摘要
高寒草地是青藏高原生态系统的主体,高寒草地物种多样性和生物量沿海拔梯度的空间分布格局在气候变化及人为干扰的双重影响下已发生重大变化。为明晰海拔对物种多样性和生物量的影响,以藏北地区那曲市罗玛镇高寒草地为研究对象,于2018年8月采用样方调查法对不同海拔梯度高寒草地植物高度、盖度、地上生物量及物种多样性沿海拔变化进行调查和统计分析,探讨藏北高寒草地物种多样性和地上生物量在海拔上的变化规律及二者的关系。研究表明:(1)植物盖度和地上生物量分别由海拔4 600 m的89.0%和64.7 g·m^-2降至4 800 m的67.3%和41.8 g·m^-2,即植物盖度和地上生物量随海拔的升高呈线性降低的趋势;(2)不同海拔梯度间植物物种组成存在较大差异,高海拔段中旱生禾本科植物逐渐被耐寒喜湿植物取代;(3)物种丰富度和Shannon-Wiener指数沿海拔呈单峰分布格局,而E.Pielou均匀度指数则呈U型分布格局;(4)物种丰富度和Shannon-Wiener指数与地上生物量呈负二次函数关系;地上生物量与土壤温度呈指数增长趋势,与土壤湿度呈指数降低的趋势。研究结果初步揭示了藏北高原高寒草地不同海拔梯度物种多样性及其生物量的垂直分布差异,以及不同海拔梯度间水热组合差异对物种多样性及其生物量的影响。
Alpine grassland is an important component of the ecosystem of Qinghai-Tibet Plateau, however, significant changes have occurred on species diversity and biomass of grassland across the elevation gradient in this region due to anthropogenic interference and climate change. Consequently, a field survey was conducted in a representative mountain in Luoma Town, Naqu City, northern Tibetan Plateau, in August 2018, to discover the impact of elevation gradient on species diversity and above-ground biomass and reveal their relationship with alpine grassland communities by exploring the quadrat method. Results showed that the plant coverage and above-ground biomass of alpine grassland decreased linearly with the increase of altitude observation of two variants decreased from 89.0% and 64.7 g·m^-2 at 4 600 m to 67.3% and 41.8 g·m^-2 at 4 800 m, respectively. Furthermore, remarkable differences existed among species composition of various elevation gradient and the xerophytic grasses species gradually replaced by the hygrophilous plants in the high elevation gradient. Additionally, both of the index of species richness and Shannon-Wiener was presented in an unimodal distribution pattern with the increase of altitude, whirst the E.Pielou index exhibited a “U-shaped” pattern. Last but not least, negative quadratic relationship existed between the above-ground biomass and the index of species richness and Shannon-Wiener, while, with the augment of elevation gradient, above-ground biomass exhibited a trend of increase and decrease with soil temperature and soil moisture, respectively. The findings of our study indicate that significant difference of vertical distribution of species diversity and biomass in north Tibetan Plateau as affected by elevation gradient, and moreover, there is important impact of temperature and moisture of soil on species diversity and biomass with different altitude.
作者
吴红宝
水宏伟
胡国铮
王学霞
干珠扎布
严俊
何世丞
谢文栋
高清竹
WU Hongbao;SHUI Hongwei;HU Guozheng;WANG Xuexia;H. Ganjurjiav;YAN Jun;HE Shicheng;XIE Wendong;GAO Qingzhu(Institute of Environment and Sustainable Development in Agriculture, Chinese Academy of Agricultural Sciences, Beijing 100081, China;College of Territorial Resources and Tourism, Anhui Normal University, Wuhu 241000, China;Naqu Grassland Station, Naqu Tibet Autonomous Region, Naqu 852000, China)
出处
《生态环境学报》
CSCD
北大核心
2019年第6期1071-1079,共9页
Ecology and Environmental Sciences
基金
国家重点研发计划课题(2016YFC0502003)
国家自然科学基金项目(31600366
31570484)
中央级公益性科研院所基本科研业务费专项基金项目(BSRF201713)
关键词
海拔梯度
物种多样性
生物量
高寒草地
elevation gradient
species diversity
biomass
alpine grassland
