塩分が高山湖の大型底生無脊椎動物群集を形成することを解明(Salinity Shapes Macroinvertebrate Communities in Alpine Lakes)

2026-07-21 中国科学院(CAS)

中国科学院(CAS)水生生物研究所(IHB)の研究チームは、青海・チベット高原の40湖・77地点を調査し、高山湖における底生大型無脊椎動物群集は塩分濃度(塩分)が生物多様性や生態機能を左右する最も強い関連要因であることを明らかにした。38,295個体を解析した結果、塩分濃度の上昇に伴い分類学的・機能的多様性は一貫して低下し、低塩分湖では指標種や多様な機能形質が維持される一方、高塩分湖では耐塩性昆虫が優占した。また、中程度の塩分域は群集形成メカニズムが確率的過程から環境選択(決定論的過程)へ移行する重要な境界であり、生物多様性の減少が加速することが示された。さらに、塩分上昇は淡水由来種の消失を招き、淡水化よりも地域全体の多様性や機能的独自性への影響が大きいことがシミュレーションで示された。研究チームは、低・中塩分湖を生物多様性保全の優先対象とするとともに、栄養塩や生産性、生息環境、生物間相互作用なども含めた長期モニタリングの必要性を提言している。

塩分が高山湖の大型底生無脊椎動物群集を形成することを解明(Salinity Shapes Macroinvertebrate Communities in Alpine Lakes)
Salinity-driven biodiversity erosion and community assembly shifts in the global alpine lake hotspot. (Image by IHB)

<関連情報>

塩分濃度の変化が高山湖の大型無脊椎動物群集を再編成する Salinity Variation Reshapes Macroinvertebrate Communities in Alpine Lakes

Baoqiang Wang;Xiong Xiong;Jiahao Zhang;Yongjing Zhao;Xiongdong Zhou ;Yongde Cui
Environmental Science & Technology  Published:July 10, 2026
DOI:https://doi.org/10.1021/acs.est.6c03770

Abstract

Global lakes have experienced unprecedented salinity variation in recent decades, yet its ecological consequences in high-altitude ecosystems remain poorly resolved. Here, we quantified global patterns of salinity variation in alpine lakes and conducted extensive field surveys at 77 littoral sites across 40 lakes on the Qinghai–Tibet Plateau, which hosts nearly 40% of the world’s alpine lakes and spans a broad salinity gradient (0.05–45‰). We integrated multidimensional diversity and assembly mechanism analyses to assess macroinvertebrate responses to salinity variation. Salinity emerged as the dominant measured correlate of macroinvertebrate communities across alpine lakes. Across taxonomic and functional dimensions, local diversity decreased monotonically with rising salinity. Community assembly shifted sharply along the gradient: deterministic filtering dominated high-salinity lakes (>7‰), mixed processes characterized moderate salinity (0.5–7‰), and low salinity (<0.5‰) exhibited a higher apparent stochastic component that may partly reflect unmeasured deterministic factors. At the taxon level, three contrasting adaptive strategies─strict halophiles, broadly euryhaline taxa, and low-optimum but wide-tolerance groups─revealed pronounced ecological divergence under saline stress. Simulated salinity variation further indicated asymmetric responses of regional biodiversity and functional distinctiveness, with salinization causing greater losses than freshening. Moderate-salinity lakes represented a critical mechanistic threshold, where the balance between deterministic and stochastic processes shifted and where regional diversity erosion accelerated. These findings suggest that salinity variation structures alpine lake macroinvertebrate communities across multiple biodiversity dimensions and assembly pathways, with important implications for conserving high-altitude ecosystems under ongoing global environmental change.

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