楚雄市西郊云南松林下草本优势种种间联结及环境解释

Interspecific Association and Environmental Interpretation of Dominant Herbaceous Species in Pinus yunnanensisForest in the Western Suburbs ofChuxiongCity

草本植物是森林生态系统重要组成部分。对楚雄市西郊云南松(Pinus yunnanensis)林下优势草本植物间的种间联结性及其与环境因子之间的关系进行探讨,旨在为该区域云南松林生态系统的结构和功能的维持提供参考。运用生态位宽度、生态位重叠值、方差比率法、卡方检验、联结系数和M.Godron稳定性测定对8种草本优势种间的相互关系进行综合分析;运用冗余分析(redundancy analysis,RDA)方法,探讨优势草本植物分布与环境因子的关系。结果表明,(1)多数草本优势种的生态位宽度较窄,仅云南裂稃草(Schizachyrium brevifolium)具有较大的生态位宽度,多数草本优势种之间存在较小的生态位重叠。(2)云南裂稃草属于发展性物种,其他7种物种均为衰退性物种。(3)草本优势种间的总体联结性表现为显著负联结,多数种对之间联结程度不显著;群落稳定性测定坐标值为(47.42,52.58),远离稳定坐标点(20,80)。(4)对草本层物种分布影响显著的环境因子为:土壤pH值、坡向、土壤有机质、土壤电导率和土壤全磷。以上研究表明该地区的草本优势种间独立性较强。草本群落整体处于不稳定状态,仍处于演替的早期阶段。在今后的森林管理活动中,可根据草本优势种的种间关系、生态位特征以及影响物种分布的环境因子对林下草本植物进行调控,维持和提升草本群落的稳定性。

Herbaceous plant is an important component of forest ecosystem.The interspecific associations of dominant herbaceous plants and the relationships between environmental factors and herbaceous plant communities were investigated in Pinus yunnanensis forest in the western suburbs of Chuxiong City,thereby providing basic information for maintaining the structure and function of forests ecosystem in the region.The relationship among8 dominantherbaceousspecies was comprehensively analyzed using niche width,niche overlap,variance ratio method,Chi-square test,connection coefficient,Spearman’s rank correlation coefficient and M.Godron stability analysis.The relationships between environmental factors and dominant herbaceous species were investigated by redundancy analysis(RDA).The results showed that,(1)most of the dominantherbaceousplants had narrow niche width,and Schizachyrium brevifolium(Sw)Nees ex Buse had a wider niche breadth than other species.The niche overlap of most dominant herbaceous species were low.(2)The aggression of Schizachyrium brevifolium(Sw)Nees ex Buse was the strongest,whereas the other seven dominantspecies were declining populations.(3)The overall interspecific associations were significantly negative associations among all thedominantherbaceous species,and the interspecific association was not significantly correlative in most of the speciespairs.The result for the community stability(47.42/52.58)was distinct to the value of 20/80.(4)By RDA analysis,soil pH,slope aspect,soil organic matter,soil electric conductivity and total phosphorus weresignificant factors affecting the distribution of herbaceous species.Based on the analyses mentioned above,we found that the herbaceous species were highly independent in our study area.The whole dominant herbaceous community was unstable,and the community was still in the early stage of succession.The structure ofherblayer can be adjusted according to interspecific association,niche characteristics,and environmental factors in future forest management activities,in order tomaintain and improve the stability of herbaceous plant community.