在来種の生態的ニッチ分化が淡水魚侵入への抵抗性を生むことを解明(Native Niche Differentiation Drives Resistance to Freshwater Fish Invasions)

2026-06-09 中国科学院(CAS)

中国科学院(CAS)水生生物研究所を中心とする国際研究チームは、世界2,622の河川流域の淡水魚群集データを解析し、外来魚の侵入を抑制する最も重要な要因が在来魚群集の「ニッチ分化」であることを明らかにした。研究では、在来種間の生態的地位(ニッチ)、機能特性、系統的多様性を定量化し、外来魚の出現頻度や種数との関係を評価した。その結果、在来種のニッチ分化が大きいほど資源利用が効率化され、種間競争が強まることで外来魚の定着や増加が抑制されることが判明した。この傾向は世界の主要な淡水生物地理区すべてで一貫して確認された。一方で、人間活動は外来魚侵入を強く促進し、侵入強度は中緯度地域で最大となった。研究成果は、生物多様性が高いほど侵入を防ぐのか、それとも逆なのかという「侵入パラドックス」に統一的な説明を与え、気候変動や人為的影響が進む中での淡水生態系保全や外来種管理に重要な知見を提供している。

在来種の生態的ニッチ分化が淡水魚侵入への抵抗性を生むことを解明(Native Niche Differentiation Drives Resistance to Freshwater Fish Invasions)

Native niche differentiation promotes biotic resistance to freshwater fish invasions worldwide. (Image by IHB)

<関連情報>

在来種のニッチ分化は、世界中の淡水魚における外来種侵入に対する生物的抵抗力を促進する Niche Differentiation of Native Species Promotes Biotic Resistance to Invasion in Freshwater Fishes Worldwide

Chengzong Tian, Bo Yang, Jorge García-Girón, Zhongyang Li, Zi Xun Kua, Xiaopei Du, Wei Xin, Xiongdong Zhou, Ming Duan, Yushun Chen

Global Change Biology  Published: 14 May 2026

DOI:https://doi.org/10.1111/gcb.70905

ABSTRACT

Understanding the resistance of native fauna to biological invasions is essential for predicting and managing freshwater fish diversity under accelerating global change. Using fish and environmental data from 2622 river basins worldwide, we quantified how niche differentiation, phylogenetic and functional diversity, and richness of native species, as well as environmental factors contribute to non-native fish richness and occurrence. Our results show that niche differentiation of native fishes is the key determinant of biotic resistance: when native species occupy broader and more heterogeneous niche spaces, both the richness and occurrence probability of non-native fishes decline significantly, a pattern that holds consistently across global and biogeographic scales. Functional and phylogenetic diversity exert partially constraining effects, yet their influence varies across invasion metrics and spatial scales, thereby limiting their predictive power. Native richness promotes the naturalization of non-native species but does not significantly influence invasion richness. Notably, non-native fish invasions follow a nonlinear latitudinal gradient, intensify with increasing human pressure, and are positively associated with basin area. These findings demonstrate that freshwater fish invasions are jointly shaped by biotic interactions, environmental filtering, and human activities, with native niche differentiation emerging as the primary driver of biotic resistance. By incorporating niche-based mechanisms, this study provides a unifying perspective for reconciling the invasion paradox and offers a process-based foundation for developing integrated invasion management strategies under global change.

1903自然環境保全
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