森林采伐对尖峰岭海南特有种子植物多样性的影响

特有种子植物是热带森林植物区系的一个重要组成部分,且很容易受到人为干扰的影响,但是森林采伐对特有种子植物的影响少有报道。本文基于164个25m×25m植被公里网格样地数据,分析了海南岛尖峰岭地区海南特有种子植物(以下简称特有种子植物)的组成结构、样地内特有种子植物物种数与总物种数之间的关系;并从种-面积曲线、累积种-个体关系和物种多度分布3个方面比较了原始林、径级择伐林和皆伐林样地中特有种子植物的物种多样性变化规律。结果显示:尖峰岭地区特有种子植物种类丰富,共有158种,占全岛(397种)的40%;其中木本特有种子植物达98种(藤本除外),在164个样地内共记录到胸径≥1.0cm的52种,占整个尖峰岭地区的53%,以樟科、壳斗科、茜草科种类为主。样地内特有种子植物的物种数与总物种数成正相关关系。采伐后特别是径级择伐后特有种子植物物种数略微增加,但增加的种类大多仅在1-2个样地中出现;而且种群也比较小,表现为较稀有且不稳定的种群结构特征,在后续的更新中消失的可能性较大。但是,采伐后一些特有种子植物仍具有中等大小的种群,例如毛荔枝(Nephelium topengii)、海南紫荆木(Madhucaha inanensis)和尖峰岭锥(Castanopsis jianfenglingen-sis)等。

Impacts of forest logging on the species diversity of endemic seed plants from Hainan Island

Endemic seed plants are important floral components in tropical rainforests,and are often sensitive to human disturbance.However,few reports exist of the impacts of forest logging on these species.In this study,based on surveys of 164 quadrats of 25 m×25 m in Jianfengling,Hainan Island,the species composition and relationships between species richness of Hainan endemic seed plants and the total plant species richness were analyzed.Each of the 164 quadrats was grouped into one of three forest types,including old-growth,selectively logged and clear-cut forests.Then changes in species diversity were studied by comparing species-area relationships,cumulative species-individual relationships and species abundance distributions for the Hainan endemic seed plant species among the three forests types.Results highlighted the abundance and diversity of endemic seed plant species in Jianfengling.We found 158 species which acount for 40% of all endemic seed plant species found on Hainan Island,including 98 woody species(excluding lianas).Fifty-two woody endemic seed plant species(excluding lianas) from Hainan Island were recorded in the 164 quadrats;53% of all woody endemic seed plant species in Jianfengling.Among them,Lauraceae,Fagaceae and Rubiaceae are dominant families.The richness of the woody seed plant species endemic toHainan Island was linearly correlated with the total plant species richness in the quadrat.After forest logging,the number of woody endemic seed plant species appears to increase slightly,especially in selectively logged forests.However,the woody endemic seed plant species that appear to increase post-logging only occur in 1-2 quadrats and have relatively small and unstable populations,and may therefore disappear during forest succession.On the other hand,some endemic seed plant species still have medium populations after logging,such as Nephelium topengii,Madhuca hainanensis and Castanopsis jianfenglingensis.