摘要
本研究以年楚河流域海拔3800~5100 m段的种子植物为对象,探究流域植物群落结构特征,分析物种多样性和系统发育多样性沿海拔梯度的分布格局及环境驱动机制。结果表明:研究区内主要群落类型为中亚早熟禾+短柄鹅观草+紫花针茅群落、高山嵩草+华扁穗草+蕨麻群落及砂生槐+白草群落,物种丰富度为5~28,均值为15.18±5.04,系统发育多样性指数(PD)为621.45~2315.96,平均值为1441.44±348.83。物种多样性与系统发育多样性均沿海拔呈单调递增格局。在65%的样方中,净谱系亲缘关系指数(NRI)和净最近种间亲缘关系指数(NTI)均大于0。影响物种多样性和系统发育多样性的主要土壤驱动因素为土壤总氮和水解性氮,其贡献率分别为23.4%和22.8%。在气候因素中,潜在蒸散量、年均温与物种多样性及系统发育多样性呈显著负相关,湿润指数与NRI和NTI呈显著负相关。海拔与纬度是影响物种丰富度及系统发育多样性指数的主要地理驱动因子。Mantel检验显示,物种β多样性与地理距离及海拔等环境因子呈显著正相关,而系统发育β多样性对地理距离的响应相对较弱。年楚河流域植物群落的构建受地理隔离和环境异质性的共同驱动,系统发育结构表现为明显的聚集,中高海拔带系统发育多样性指数较高,环境异质性对其具有更强的解释力,气候变化引发的干旱加剧可能会对该区域的植物多样性构成潜在的风险。
By investigating seed plants at an altitude range of 3800-5100 m in the Nyangchu River Valley,we examined plant community structure and the distribution patterns of species diversity and phylogenetic diversity along the altitudinal gradient,as well as the environmental factors driving these patterns.The results showed that there were three main community types,including the Poa litwinowiana+Elymus brevipes+Stipa purpurea community,the Carex parvula+Blysmus sinocompressus+Argentina anserina community,and the Sophora moorcroftiana+Pennisetum flaccidum community.Species richness varied from 5 to 28,averaging 15.18±5.04.The phylogenetic diversity index(PD)ranged from 621.45 to 2315.96,averaging 1441.44±348.83.The species and phylogenetic diversity monotonically increased with altitude.In 65%of the plots,both the net relatedness index(NRI)and net nearest taxa index(NTI)were greater than zero.The main soil drivers of species and phylogenetic diversity were total nitrogen and hydrolyzable nitrogen,with contribution rates of 23.4%and 22.8%,respectively.In terms of climatic drivers,potential evapotranspiration and mean annual temperature negatively correlated with species and phylogenetic diversity,while moisture negatively correlated with NRI and NTI.Altitude and latitude were the most significant geographical drivers of species richness and phylogenetic diversity.Results of the Mantel tests confirmed that speciesβ-diversity was significantly positively correlated with geographic distance and environmental factors such as altitude,while phylogeneticβ-diversity showed comparatively weaker correlations with geographic distance.Community assembly in the Nyangchu River Valley was jointly driven by geographical isolation and environmental heterogeneity.The phylogenetic structure had a clear clustering.Higher phylogenetic diversity was found in mid to high-altitude zones,with environmental heterogeneity showing higher explanatory power.Increasing drought induced by climate change would threaten plant diversity in this region.
作者
益西佳措
古桑群宗
赤列嘉措
拉多
YIXI Jiacuo;GUSANG Qunzong;CHILIE Jiacuo;LA duo(Provincial Level Station of Nagqu Mitika Wetland Ecosystem Observation and Research,Xizang University,Lhasa 850000,China;Lhasa Middle School of Xizang Autonomous Region,Lhasa 850000,China;Laboratory for Alpine Botany,School of Ecology and Environment,Xizang University,Lhasa 850000,China;Center for Carbon Neutrality in the Earth’s Third Pole,Xizang University,Lhasa 850000,China)
出处
《应用生态学报》
北大核心
2025年第8期2287-2296,共10页
Chinese Journal of Applied Ecology
基金
国家自然基金委联合基金项目(U20A2005)
2022年中央支持地方高校发展专项资金项目(藏财预指[2022]01号)
中央支持地方高校发展专项资金项目(藏财预指[2023]01号)资助。
关键词
物种多样性
系统发育多样性
系统发育结构
环境因子
年楚河流域
species diversity
phylogenetic diversity
phylogenetic structure
environmental factor
Nyangchu River Valley
