退化高寒草地植物多样性和功能群组成与地上生产力的关系  

Linkages of plant diversity and functional groups to aboveground productivity upon alpine grassland degradation

作　　者：牛亚平 高晓霞 姚世庭 杨元合[1,2,3] 彭云峰 NIU Ya-Ping;GAO Xiao-Xia;YAO Shi-Ting;YANG Yuan-HePENG Yun-Feng(State Key Laboratory of Vegetation and Environmental Change,Institute of Botany,Chinese Academy of Sciences,Beijing 100093,China;China National Botanical Garden,Beijing 100093,China;University of Chinese Academy of Sciences,Beijing 100049,China;College of Agriculture and Animal Husbandry,Qinghai University,Xining 810016,China)

机构地区：[1]中国科学院植物研究所植被与环境变化国家重点实验室,北京100093 [2]国家植物园,北京100093 [3]中国科学院大学,北京100049 [4]青海大学农牧学院,西宁810016

出　　处：《植物生态学报》2025年第1期83-92,共10页Chinese Journal of Plant Ecology

基　　金：中国科学院战略性先导科技专项(A类)(XDA26020201)。

摘　　要：近半个世纪以来,气候变化和过度放牧等因素导致全球约50%的天然草地发生不同程度退化。草地退化显著改变了植物多样性和群落组成,进而影响生态系统生产力。然而,以往关于退化草地多样性与功能群组成对生产力的影响研究主要来自单点尺度,仍缺乏大尺度的观测证据。为此,该研究以青藏高原三江源退化高寒草地为研究对象,基于不同类型草地(高寒草原、高寒草甸和高寒沼泽化草甸)15个样点45条退化序列的标准化调查和采样,解析了高寒草地退化过程中植物多样性与功能群组成的变化及其与地上生产力的关联。结果显示,随退化程度的加剧,3种类型草地的物种丰富度、Shannon-Weiner多样性指数、Simpson多样性指数和Pielou均匀度指数整体上均呈“先上升后下降”的变化趋势;整体而言,群落中莎草科和禾本科植物盖度沿退化梯度显著降低,豆科植物盖度没有显著变化,而杂类草盖度均显著增加。进一步分析发现,退化过程中所有草地类型地上生产力的下降均主要与原生优势种盖度的降低有关,而植物多样性对生产力的影响较弱。以上结果表明,从植被的角度而言,原生群落中优势种盖度的减少而不是多样性的丧失是退化高寒草地植被生产力下降的主要原因,这一发现也为退化高寒草地恢复提供重要启示:植被恢复过程中优先恢复原生优势物种是提升退化草地生产力的有效途径。Aims During the past decades,about a half of the global grasslands have been degraded as the results of climate change and anthropogenic activities.Grassland degradation substantially alters plant diversity and community composition;however,it remains elusive how these changes link to ecosystem productivity across broad geographic scales.Methods Using a standardized survey from 45 grassland degradation sequences at 15 sites across three grassland types(i.e.,alpine steppe,alpine meadow and alpine swamp meadow)on the Qingzang Plateau,we aim to explore changes in plant diversity and functional groups upon grassland degradation and their linkages with aboveground net primary productivity(ANPP).Important findings Across the three grassland types,species richness,Shannon-Weiner diversity index,Simpson diversity index and Pielou evenness index all exhibited a first increase and then decrease pattern as degradation intensified.The coverage of sedge and grass declined,but legume coverage showed no significant changes and forb coverage increased along the degradation gradient.Mixed-effects models showed that degradation-induced change in ANPP was mainly associated with changes in coverage of original dominant species but minimally influenced by plant diversity for all grassland types.These results indicate that the degradation-induced productivity reduction is caused by the decline in dominant species rather than losses of plantdiversity.The findings mentioned above provide important clues for alpine grassland restoration:restoringdominant species would be an effective approach for boosting ecosystem productivity in degraded grasslands onthe Qingzang Plateau.

关 键 词：植物多样性 功能群组成 植被生产力 草地退化 高寒草地 

分 类 号：S81[农业科学—畜牧学]