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鉄道建設が外来植物の定着に有利な条件を生み出す可能性(Railway Construction May Create Favorable Conditions for Invasive Plants)

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2026-07-13 中国科学院(CAS)

中国科学院(CAS)西双版納熱帯植物園(XTBG)の研究チームは、大規模な鉄道建設が土壌環境や地下の菌類群集を変化させ、外来植物の侵入を促進することを明らかにした。中国・ラオス鉄道沿線の14駅と周辺自然地を含む84調査区を解析した結果、駅周辺では土壌有機炭素、全窒素、水分が減少し、pHや養分バランスが変化していた。また、土壌菌類では植物病原菌やアーバスキュラー菌根菌が増加し、菌類群集の構成も大きく変化していた。こうした環境では外来植物の種数、被度、バイオマスが周辺自然地より高く、建設による攪乱で生じた空間や持ち込まれた繁殖体が定着を助けると考えられた。特に在来植物の多様性低下が外来植物増加と最も強く関連し、生物学的抵抗性の低下が侵入の主要因であることが示された。さらに、本来は緯度によって異なる侵入メカニズムも鉄道沿線では攪乱の影響で弱まり、鉄道は外来植物の移動経路であるだけでなく、生態系そのものを改変して侵入を助長する重要な要因であることが示された。

<関連情報>

中国・ラオス鉄道沿線の鉄道駅周辺環境は、土壌菌類群集の変化や外来植物の優占度の増加と関連している Railway station habitats are associated with altered soil-fungal communities and higher alien plant dominance along the China-Laos Railway

Weitao Li, Yulong Zheng, Mark van Kleunen
Journal of Environmental Management  Available online: 2 July 2026
DOI:https://doi.org/10.1016/j.jenvman.2026.130380

Highlights

  • Railway construction reshaped soil physico-chemistry and fungal community assembly.
  • Disturbed station vegetation supported higher alien richness, cover and biomass.
  • Invasion mechanisms shifted from biotic exclusion to abiotic filtering latitudinally.
  • Native diversity loss was the strongest correlate of alien plant richness.

Abstract

Linear infrastructures are rapidly expanding worldwide, however, their ecological impacts remain poorly understood. Here we integrate vegetation, soil, and microbial surveys along a 495-km north-south transect of the recently opened China–Laos Railway to assess how railway construction influences above–belowground interactions and plant invasion dynamics, and how this depends on latitude and climate. Station habitats were characterized by lower soil organic carbon, total nitrogen, and moisture, as well as higher pH and altered C:N:P stoichiometry. These abiotic changes were accompanied by a pronounced reorganization of soil fungal communities, manifested as reduced beta diversity and increased richness of inferred plant pathogenic and arbuscular mycorrhizal fungal guilds. Disturbed vegetation near railway stations supported significantly greater alien plant richness, cover, and biomass compared to adjacent undisturbed vegetation. Moreover, the mean phylogenetic distance between alien and native species decreased with increasing latitude and remained higher in less disturbed sites, suggesting a transition from species interaction-driven exclusion in the tropics to environment-driven filtering in temperate regions. Structural equation modeling suggested that railway construction was associated with higher alien plant richness through multiple pathways, including shifts in soil nutrient stoichiometry, reduced native plant richness, and increased abundance of potential plant pathogenic fungi. Native plant richness exhibited the strongest negative relationship with alien plant richness. These findings suggest that railway-associated changes in environmental conditions and native community structure may influence patterns of plant invasion along railway corridors.

0911建設環境
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