黔西北黄杉群落物种多样性的海拔梯度格局

Altitudinal Pattern of Species Diversity of Pseudotsuga sinensis Communty in Northwestern Guizhou,China

研究海拔高度对黄杉群落物种多样性的影响,为珍稀濒危植物黄杉的保育和喀斯特山地生物多样性的保护提供科学依据。采用样地法调查不同海拔梯度黄杉群落的物种组成,分析其区系特征,研究黄杉群落物种多样性的海拔梯度格局和维持机制。样地内共记录种子植物50科95属124种,群落内植物属的地理成分复杂、多样,具有明显的温带性质;随着海拔的增加,黄杉群落灌木层和草本层的物种丰富度指数S、Shannon-Wiener多样性指数H、Simpson优势度指数D和Pielou均匀度指数J均呈单峰格局变化趋势,且在不同海拔上存在显著差异(P<0.05),但灌木层物种的Pielou均匀度指数不显著(P≥0.05);相邻海拔间的β多样性指数变化趋势不同,灌木层物种的Sørenson指数呈双峰曲线,草本层物种的Sørenson指数呈单峰曲线,灌木层和草本层的Cody指数均呈单峰曲线;随着海拔高差的增加,黄杉群落草本层物种的Sørenson指数逐渐减小,其它均无明显变化规律。整体来看,相对海拔导致的水热条件差异是影响喀斯特山地物种多样性垂直分布格局的主要因素,其中,中海拔地带黄杉群落的物种多样性最高,这对黄杉种质资源的保护和维持具有重要意义,同时对喀斯特山地植物群落的管理和生态系统稳定的维持也具有重要指导意义。

In order to provide a scientific basis for the conservation of Pseudotsuga sinensis community and the protection of Karst mountain biodiversity,the effects of altitude on the species diversity of P.sinensis community were studied.The species composition of different altitudinal gradients of P.sinensis community and the floristic characteristics were analyzed using the sampling survey method,to explore the altitudinal gradient pattern and maintenance mechanism of the species diversity of the P.sinensis community.There were 124 species of seed plants belonging to 95 genera,50 families in the sample plot.The geographical composition of plant genera in the community was complex and diverse,with obvious temperate properties.The species richness index,Shannon Wiener diversity index,Simpson dominance index and Pielou evenness index of shrub layer and herb layer all showed a single peak curve.Furthermore,on the altitudinal gradient,they presented significant difference,but the Pielou evenness index of shrub layer was not significant(P<0.05).The variation trend ofβdiversity index between adjacent altitudes was different,with Sørenson index of the shrub layer species showed a double peak curve,whereas that of the herb layer species with a single peak curve,and the Cody index of the shrub layer and the herb layer both showed a single peak curve.With the increase of altitude difference,the Sørenson index of herbaceous layer species gradually decreased,while the otherβdiversity indexes of the shrub layer and the herb layer presented no obvious change rule.On the whole,the difference in water and heat conditions caused by relative altitude was the main factor affecting the vertical distribution pattern of species diversity in karst mountains areas.Among them,the species diversity under P.sinensis forests in the middle altitude zone was the highest,which was of great significance for the protection and maintenance of germplasm resources of P.sinensis,and also had important guiding significance for the management of plant communities and the maintenance of ecosystem in karst mountains areas.