熱帯の窒素固定樹種における広範囲にわたる草食性コスト

Will Barker¹, Liza S Comita^2,3, S Joseph Wright³

¹Ecology and Global Change, School of Geography, University of Leeds, Leeds, UK.

Nature

|December 8, 2022

まとめ

植生食は熱帯雨林に重大な影響を及ぼし,窒素を固定する木は固定しない木よりも26%の被害を受けています. この動物の草食は重要な共生的な窒素固定を制限し森林の炭素吸収に影響を及ぼします

科学分野:

熱帯生態系
森林の炭素循環
植物と動物の相互作用

背景:

成熟した森林と回復している森林は重要な炭素吸収源として機能するが,その容量は窒素の可用性によって制限される.
窒素を固定する木は細菌との共生で熱帯雨林における新しい窒素の主要な天然源です
窒素を固定する木は限られているので熱帯の生態系への窒素の供給を制限するのは何なのか疑問が湧いてきます

研究の目的:

熱帯雨林における共生的な窒素固定を制限するかどうかを調査する.
窒素を固定する木は他の木類と比較して草食性の高い割合を経験しているかどうかを判断する.
窒素を固定する木の草食性の炭素のコストを評価し窒素に富んだ葉と関連しているかどうかを調べました

主な方法:

パナマの43の熱帯樹種から350の苗から1626の葉を分析した.
窒素を固定する木と固定しない木の草食レベルを比較する.
両樹種における草食と関連した炭素の機会コストの評価

主要な成果:

窒素を固定する木は固定しない木よりも26%多く草食をしており,苗木の成長と生存に影響を及ぼした.
草食による炭素機会コストは,窒素固定樹では34%高く,窒素固定のコストを上回りました.
窒素を固定する木の草食性の高い割合は,葉の窒素含有量の高さによるものではなかった.

結論:

動物による草食は,熱帯の生態系における共生的な窒素固定を制限する重要な要因である.
この草食による制限は,熱帯の炭素吸収場内の窒素の制限を緩和する窒素固定の役割を制限する可能性があります.
熱帯雨林の炭素貯蔵の将来を予測するには植物と草食動物のダイナミクスを理解することが重要です

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