背景:
- 食物網の複雑さは,陸上のトロフィックカスケードを弱体化させるという仮説がある.
- 捕食者の多様性は,ギルド内捕食と共有の獲物のダイナミクスを導入することによって,食物網の複雑さを増加させることができます.
- 理論によると,捕食者の多様性の増加は,草食動物に対する捕食を緩和し,一次生産に対するカスケード効果を抑える可能性がある.
研究 の 目的:
- 肉食動物の多様性が,自然に生息する地上のシステムにおける一次生産性を媒介する役割を,実証的に調査する.
- 草食動物と植物生産性に対する単純な vs 多様な捕食者集団の影響を比較する.
- 捕食者の多様性が増加すると,トロフィカルカスケードが弱まるという仮説を検証するために.
主な方法:
- 沿海沼地の草食動物と植物の生産性に対する節足類の捕食者の影響の比較.
- 捕食者の多様性を実験的に操作し,単純な食物網 (単一の捕食者の種) と複雑な食物網 (多様な捕食者の集合体) を対比する.
主要な成果:
- 強化された捕食者の多様性は,草食動物に対する自然の敵の影響を抑制することが示されました.
- 捕食者の多様性の増加は,トロフィカルカスケードの弱まりにつながった.
- 高いトロフィックレベルの多様性における変化は,生態系の機能を大幅に変化させた.
結論:
- 捕食者の多様性は,陸上の生態系におけるトロフィックカスケードの強さを媒介する上で重要な役割を果たしています.
- 多様な捕食者集団によってもたらされる複雑さは,主生産性などの生態系機能を大幅に変化させることができます.
- 研究結果は,生態系の安定と機能にとって,より高いトロフィックレベルでの生物多様性の重要性を強調しています.
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