森林における「反独占」メカニズムの解明(SYSU team uncovers a forest “anti-monopoly” mechanism)

2026-04-30 中山大学(SYSU)

中山大学生態学院の研究チームは、森林の生物多様性を維持する「反独占」メカニズムを解明した。約200年来の謎である緯度多様性勾配に対し、個体間の単純な競争ではなく、周囲全体との「高次相互作用(HOIs)」が鍵であると提唱し、6大陸32観測区・300万本以上の樹木データを用いて初めて全球規模で実証した。これらの相互作用は優占種の独占を抑え希少種の生存を助け、特に熱帯で強く働くことで高い種多様性を生み出す。約40%の種に影響する基本原理であり、森林再生には個体植栽ではなく相互作用ネットワークの再構築が重要と示された。

森林における「反独占」メカニズムの解明(SYSU team uncovers a forest “anti-monopoly” mechanism)
Latitudinal changes in pairwise and HOIs for growth models.

<関連情報>

高次相互作用は緯度方向の樹木多様性勾配を増強する Higher-order interactions enhance the latitudinal tree diversity gradient

Yuanzhi Li  (李远智),Junli Xiao  (肖俊丽),Yuan Jiang  (江园),Stuart Joseph Wright,Margaret M. Mayfield,Oscar Godoy,Alfonso Alonso,Kristina J. Anderson-Teixeira,Jennifer Baltzer,Joseph D. Birch,Pulchérie Bissiengou,Norman A. Bourg,Warren Brockelman,David F. R. P. Burslem,Min Cao  (曹敏),Keith Clay,Stuart J. Davies,Qingqing Du  (杜晴晴),Sisira Ediriweera,Anna Feistner,Edwino S. Fernando,Gregory S. Gilbert,Zhanqing Hao  (郝占庆),Jan Holík,… Chengjin Chu  (储诚进)
Nature  Published:29 April 2026
DOI:https://doi.org/10.1038/s41586-026-10434-6

Abstract

The global decrease in species diversity from low to high latitudes is among the most robust biogeographic patterns1,2. There is continuing debate on the contribution of conspecific negative density dependence (CNDD) to the latitudinal diversity gradient evident for trees3,4. Theory suggests that CNDD based on pairwise interactions alone is not sufficient to explain the intricacies of diverse communities, because higher-order interactions (HOIs) may greatly modify these interactions5,6. However, there has been a lack of empirical studies investigating how HOIs intertwine with pairwise interactions and how they may contribute to the latitudinal tree diversity gradient. Here we examined both pairwise interactions and HOIs across 32 large permanent forest plots, most in the northern hemisphere. We detected evidence of HOIs in 40% of the 1,543 species–plot combinations for tree growth, and 23% of the 1,340 such combinations for tree survival, with the strength of these interactions declining with latitude. HOIs were found to benefit rare species but disadvantage common species, suggesting a potential mechanism promoting species diversity. This stabilizing effect weakened towards higher latitudes, consistent with the latitudinal tree diversity gradient. Our findings reveal an important interplay between pairwise interactions and HOIs in promoting the latitudinal tree diversity gradient and help to clarify the contribution of CNDD to this biogeographic pattern.

1304森林環境
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