永久凍土崩壊研究がチベット高原の生態系保全に寄与（Permafrost Collapse Study Helps Preserve Qinghai-Tibet Plateau Ecosystem）

2025-12-10 中国科学院（CAS）

＜関連情報＞

• https://english.cas.cn/newsroom/cas_media/202512/t20251215_1137068.shtml
• https://www.sciencedirect.com/science/article/pii/S0341816225009944

永久凍土の崩壊は青海チベット高原の微地形の変化を通じて高山生態系の発達を変化させる Permafrost collapse alters alpine ecosystem development via microtopographic modification on the Qinghai-Tibet Plateau

Xinyu Men, Ziteng Fu, Lili Zeng, Luyang Wang, Wenyan Du, Siru Gao, Gaosen Zhang, Guanli Jiang, Qingbai Wu
CATENA  Available online: 26 November 2025
DOI:https://doi.org/10.1016/j.catena.2025.109692

Graphical abstract

Highlights

• Permafrost collapse reshapes microtopography and re-sorts soil texture and moisture.
• Slumps redistribute carbon and nitrogen, increase bulk density and surface gravel.
• Vegetation shifts toward alpine swamp meadow on low-lying disturbed ground.
• Carbon uptake declines: ∼80 % in exposed zones and ∼25 % in other disturbed areas.
• Path analysis shows texture − moisture − substrate − vegetation − carbon uptake.

Abstract

Thermokarst landforms, particularly retrogressive thaw slumps (RTS), are proliferating across the Qinghai-Tibet Plateau (QTP), yet their ecosystem consequences remain poorly constrained. We integrated vegetation surveys, soil physicochemical analyses, and static-chamber CO₂ flux measurements across four representative RTS and four surface types (control check (CK), disturbed ground (DG), vegetated raft (VR), and exposed (EX)) to test how slump-induced microtopography governs ecosystem development. RTS increased soil bulk density and re-sorted particles, altering near-surface moisture and redistributing substrates (soil organic carbon, SOC; alkali-hydrolyzable nitrogen). At 0–15 cm, fine particles increased in disturbed ground (+23.4 %) but decreased in exposed areas (−58.7 %), where gravel increased by approximately 347.1 % (p ≤ 0.05); soil bulk density rose most in exposed areas (+27.6 %); soil moisture increased in vegetated rafts (+44.4 %) but declined in exposed areas (−8%). These edaphic shifts favored hygrophilous assemblages (Kobresia royleana), redirecting communities from alpine meadow toward swamp meadow on disturbed ground. However, functional recovery lagged structural change: gross primary productivity (GPP) declined by ∼80 % in exposed and remained ∼25 % lower in disturbed ground and vegetated raft despite substantial vegetation cover. SOC and alkali-hydrolyzable nitrogen densities were tightly coupled (R² = 0.92, p ≤ 0.001) and concentrated in surface soils. Partial least squares path modeling identified a dominant pathway from texture through moisture, substrate, and vegetation to GPP, in which vegetation exerted the strongest direct control on GPP and slump age provided a secondary direct effect. Overall, permafrost collapse accelerates ecosystem development via altered microtopography, expediting shifts toward hygrophilous communities while temporarily depressing carbon fixation until soils and vegetation stabilize. Incorporating patch-scale heterogeneity and slump age is therefore essential for forecasting QTP carbon dynamics.