高寒草甸退化过程中群落生产力和物种多样性的非线性响应机制研究  

Nonlinear responses of productivity and diversity of alpine meadow communities to degradation

作　　者：陈宁[1,2] 张扬建 朱军涛[1] 李军祥 刘瑶杰[1,2] 俎佳星[1,2] 丛楠[1] 黄珂 王荔 CHEN Ning1,2,ZHANG Yang-Jian1,3,4,ZHU Jun-Tao1,LI Jun-Xiang5,LIU Yao-Jie1,2,ZU Jia-Xing1,2,CONG Nan1,HUANG Ke1,WANG Li5(1 Lhasa Plateau Ecosystem Research Station, Key Laboratory of Ecosystem Network Observation and Modeling, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing 100101 China2 University of Chinese Academy of Sciences, Beijing 100190, China3 CAS Center for Excellence in Tibetan Plateau Earth Sciences, Beijing 100101, China4 College of Resources and Environment, University of Chinese Academy of Sciences, Beijing 100190, China5 Peking University Shenzhen Graduate School, Shenzhen 518055, Chin)

机构地区：[1]中国科学院地理科学与资源研究所生态系统网络观测与模拟重点实验室拉萨高原生态试验站,北京100101 [2]中国科学院大学,北京100190 [3]中国科学院青藏高原地球科学卓越创新中心,北京100101 [4]中国科学院大学资源与环境学院,北京100190 [5]北京大学深圳研究生院,深圳518055

出　　处：《植物生态学报》2018年第1期50-65,共16页Chinese Journal of Plant Ecology

基　　金：国家重点研发计划(2016YFC0501802和2017YFA0604802);国家自然科学基金(41571195和41501103)~~

摘　　要：为了阐释青藏高原高寒草甸退化的关键生态过程,该研究依托藏北高原草地生态系统研究站(那曲站),设置不同退化梯度实验,即对照、轻度退化、中度退化、重度退化和极度退化5个梯度,探究群落生产力和物种多样性对不同退化强度的响应机制。结果表明:1)随着退化程度不断加剧,地上生物量呈现线性或非线性增加趋势,在重度退化处理下,地上生物量显著高于对照32.3%,其中高山嵩草(Kobresia pygmaea)地上生物量呈非线性下降趋势,而矮火绒草(Leontopodium nanum)地上生物量呈非线性增加趋势;2)与地上生物量的响应模式相反,随着退化程度加剧,地下生物量与总生物量均呈现非线性降低趋势;3)高寒草甸退化过程中,物种辛普森指数、丰富度指数、香农多样性指数和均匀度指数均呈现非线性上升趋势。结构等式方程结果表明,土壤碳含量和体积含水量与地下生物量均呈现显著的正相关关系。土壤碳含量、体积含水量和砾石质量比对地上生物量无显著影响,土壤碳、氮含量与物种多样性指数呈现显著的负相关关系。研究认为地上生产力的变化不能很好地指示草地的退化程度,建议今后研究应以可食性牧草和毒杂草等植物功能群的变化来衡量草地退化。Aims The alpine meadow degradation could have profound effects on the grassland productivity. The aim of our study is to clarify the dynamic response of community productivity and species diversity in the process of alpine meadow degradation. Methods In the Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Northern Tibetan Grassland Ecosystem Research Station （Nagqu station）, we conducted stages experiments with multiple degradation levels： control, mild degraded meadow, moderate degraded meadow, severe degraded meadow and serious sandy meadow. Important findings The response of aboveground biomass to alpine meadow degradation showed a linear or nonlinear increased response patterns, but the belowground biomass and total biomass decreased nonlinearly. As observed in measurement of aboveground biomass, Margalef index, Simpson index, Shannon-Wiener index and Pielou evenness index also exhibit a nonlinear increased response to degradation. The results of structural equation models showed that belowground biomass has a positive relationship with soil carbon content （p 〈 0.05） and volume water content （p 〈 0.1）. However, soil nutrient and soil physical properties had no significant impact on aboveground biomass （p 〈 0.1）. Compared with soil physical properties, soil nutrition is an important factor influencing the diversity index. In our study, the nonlinear responses of productivity and diversity of alpine meadow were described by using the multiple levels of degradation in space. The results suggested that aboveground productivity cannot interpret the degree of degradation of alpine meadow, and by contrast, alpine meadow degradation should be measured by the change of plant functional groups, such as edible grasses and poisonous forbs.

关 键 词：高寒草甸 退化梯度 物种多样性 生产力 非线性响应 

分 类 号：S812[农业科学—草业科学]