桂林岩溶石山不同坡向灌丛植物多样性与土壤环境因子的关系

Relationship between plant diversity of shrubs and soil environmental factors along with slope aspects in karst hills of Guilin,Southwest China

该研究以桂林岩溶石山灌丛植物为对象,分析了灌丛群落物种丰富度指数、Shannon-Wiener指数和Pielou均匀度指数与土壤环境因子随坡向(阴坡-阳坡)梯度的变化规律。结果表明:(1)土壤含水量、土壤温度、土壤pH和土壤全磷均对植物群落类型及物种分布具有显著的影响,坡向对植物群落类型及物种分布具有极显著的影响;而土壤全氮、土壤有效氮和土壤有机碳对植物群落类型及物种分布则均无显著影响。(2)除Pielou均匀度指数在阴坡与阳坡差异不显著外,物种丰富度指数、Shannon-Wiener指数对不同坡向微生境均存在显著差异。其中,物种丰富度指数和Shannon-Wiener指数在不同坡向上均表现出相同的变化趋势,即阴坡大于阳坡。(3)除土壤pH值和土壤全磷含量差异不显著外,坡向对土壤含水量、土壤温度、土壤全氮含量、土壤有效氮含量、土壤有机碳含量均产生显著的影响。其中,土壤含水量、土壤有效氮含量、土壤有机碳含量则为阴坡大于阳坡,而土壤温度和土壤全氮含量为阴坡小于阳坡。(4)多元逐步回归分析表明,在阴坡上,各土壤环境因子对物种丰富度指数、Shannon-Wiener指数和Pielou均匀度指数作用均不显著;在阳坡上,物种丰富度指数与土壤温度呈显著负相关、与土壤有机碳含量呈显著正相关;Shannon-Wiener指数与土壤含水量和土壤有机碳含量呈显著正相关;Pielou均匀度指数与土壤有机碳含量呈显著正相关、与土壤全磷含量呈显著负相关。

In this study,we took the shrub plants of different slopes in Guilin karst hills as the research object.The relationship between species diversity(species richness index,Shannon-Wiener index and Pielou evenness index)of shrubs and soil environmental factors along with sloped(shady-sunny)gradients in the karst hills of Guilin were analyzed.Our results were as follows:(1)Soil water content,soil temperature,soil pH and soil total phosphorus have significant effects on plant community types and species distribution,and aspect has a very significant impact on plant communities and species distribution.Soil total nitrogen,soil available nitrogen and soil organic carbon had no significant effects on plant community types and species distribution.(2)Except for the Pielou evenness index,the difference between the shady slope and the sunny slope was not significant,species richness index and Shannon-Wiener index had significant differences in different slope microhabitats.Among them,the species richness index and the Shannon-Wiener index showed the same trend in different slopes,that is,the shady slope was larger than the sunny slope.(3)Except for the difference between soil pH and soil total phosphorus content was not significant,the slope aspect had a significant impact on soil water content,soil temperature,soil total nitrogen content,soil available nitrogen content,and soil organic carbon content.Among them,soil water content,soil available nitrogen and soil organic carbon content were shady slope greater than the sunny slope,while soil temperature and soil total nitrogen content were shady slope less than the sunny slope.(4)Multiple stepwise regression analysis showed that on the shady slope,effects of soil environmental factors on species richness index,Shannon-Wiener index and Pielou evenness index were not significant.On the sunny slope,there was a significantly negative correlation between species richness index and soil temperature,and a significantly positive correlation with soil organic carbon content;Shannon-Wiener index was significantly positively correlated with soil water content and soil organic carbon content;Pielou evenness index was significantly positively correlated with soil organic carbon content and negatively correlated with soil total phosphorus content.