藏北不同退化阶段高寒草甸植物群落特征与土壤养分特性  

Plant community composition and soil nutrient status of degraded alpine meadow sites in Northern Tibet

作　　者：彭艳 孙晶远 马素洁 王向涛 魏学红 孙磊 PENG Yan;SUN Jing-yuan;MA Su-jie;WANG Xiang-tao;WEI Xue-hong;SUN Lei(College of Life Science,Huazhong Normal University,Wuhan 430079,China;Resources&Environment College,Tibet Agricultural and Animal Husbandry University,Nyingchi 860000,China;Animal Science College,Tibet Agricultural and Animal Husbandry University,Nyingchi 860000,China)

机构地区：[1]华中师范大学生命科学学院,湖北武汉430079 [2]西藏农牧学院资源与环境学院,西藏林芝860000 [3]西藏农牧学院动物科学学院,西藏林芝860000

出　　处：《草业学报》2022年第8期49-60,共12页Acta Prataculturae Sinica

基　　金：国家重点研发计划(2016YFC0502003);国家自然科学基金项目(31760692);班戈畜牧,西藏草地保护与培育科研创新团队和西藏草业科学教学团队建设项目资助。

摘　　要：为探究藏北不同退化阶段高寒草甸的植物群落特征、土壤养分特性及其相关性,以那曲县那玛切村的轻度退化(lightly degraded,LD)、中度退化(moderately degraded,MD)和重度退化(severely degraded,SD)高寒草甸为研究对象,采用冗余分析(RDA)试图揭示不同退化阶段高寒草甸土壤环境因子与植被因子之间的关系。结果表明:1)研究区植物共有9科20属25种,莎草科、禾本科、菊科和蔷薇科植物适应性较强,不同退化草甸植被类型分别为高山嵩草+斑唇马先蒿,弱小火绒草+高山嵩草,二裂委陵菜+白苞筋骨草,其中高山嵩草是轻、中度退化草甸的优势种,不同退化阶段高寒草甸杂类草均占据重要地位,生活型以多年生草本为主。2)从轻度退化草甸到重度退化草甸,植物群落特征(地上生物量、高度、密度、频度、总盖度)整体呈递减趋势,且差异显著(P<0.05),Shannon-Wiener多样性指数、Margalef物种丰富度指数、Simpson优势度指数、Pielou均匀度指数随着退化加重呈降低的趋势。3)随退化程度加重,土壤有机质、速效氮、全氮、全磷、速效磷、速效钾、全钾均呈降低的趋势,土壤pH值逐步增加。4)不同退化草甸速效磷、全磷与物种多样性指数呈正相关关系,群落植被地上生物量与土壤全氮密切相关,且土壤环境因子含量对植被生长贡献率最高的分别为速效氮、有机质和pH。说明退化草甸的植被群落特征与土壤养分具有协同性,因此研究和治理西藏高寒草地退化必须重视土壤中氮磷元素的含量。This research investigated the community features,soil nutrient characteristics and their correlations in different degraded alpine meadows in Northern Tibet.Lightly degraded(LD),moderately degraded(MD)and severely degraded(SD)alpine meadow sites were selected for study and our research used a combination of field investigation,laboratory measurement,variance analysis and redundancy analysis to elucidate the relationships between vegetation ecological characteristics and soil environmental factors for these three different alpine meadow degradation stages in Northern Tibet.It was found that:1)There were 25 plant species from 20 genera and nine families present in the study area,and these were species with strong ecological adaptability,mainly from the in Cyperaceae,Poaceae,Asteraceae and Rosaceae families.Species associations commonly present across these alpine meadow sites included Kobresia pygmaea with Pedicularis longiflora,Leontopodium pusillum with K.pygmaea and Potentilla bifurca with Ajuga lupulina.Among these,K.pygmaea was the dominant species at LD and MD sites,although the functional groups were dominated by forbs.The perennial herb is the major vegetation component in Northern Tibet.2)The characteristics of the studied plant communities,including aboveground biomass,height,density,frequency and vegetation cover showed a decreasing trend from LD to SD(P<0.05).And the species Margalef index,Pielou index,Simpson index and Shannon-Wiener index of the LD sites had the highest values.3)With increasing alpine meadow degradation,organic matter,total nitrogen,total phosphorus,total potassium,available nitrogen,available phosphorus and available potassium all decreased,while pH increased.4)Species diversity index and the available phosphorus and total phosphorus across the series of degradation stages were significantly positively correlated.The aboveground biomass showed significantly positive correlations with total nitrogen.The factors contributing most strongly to vegetation growth in these alpine meadows a

关 键 词：退化草甸 群落特征 土壤养分特征 多样性指数 冗余分析 

分 类 号：S812[农业科学—草业科学]