青藏高原高寒灌丛草甸和草原化草甸CO<sub>2</sub>通量动态及其限制因子

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青藏高原高寒灌丛草甸和草原化草甸CO₂通量动态及其限制因子

柴曦^1,³,李英年²,段呈^1,³,张涛⁴,宗宁¹,石培礼^1,^3,^*(

),何永涛^1,³,张宪洲^1,³

CO₂ flux dynamics and its limiting factors in the alpine shrub-meadow and steppe-meadow on the Qinghai-Xizang Plateau

CHAI Xi^1,³,LI Ying-Nian²,DUAN Cheng^1,³,ZHANG Tao⁴,ZONG Ning¹,SHI Pei-Li^1,^3,^*(

),HE Yong-Tao^1,³,ZHANG Xian-Zhou^1,³

图5. 高寒灌丛草甸和草原化草甸2004-2008年16天平均生物和环境影响因子(气温, T_a, ℃; 5 cm土壤温度, T_s, ℃; 5 cm土壤含水量, SWC, m³·m^-3; 降水量PPT, mm; 光合有效辐射, PAR, μmol·m^-2·s^-1; 归一化植被指数, NDVI)对CO₂通量(净初级生产力, NEP, g C·m^-2·d^-1; 总初级生产力, GPP, g C·m^-2·d^-1; 生态系统呼吸, R_e, g C·m^-2·d^-1)的结构方程模型图。A, C, E, 海北高寒灌丛草甸。B, D, F, 当雄高寒草原化草甸。A, B, C, D, 生长季节。E, F, 非生长季。黑色箭头是正相关, 灰色箭头是负相关, 实线箭头表示p ≤ 0.05, 虚线箭头表示p > 0.05, 箭头上的数字代表通径系数, 箭头的宽窄代表通径系数的大小。

Fig. 5. Path diagrams illustrating the effects of 16-day mean biotic and abiotic factors (air temperature, T_a, ℃; soil temperature at the depth of 5 cm, T_s, ℃; soil water content at the depth of 5 cm, SWC, m³·m^-3; precipitation, PPT, mm; photosynthetically active radiation, PAR, μmol·m^-2·s^-1; normalized difference vegetation index, NDVI) on 16-day mean CO₂ fluxes (net ecosystem productivity, NEP, g C·m^-2·d^-1, gross primary productivity, GPP, g C·m^-2·d^-1 and ecosystem respiration, R_e, g C·m^-2·d^-1) during the growing season (A-D) and non-growing season (E, F) from 2004-2008 in the alpine shrub-meadow (A, C, E) and steppe-meadow (B, D, F). The grey solid arrows represent significantly negative correlation and the black solid arrows denote significantly positive correlation (p ≤ 0.05). The dashed arrows represent non-significantly correlation (p > 0.05). Data on the arrows are the standardized SEM coefficients. The thickness of the arrows reflects the magnitude of the standardized SEM coefficient.