放牧对藏北紫花针茅高寒草原植物群落特征的影响  

Effect of grazing on community characteristics and species diversity of Stipa purpurea alpine grassland in Northern Tibet

作　　者：段敏杰[1,2] 高清竹[1,2] 万运帆[1,2] 李玉娥[1,2] 郭亚奇[1,2] 旦久罗布 洛桑加措 

机构地区：[1]中国农业科学院农业环境与可持续发展研究所,北京100081 [2]农业部农业环境与气候变化重点实验室,北京100081 [3]西藏自治区那曲地区草原站,那曲852100

出　　处：《生态学报》2010年第14期3892-3900,共9页Acta Ecologica Sinica

基　　金：国家自然科学基金资助项目(30800142;40775062);国家自然科学基金资助项目(40971132);国家科技支撑计划项目(2007BAC03A06);西藏那曲地区与中国农业科学院合作资助项目

摘　　要：基于放牧试验,研究了不同放牧强度下藏北地区紫花针茅(Stipa purpurea)高寒草原植物群落特征的变化规律。结果表明,随着放牧强度的增强,植物群落盖度、地上生物量均呈现显著降低的趋势;紫花针茅等禾草类植物的重要值逐渐降低,莎草类中青藏苔草(Carex moorcroftii)、牲畜不喜食的杂类草及有毒有害植物均有增加的趋势;如果持续过度放牧,植物群落表现出由紫花针茅等禾草为建群种的草地型向青藏苔草(Carex moorcroftii)、杂类草(Herbarum variarum)草地型过度的趋势;在中度放牧强度下,紫花针茅高寒草原α物种多样性达到最高水平,而继续增强放牧强度,则造成各项指标的迅速降低。Alpine grassland is widely distributed in Northern Tibet. Stipa purpurea alpine grassland is one of the most important and representative meadow types in this area. In recent years,due to global warming and human activities such as overgrazing or excessive reclamation,the alpine grassland in Northern Tibet has undergone an accelerated and large-scale degradation. The grassland＇s productivity and biological diversity have decreased significantly and locally,this has also become a great obstacle to sustainable social,economic and ecological development. To investigate community characteristics and α diversity of Stipa purpurea alpine grassland under different grazing intensity in Northern Tibet is critical not only to the understanding of local degradation mechanisms,but also to the establishment of rational grassland management procedures,as required for continued healthy and sustainable development of alpine grassland. In our study,based on a grazing experiment in Northern Tibet grassland ecosystem,the community characteristics of Stipa purpurea alpine grassland under different grazing intensity were investigated. The research was conducted at the grazing experimental site of Anduo County,Naqu,Tibet Autonomous Region,at an average elevation over 4,500 m above sea level. The experiment included four different stocking rates：no grazing （0 head/hm^2,CK）,light grazing （2.395 head/hm^2,LG）,moderate grazing （3.593 head/hm^2,MG） and heavy grazing （5.988 head/hm^2,HG）. Based on the method of community investigation,community structure characteristics,such as species height,coverage and density were recorded. Aboveground biomass within areas of 0.5 m×0.5 m quadrat was also measured during the grass vigorous growth period. The species important value and summed dominance ratio were calculated by combining relative coverage,relative frequency and relative height. The species important value and summed dominance ratio were selected as comprehensive evaluation index of the importance of the species. The

关 键 词：放牧强度 群落特征 紫花针茅草原 Α多样性 中度干扰假说 

分 类 号：S812[农业科学—草业科学]