南方红豆杉迁地保护种群的点格局分析

Point pattern analysis of ex-situ population of Taxus wallichiana var.mairei

南方红豆杉为国家I级珍稀濒危保护植物。为阐明其迁地保护种群的空间分布格局，采用点格局分析法对南京紫金山西麓各龄级南方红豆杉的空间格局进行测定，并分析其不同龄级的相互关系。结果表明：Ⅰ龄级个体在小尺度（1～4 m）和大尺度（10～15 m）下呈随机分布，中尺度（4～10 m）下为集群分布，Ⅱ龄级个体在所有尺度下均为集群分布，而Ⅲ龄级个体在所有尺度下均呈随机分布，总体上看，该迁地种群呈现集群分布；龄级Ⅰ与Ⅱ的个体之间，在1～ 4 m和10～15 m下呈正关联，而在4～10 m下无显著关联，龄级Ⅰ与Ⅲ的个体在1～6 m和13～15 m下无显著关联，而在6～13 m下呈负关联；Ⅱ与Ⅲ龄级个体在所有尺度下均无关联；目前南方红豆杉迁地种群以低龄级个体为主，主要呈现集群分布，并且不同龄级从小到大表现出与野生种群相似的空间格局，因此建议对母株附近的紫金山次生林应尽量减少人为干扰并保护其生境，这将有利于该种群规模的增加及分布面积的扩展。

Taxus wallichiana var. mairei, a rare and endangered species, ranks as the first class on the List of the Important Wild Plants for Conservation in China （first passel）. By applying Ripley’s point pattern analysis, we examined the spatial distribution patterns and the associations among different age-classes of T. wallichiana var. mairei ex-situ population from the western foothills of Zijin Mountain to elucidate its spatial distribution characteristics. The results showed that individuals of ageclass I presented a random distribution at small spatial scales （1-4 m） and large scales （10-15 m）, but with an obvious clumped distribution at medium scales （4-10 m）. At all scales, individuals of age-class Ⅱ performed an evident clumped distribution. However, individuals of age-class Ⅲ had a random distribution. Overall, the ex-situ population presented a clumped distribution. The spatial association of individuals between age-classes I and Ⅱ had a significantly positive correlation both at small spatial scales （1-4 m） and large scales （10-15 m）, whereas there was no significant correlation at the rest of scales. Individuals of age-class I had a negative correlation with those of ageclass Ⅲ at the spatial scales of 6-13 m, but they did not have an obvious correlation at the rest of scales. In contrast, age-class Ⅱ had no obvious correlation with age-class Ⅲ at all scales. Considering that most young individuals mainly presented clumped distribution and that the intraspecific association of this ex-situ population was similar to that of wild population, all efforts that can minimize human disturbance and protect suitable habitats of the secondary forest near the mother trees in Zijin Mountain should be made to increase the population size and distribution area.