樹皮が熱帯林の倒木分解に関わる菌類群集を左右する(Bark Shapes Fungal Communities During Tropical Tree Decomposition)

2026-10-09 中国科学院(CAS)

中国科学院西双版納熱帯植物園(XTBG)の研究チームは、熱帯林における枯死木の分解過程で、樹皮が木材に定着する菌類群集の構成や形成過程を左右することを明らかにした。研究では、5種の熱帯樹木から採取した丸太を用い、樹皮を残したものと除去したものを2年間比較した。菌類の遺伝子解析や微生物バイオマス測定、木材の化学分析を行った結果、樹皮がある場合は初期段階で白色腐朽菌を含む担子菌類が多くなり、樹皮を除去すると子嚢菌類の割合が高まることが分かった。一方、樹皮の有無は菌類と細菌を合わせた総バイオマスには直接的な影響を及ぼさなかった。また、分解の進行に伴い菌類のバイオマスは減少し、細菌は増加した。木材の質量減少には、リグニンやセルロースの分解、含水率も関係していた。本成果は、森林生態系における炭素・栄養塩循環や生物多様性の理解、森林の炭素動態評価の高度化に役立つ。

樹皮が熱帯林の倒木分解に関わる菌類群集を左右する(Bark Shapes Fungal Communities During Tropical Tree Decomposition)

Fungal community on tropical dead wood. (Image by Gbadamassi G.O. Dossa)

<関連情報>

樹皮の存在は熱帯林における菌類群集の構成を変化させ、菌類の多様性とバイオマスに様々な影響を与える Bark presence shifts fungal guild composition with varying effects on fungal diversity and biomass in a tropical forest

Jean Evans Israel Codjia, Busayo Joshua Babalola, Weiming Hu, Yun-Qiang Yang, Sewanou H Honfo, Ekananda Paudel, Douglas Schaefer, Kun-Fang Cao, Jian-Chu Xu, Yong-Ping Yang,…

ISME Communications  Published:06 September 2026

DOI:https://doi.org/10.1093/ismeco/ycag258

Abstract

Bark influences wood decomposition, but the mechanisms are unclear. We investigated fungal community composition, microbial biomass, and wood physicochemical condition during a wood decomposition experiment. We carried out a 2-year common garden experiment in a tropical seasonal rainforest, China, with logs from five tree species, comparing intact-bark versus bark-removed treatments over 0, 18, and 24 months of field exposure. We sequenced wood-inhabiting fungi, measured microbial biomass, and assessed wood chemical properties over time. We anticipated bark presence would alter fungal community composition and increase diversity, decay types, and microbial biomass. Wood with bark-removed had a higher relative abundance of Ascomycota, whereas bark presence fostered Basidiomycota. Soft rot fungi showed the highest relative abundance, followed by white rot fungi and brown rot fungi. However, bark presence was associated with higher relative abundance of white rot fungi, during early decay. Wood chemical properties and moisture (water content) availability, were correlated with the dominance of saprotrophs, rather than bark status. Despite compositional shifts, bark status did not influence fungal alpha diversity at the bark effects level. Bark status also did not directly influence fungal and bacterial biomass. Microbial biomass dynamics were instead linked to changes in wood physicochemical properties as decomposition progressed. Fungal community turnover dominated over time in bark-removed treatments, while bark presence redirected community assembly toward nestedness at the advanced decay stages. Overall, bark presence was linked with a shift toward more deterministic, habitat-filtered microbial community assembly, suggesting a multi-guild, multi-factor framework to predict bark effects on wood decay in forests.

1304森林環境
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