喀斯特原生天坑植物群落空间格局特征——以云南沾益天坑为例

以云南沾益大毛寺原生天坑为例,获取坑内植物群落林木个体相对位置信息,进行角尺度、混交度、林层指数等林木空间结构参数与坑底植物群落空间格局分析,并运用点格局分析方法进行单个种群的空间分布特征以及不同种群间的空间关联性分析.结果表明: 大毛寺原生天坑坑底植物群落在空间分布上呈现随机分布,林木物种呈中度混交,林木垂直分层虽较简单,但结构稳定,具有发育成熟的顶极森林群落的空间分布特征;坑底植物群落的种群主要呈聚集分布,种群间呈负关联,且处于同一垂直层次上种群间空间负相关性更强,垂直层次相差越大,空间竞争性越小,而随着空间范围的增大,空间负关联越弱;坑内生态系统具有较高的稳定性,是难得的物种自然栖息地和生态避难所,独特生境中形成的稳定植物群落结构在喀斯特地区生态恢复研究中具有重要的借鉴意义和导向作用.

Spatial pattern of plant community in original karst tiankeng: A case study of Zhanyi tiankeng in Yunnan,China

Damaosi is one of original karst tiankengs with underground virgin forest in Yunnan Pro-vince. The spatial point pattern analysis and the woody individual spatial structure parameters, including the uniform angle index, mingling degree and storey index, were used to estimate spatial pattern of the tiankeng’s underground forest community. We also analyzed the intraspecific spatial distribution characteristics and interspecific spatial association on the basis of the individual relative position information of plant community. The results showed that the spatial distribution of plant community in Damaosi tiankeng was random. Plant species in the forest were moderately mixed. The vertical stratification of this forest was relatively simple, with stable structure and mature development characteristics of climax forest community. The populations in this community were mainly clustered in spatial distribution, negatively correlated between species and stronger negative correlation on the same vertical level. The larger the difference in the vertical level, the smaller the space competition was. The negative correlation in space became weaker with the increases of spatial scale. Tiankeng ecosystem was one type of precious natural habitats and plant refuges with high ecological stability. The stable structure of tiankeng plant community had important implications for the ecological resto-ration in karst areas.