珍稀濒危树种陆均松天然种群结构与空间分布格局

为研究陆均松(Dacrydium pectinatum)种群生存现状及分布格局,对BWL、DLS、JFL三种不同分布区域的陆均松天然种群进行了调查,分析了其天然群落乔木层物种多样性及优势种组成、龄级结构及分布格局三个方面的空间异质性,结果表明:(1)三种陆均松天然群落乔木层物种丰富度及多样性指数均较高,基本表现为BWLJFLDLS,且远高于中高纬度温带及亚热带森林群落;群落内多为小密度种群,少有占绝对优势地位的树种,符合热带山地雨林物种组成的一般规律。(2)龄级结构有所差异,BWL和JFL种群呈衰退趋势,共同特点是幼年树数量较少,成年和老年树比例较高;DLS种群幼年树数量在所有个体中比例最高,属于增长型种群。(3)BWL和DLS种群整体呈聚集分布,幼年至老年阶段由聚集分布转变为均匀分布,JFL种群整体及不同发育阶段均呈均匀分布状态;聚集强度表现为DLSBWLJFL,幼年树成年树老年树。陆均松是热带山地雨林的关键种和建群种,对研究海南热带雨林的起源及其区系特征具有重要意义,针对其生存现状,可根据实际情况,利用人工辅助措施如开辟林窗、合理疏伐等方式进行保护及更新复壮。

Natural population structure and spatial distribution pattern of rare and endangered species Dacrydium pectinatum

In order to study the survival status and distribution pattern of Dacrydium pectinatum population, we investigated three different distribution areas, namely BWL, DLS, and JFL in Hainan Island. The spatial heterogeneity in three aspects of the species diversity and dominant species composition of the natural community arbor layer, age structure, and distribution pattern was analyzed. The results showed that (1) the arbor layer species abundance and diversity index of the three D. pectinatum natural community were higher as a whole, which followed the order of BWL > JFL > DLS, and much higher than those of the mid-high latitude temperate zone and subtropical forest community. The populations in the community were mostly small-density populations, and there were few absolutely dominant species, which is consistent with the general rule of species composition of tropical mountain rainforests. (2) The age structure of these three populations had its own characteristics. BWL and JFL showed a recession trend. The common feature was that the number of Juvenile tree was small, and the proportion of adult trees and elderly trees was high. The number of Juvenile tree in DLS was the most for all individuals and belonged to the growth population. (3) The overall state of the D. pectinatum population of BWL and JFL was aggregate clustered distribution. The juvenile tree stage was also a clustered distribution, but in the elderly tree stage, it changed from clustered distribution to uniform distribution. The JFL D. pectinatum population showed a uniform distribution throughout all individuals and different developmental stages. Their aggregation intensity was expressed as DLS > BWL > JFL and juvenile > adult > elderly. D. pectinatum is a key species of tropical mountain rainforests, which is of great significance for studying the origin and flora characteristics of Hainan tropical rainforest. For its current survival status, we can use manual auxiliary measures such as opening forest windows and rational thinning to protect and rejuvenate D. pectinatum population based on the actual situation.