人类活动对高寒矮嵩草草甸的碳容管理分析

A study on carbon storage administration in alpine Kobresia humilis meadow in relation to influence of human activity

应用空间尺度代替时间尺度的方法研究青藏高原高寒矮嵩草草甸退化演替系列与人工草地恢复演替系列植物、土壤及植物-土壤系统有机碳分布及储量特征,以探讨该类型草地的适宜碳容管理方式。结果表明,随着草地退化程度的加剧,草地载畜能力逐渐下降;地上植物有机碳储量逐渐降低,最高值出现在禾草-矮嵩草草甸,为(145.9±6.7)g/m2;土壤有机碳储量和土壤-植物系统有机碳储量均先增高后降低,最高值均出现在矮嵩草草甸,其土壤及植物-土壤系统有机碳储量分别为(14 023.1±289.5)g/m2和(18 555.7±879.7)g/m2。对极度退化的高寒矮嵩草草甸(黑土滩-杂类草次生裸地)进行人工草地建植,随着建植年限的增加,地上植物、土壤及植物-土壤系统有机碳储量较建植前有不同程度提高。说明矮嵩草草甸是该退化演替系列中碳储能力、经济生产服务能力及生态系统稳定性配比最合理的阶段,是该退化演替系列的适宜碳容管理阶段;对黑土滩-杂类草次生裸地建植人工草地后围栏禁牧,可以明显提高草地的生态及生产服务能力,是该类草地的适宜碳容管理方式。

Alpine Kobresia meadow is the main vegetation type in the Qinghai-Tibetan Plateau.Grassland degradation is one of the prominent problems in this area.The distribution of organic carbon storage in plants,soil and the plant-soil systems,and variation characteristics of the organic carbon sinks in different grassland degradation succession stages were studied.A spatial series instead of time series method was used and the alpine Kobresia meadows degradation succession series were selected.They were gramineae-forbrich communities： A Kobresia humilis community,a normal Kobresia pygmae community phase,a K.pygmae community mattic epipedon crazing phase,a K.pygmae community mattic epipedon collapse phase and a herb-black soil stage.The organic carbon storage in aboveground plant parts significantly decreased from（145.9±6.7） g/m^2 to（84.9±5.5） g/m^2（P〈0.05）,while that of the plant underground parts of the K.pygmae community mattic epipedon crazing phase was the highest with a value of（3 011.6±114.3） g/m^2.The lowest was（121.6±14.9） g/m^2 in the herb-black soil stage.The normal K.pygmae community has the largest soil organic carbon storage capacity（16 805.94±856.5 g/m）2 which was higher than that of the herb-black soil stage（8 255.152±671.5 g/m^2） which had the lowest organic carbon storage in this kind of grassland degradation succession series.The highest organic carbon storage occurred in three phases,namely,normal K.humilis community,K.pygmae community phase and K.pygmae community mattic epipedon crazing phase,but there was no significant difference in the organic carbon storage capacities between these three phases.The alpine Kobresia meadows recovery series were artificial pasture vegetation succession series.After 14 years of artificial pasture cultivation,the plant organic carbon storage capacity in aboveground,underground and total plant system were 3.3 times,2.7 times and 2.9 times respectively of the herb-black soil stage,while the plant-soil system organic carbon storage capacity increased from（8 550.8±169.7） g/m^2 to（13 648.8±28.7） g/m^2.The K.humilis community is the optimum stage in alpine Kobresia meadows degradation succession series,because the plant-soil system in this stage retains the highest organic carbon storage,higher livestock loading and system stabilization,and it can be the optimum stage for carbon storage administration.It is an effective method to cultivate artificial pasture in herb-black soil stage for its obvious improvement of the organic carbon storage capabilities in plant,soil and plant-soil system,while the cultivated artificial grassland can also offer more edible forage for livestock.Choosing a proper stage and restoration methods to carry out the corresponding administrative management in the degradation ecosystem in alpine K.humilis meadow can result in the best ecological service ability and production ability.