To understand the distribution pattern and influencing factors of plant community and diversity along the altitude gradient, we examined plant community types, plant diversity and phylogenetic diversity of mountain steppe in Luoshan, Ningxia, and analyzed the relationship between the plant community and its diversity and environmental driving factors. The results showed that the main community types in the mountain steppe were Asterothamnus centraliasiaticus community, Caragana tibetica community, Convolvulus tragacanthoides community, Stipa bungeana community, Stipa breviflora＋Ajania achilloides community, Artemisia frigida community, Roegneria alashanica＋S. breviflora＋Hedysarum polybotrys community, S. breviflora＋Stipa grandis community, S. grandis＋S. bungeana community, Cyperus glomeratus community, S. grandis community and Carex aridula community. The distribution of mountain steppe community was mainly affected by altitude, soil alkali-hydrolyzed nitrogen, water content, available potassium, silt and organic matter contents, with altitude and soil water content having the greatest effects (P<0.01). The Patrick index and phylogenetic diversity index (PD) of plant community showed an increasing trend with the altitude increase, the Shannon index and Pielou index showed a unimodal trend, and the phylogene-tic structure gradually changed from aggregation to dispersion. There was a significant positive correlation between species diversity index and PD index. Shannon index was negatively correlated with net relatedness index (NRI). Plant species diversity and phylogenetic diversity of mountain steppe were mainly affected by soil water content, available potassium, total nitrogen, silt and sand contents. NTI was significantly affected by altitude, while the NRI index was significantly affected by soil silt content.
为了解山地草原植物群落及其多样性沿海拔梯度的分布格局和影响因素,本文研究宁夏罗山山地草原植物群落类型、植物多样性、系统发育多样性,分析植物群落及其多样性与环境驱动因子的相互关系。结果表明: 研究区内山地草原主要群落类型为中亚紫菀木群落、毛刺锦鸡儿群落、刺旋花群落、长芒草群落、短花针茅+蓍状亚菊群落、冷蒿群落、阿拉善鹅观草＋短花针茅＋宽叶多序岩黄芪群落、短花针茅+大针茅群落、大针茅＋长芒草群落、莎草群落、大针茅群落和干生薹草群落。山地草原群落的分布主要受海拔、土壤碱解氮、含水量、速效钾、粉粒和有机质含量的影响,并以海拔和土壤含水量的影响最大(P<0.01);随着海拔上升,群落Patrick指数和系统发育多样性指数(PD)呈递增趋势,Shannon指数和Pielou指数呈单峰变化趋势,系统发育结构由聚集逐渐转变为分散。山地草原物种多样性指数与PD指数均呈显著正相关;Shannon指数与净谱系亲缘关系指数(NRI)呈显著负相关。山地草原植物物种多样性和系统发育多样性主要受土壤含水量、速效钾、全氮、粉粒和砂粒含量影响,海拔显著影响净最近种间亲缘关系指数(NTI),土壤粉粒含量显著影响NRI指数。.
Keywords: community classification; mountain grassland; phylogenetic diversity; soil factor; species diversity.