广东古兜山保护区光叶红豆种群径级结构与空间分布格局

Diameter Structure and Spatial Distribution Pattern of Ormosia glaberrima Population in Gudushan Reserve, Guangdong

关键词:  珍稀濒危植物  光叶红豆  径级结构  空间分布格局  就地保护  迁地保护

Key words:  Rare and endangered plant  Ormosia glaberrima  Size?structure  Spatial distribution pattern  In-situ protection  Ex-situ protection

摘要:

为了解广东古兜山省级自然保护区内天然分布的珍稀濒危植物光叶红豆Ormosia glaberrima种群的生存现状，本研究基于1hm2固定样地数据，进行种群径级结构分析，并采用点格局分析方法研究种群空间分布格局。结果表明，光叶红豆的径级结构呈倒“J”型，个体以幼树为主，同时幼树和壮龄树死亡率也较高，随着径级增大，个体的存活率趋于稳定，整体表现为增长型，种群结构较为稳定；在小空间尺度上，光叶红豆个体间呈聚集分布，而随着空间尺度的增大，个体倾向于呈随机分布。光叶红豆幼树呈聚集分布，随着径级增加，空间分布的聚集程度下降，成树呈随机分布。因此，古兜山光叶红豆种群的空间分布格局主要受幼树、壮龄树死亡率较高和密度制约影响，建议通过适度开辟林窗等方式加强就地保护，结合迁地保护降低幼树密度，促进光叶红豆种群更新。

Abstract:

In order to understand the survival status of the rare and endangered plant Ormosia glaberrima population in Gudoushan Provincial Nature Reserve in Guangdong Province, this study analyzed the population size structure based on the data of 1 hm2 forest plot, and used the point pattern analysis method to study the spatial distribution pattern of the population. The results demonstrated that the size structure of O. glaberrima was an inverted "J" shape, and the individuals were mainly saplings. In addition, the mortality rates of saplings and middle-age trees were higher as compared to adults, and the survival rate of individuals tended to be stable with the increase of diameter class, the overall age structure was growth-type and the population structure was stable. On the small spatial scale, the O. glaberrima individuals were spatilly clustered, and with the increase of spatial scale, individuals tended to be randomly distributed. The saplings of O. glaberrima were clustered, and with the increase of diameter class, the degree of aggregation decreased, and the adult trees were randomly distributed. Therefore, the spatial distribution pattern of the O. glaberrima population in Gudoushan was mainly affected by the high mortality rate and the negative density dependence of saplings and middle-age trees. It was suggested to strengthen in situ conservation by appropriately create forest gaps, and reduce the density of saplings in combination with ex situ conservation, so as to promote the population regeneration of O. glaberrima.