巴音布鲁克高寒草甸物种多样性与系统发育多样性沿海拔梯度分布格局及驱动因子

Species diversity and phylogenetic diversity in Bayinbrook alpine grasslands:elevation gradient distribution patterns and drivers

沿海拔梯度研究植物群落物种多样性和系统发育多样性可以明晰环境条件对群落构建的影响,可为深入了解群落构建机制提供帮助。选取巴音布鲁克高寒草甸为研究区,针对研究区植物群落物种多样性和系统发育多样性随海拔梯度变化趋势及其环境驱动因子开展研究,探究在群落构建中物种共存及多样性维持过程中环境因子的影响程度。结果表明:1)随海拔升高,群落Shannon-Wiener多样性指数与Simpson丰富度指数均呈单峰变化趋势,峰值分别在2400和2600 m处;群落Pielou均匀度指数呈逐渐下降趋势;系统发育多样性指数(PD)整体呈下降趋势,系统发育结构逐渐由分散状态转变为聚集状态。2)系统发育结构指数里净最近种间亲缘关系指数(NTI)和净谱系亲缘关系指数(NRI)与物种多样性指数均呈显著负相关关系(P<0.05),PD指数与物种多样性指数均呈显著正相关(P<0.05)。3)各土壤因子对不同多样性指数的影响程度不同,其中铵态氮含量是影响物种多样性和系统发育指数的主要因子,全钾含量次之;土壤全氮含量对NTI存在显著影响(P<0.05),全钾含量对NRI存在显著影响(P<0.05),全磷对PD指数存在显著影响(P<0.05),pH对物种多样性指数存在显著影响(P<0.01)。沿海拔梯度群落物种多样性和系统发育多样性、系统发育结构之间相互关联,受环境因子的影响,两者在海拔梯度上呈现不同的响应策略。

Coastal gradient studies of plant community species diversity and phylogenetic diversity can clarify the influence of environmental conditions on community construction and can provide insight into community construction mechanisms.This research studied the trends in plant community species diversity and phylogenetic diversity and their environmental drivers along an altitude gradient from 2200-3000 m.a.s.l.in Bayinbrook alpine meadow,to explore the influence of environmental factors in the processes of species coexistence and diversity maintenance in community construction.It was found that:1)With increase in altitude,the Shannon-Wiener diversity index and Simpson diversity index of the community showed a unimodal change trend,with peaks at 2400 and 2600 m,respectively.The community Pielou uniformity index showed a gradual downward trend;the PD index showed a downward trend as a whole,and the phylogenetic structure gradually changed from a dispersed status to an aggregated status.2)The phylogenetic structure indexes NTI and NRI showed a significant negative correlation with the species diversity index(P<0.05),and the PD index and species diversity index showed a significant positive correlation(P<0.05).3)The degree of influence of various soil factors on different diversity indices differed;NH4+-N content was the main factor affecting species diversity and phylogenetic indexes,followed by total potassium content.Soil total nitrogen content had significant effects on NTI(P<0.05).NRI was significantly affected by total potassium content(P<0.05),the phylogenetic impact index PD was significantly affected by total phosphorus(P<0.05),and species diversity index was significantly affected by pH(P<0.01).The species diversity and phylogenetic diversity of coastal altitude gradient communities are interrelated,and the two show different response strategies along the altitude gradient due to the influence of environmental factors.