关键词：
雪被;高山草地;土壤物理性质;土壤化学性质;叶片性状;株高;开花物候
摘 要：
季节性积雪综合影响着高山草地生态系统的结构与功能,以及植物不同水平对环境异质性响应的复杂性.本研究利用山脊风成的自然积雪梯度,首先对比高山草地不同处理之间的土壤环境因子,发现土壤含水量深雪覆盖处理显著较高.全氮、全磷和有机碳含量并无显著变化,而有效磷、微生物生物量碳(microbial biomass carbon, MBC)和微生物生物量氮(microbial biomass nitrogen, MBN)在不同积雪处理下均有显著差异且在生长旺季最低.高山草地植物性状对积雪厚度处理下的响应,高原毛茛(Ranunculus tanguticus)仅有单叶质量(individual leafmass, ILM)无显著差异.紫罗兰报春(Primula purdomii)在厚雪地段的ILM显著大于浅雪,而甘肃马先蒿(Pedicularis kansuensis)的表现却相反;高原毛茛在浅雪地段的ILM、株高(plant height, PH)均显著高于深雪.中期开花的长叶火绒草(Leontopodium longifolium)和羊茅(Festuca ovina)在厚雪地段具有更大的比叶面积(specific leaf area, SLA).矮生嵩草(Kobresia humilis)在浅雪地段具有显著更高的SLA、单叶面积(individual leafarea, ILA)和PH.晚期开花的华丽龙胆(Gentiana sino-ornata)的变化类似矮生嵩草;星状雪兔子(Saussurea stella)的单叶重量和大小有地段性差异.功能群水平上雪被厚度仅对植物的株高有显著影响,不同开花物候对叶片性状和PH均有极显著的影响.最后明确了植物性状与环境因子之间的相关性,早花植物的SLA和PH均与pH负相关,SLA与有机碳、全氮和砂粒含量均负相关.中期开花植物的SLA与pH、砂粒含量均正相关,而与全磷负相关;株高与有机碳、全氮和全磷均负相关.不同开花期功能群植物的比叶面积与株高均正相关.植物性状响应雪被厚度变化的物种及开花物候功能群特异性反映了高山草地植物适应环境变化及其异质性的生存策略,在高山草地草场维护与管理中,需要合理配比草种,以保证畜牧业的可持续发展.此结论在高寒工程实践的生态修复中也具有一定的应用价值.
作 者：
WANG Jinniu;ZHOU Tianyang;GAO Jing;ZHOU Haiyan;DU Wentao;Chengdu Institute of Biology, Chinese Academy of Sciences;State Key Laboratory of Cryospheric Science, Northwest Institute of Eco-Environment and Resources,Chinese Academy Sciences;University of Chinese Academy of Sciences;School of Ecological and Environmental Sciences, East China Normal University;NeiJiang Academy of Agricultural Sciences;
单 位：
WANG Jinniu%ZHOU Tianyang%GAO Jing%ZHOU Haiyan%DU Wentao%Chengdu Institute of Biology, Chinese Academy of Sciences%State Key Laboratory of Cryospheric Science, Northwest Institute of Eco-Environment and Resources,Chinese Academy Sciences%University of Chinese Academy of Sciences%School of Ecological and Environmental Sciences, East China Normal University%NeiJiang Academy of Agricultural Sciences
关键词：
snow cover;;alpine meadows;;soil physical properties;;soil chemical properties;;leaf trait;;plant height;;flowering phenology
摘 要：
Seasonal snow cover is a major factor influencing the structure and function of alpine meadows. It also affects the response of alpine plants to environmental heterogeneity at different levels. We studied the effect of a depth gradient of natural snow on the vegetation in an alpine meadow of Kaka Mountain. Firstly, we measured how soil environmental factors varied under different snow depths. Soil water content under deep snow cover was higher than under shallow snow cover.There were significant differences in total nitrogen content, total phosphorus content, and organic carbon content under deep snow and under shallow snow. The soil particle size also differed under deep or shallow snow, both in the early growing season and in mid-season. By comparison the response of plant leaf traits and height in an alpine meadow to different depths of snow cover, it indicates that Primula purdomii had greater ILM(individual leaf mass) and less SLA under deep snow cover significantly, but Pedicularis kansuensis showed no significant differences of all leaf traits and plant height between different snow cover treatments. Ranunculus tanguticus had greater ILM and plant height but less SLA under shallow snow cover than under deep snow cover. The mid-season flowering species, Leontopodium leontopodioides and Festuca ovina had greater specific leaf area(SLA) under deep snow cover, but Kobresia humilis had better SLA, ILA(individual leaf area) and plant height under shallow snow cover. The later flowering Gentiana sino-ornata indicated similar variation with medium flowering Kobresia humilis. Both ILM and ILA of Saussurea stella were significantly greater under shallow snow cover than deep snow cover. At functional group level, snow depth showed significant effects only on plant height while flowering phenology had significant effects on leaf traits and plant height. For early flowering plants, SLA and plant height were negatively correlated with pH, and between SLA was also negatively correlated with organic carbon, total nitrogen, and sand particle content. For mid-season flowering plants, SLA was positively correlated with pH and sand particle content, and negatively correlated with total phosphorus content. The plant height of mid-season flowering plants was negatively correlated with organic carbon content, total nitrogen content, and total phosphorus content. There was a significant relationship between SLA and plant height in all the different flowering functional groups. The species-and flowering phenology functional-specific response of plant traits on snow depth indicated the survival strategy from different plants in alpine meadows for adapting to environmental change. For the maintenance and management of alpine meadow, it is essential to select appropriate grass cultivars, which can ensure sustainable development of husbandry.
