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通过调查石灰岩及花岗岩两种不同生境样地内海南龙血树分布和胸径/基径情况,分析其龄级结构,用相邻格子法对海南龙血树进行每木调查,并采用方差/均值比率法和丛生指数(I)、负二项参数(K)、平均拥挤度(m*)、聚块性指数(PAI)、聚集指数(Ca)等聚集强度指数对海南龙血树种群分布格局进行分析。结果表明:石灰岩及花岗岩样地内的海南龙血树种群皆呈衰退型,其中天安乡、江边乡两样地种群的幼苗储备不足,昌化镇及东澳镇两地的中龄级植株数量稀少,大小洞天样地的种群年龄结构不完整;石灰岩样地内的海南龙血树种群在不同尺度、不同阶段上主要表现为集群分布,花岗岩地区种群的不同组分在不同取样尺度上分布格局相同,幼龄树、中龄树、老龄树的分布格局分别为集群分布、均匀分布、集群分布。
Based on the investigation of the distribution of Dracaena hupensis and the diameter at breast height and the diameter at base of two different habitats of limestone and granite, the age-class structure was analyzed. The adjacent grid method was used to survey each species of Dracaena leucocephala, and the variance / mean ratio (I), negative binomial parameters (K), mean crowding degree (m *), polyphagous index (PAI) and aggregative index (Ca) analysis. The results showed that all the populations of Dracaena senegalensis in the limestone and granite plots showed a declining pattern, in which the seedlings of two populations in Tian’an and Jiangbian townships were scarcely stocked and the number of middle-aged plants in Changhua and Dong’ao was scarce , And the age-structure of cave-like populations is not complete. The population of Dracaena diversifolia in the limestone plots is mainly distributed in different scales and stages, and the distribution pattern of the different components in the granite area is the same on different sampling scales. The distribution patterns of young, middle-aged and aged trees are cluster distribution, even distribution and cluster distribution.