濒危植物狭果秤锤树群落内主要树种的空间分布格局和关联性

为了解狭果秤锤树(Sinojackia rehderiana)群落的物种共存机制,研究了群落0.5hm~2样地内5主要树种的空间分布格局和种间关联性。结果表明,香樟(Cinnamomum camphora)、紫弹树(Celtis biondii)处于群落上层,尾叶冬青(Ilex wilsonii)在群落中层,下层以狭果秤锤树、瓜木(Alangium platanifolium)为主。狭果秤锤树、香樟、尾叶冬青、瓜木在小尺度上均为聚集分布,随着尺度的增大呈现出均匀分布或随机分布的趋势;紫弹树在全部尺度上为随机分布。尾叶冬青、瓜木在较小尺度上与狭果秤锤树的空间分布呈负相关,而香樟、紫弹树与狭果秤锤树则在较大尺度上呈负相关性,香樟、紫弹树、尾叶冬青、瓜木两两之间均无明显空间相关性。因此,推断密度制约和种子扩散限制对狭果秤锤树群落空间格局形成起作用,生境异质性的影响没有明显表现出来,群落尚未达到稳定状态。

Spatial Pattern and Association of Main Species in Endangered Plant Sinojackia rehderiana Community

In order to understand the species coexistence mechanism of Sinojackia rehderiana community in Yongxiu County of Jiangxi Province, the spatial distribution pattern and associations of 5 main species in 0.5 hm² plot of S. rehderiana community were studied. The results showed that the vertical structure of the community was evident, Cinnamomum camphora and Celtis biondii were in upper layer; Ilex wilsonii in middle layer, and the dominant species were S. rehderiana and Alangium platanifolium in lower layer. Celtis biondii was distributed randomly at all spatial scales, and other 4 species were clumped distribution at small scale, and showed an uniform distribution or random distribution with the increment of scale. Ilex wilsonii and A. platanifolium were negatively associated with S. rehderiana at small spatial scale. However, Cinnamomum camphora and C. biondii had negative association with S. rehderiana at large spatial scale. There was no obvious association among C. camphora, C. biondii, I. wilsonii and A. platanifolium. Therefore, it was deduced that density restriction and seed diffusion restriction play a role in the spatial pattern formation of Sinojackia rehderiana community, and the influence of habitat heterogeneity is not obvious, and the community has not reached a stable state.