西双版纳热带森林树洞丰富度及其分配特点

树洞是森林生态系统的重要结构,对动物多样性的维持起着重要作用。为研究热带森林树洞的数量特征及其分配特点,选取西双版纳20hm2热带森林动态监测样地为研究对象,采用地面观测法调查了样地内所有胸径≥5cm活立木上的树洞。结果表明:(1)该样地森林的树洞密度为108.4个·hm-2,具有树洞的树1725株(占树木总数的6.22%),隶属于208个种;(2)树木个体的树洞数量随径级增加而增加,并在种间变化不均匀;(3)树木出现空心的概率随胸径级的增加而显著增加,并且在树种间存在显著差异;(4)与其他纬度地区森林的树洞密度比较,本研究结果支持了Boyle等(2008)提出的低纬度森林具有较高树洞密度的推测。

Abundance and distribution pattern of tree cavity in tropical forest in Xishuangbanna,Southwest China

Tree cavity is the key component of forest ecosystem, playing important roles in the conservation of animal diversity. To clarify the quantitative characteristics and distribution patterns of tree cavities in tropical forests, a ground-based observation was conducted in a 20 hm2 tropical forest dynamic monitoring plot in Xishuangbanna of Southwest China to survey the cavities on all the living trees with diameter at breast height (DBH) ≥5 cm. In the plot, 1725 trees belonging to 208 species, occupying 6.22% of the total, had tree cavities, and the mean density of the cavities was 108.4 cavities·hm-2. The number of the cavities per tree increased with DBH, and varied among tree species. The probability of the trees being cavity-bearing increased with increasing DBH, and differed significantly with tree species. As compared with the investigations on the tree cavities at other latitudes, our findings supported the inference proposed by Boyle et al. (2008), i.e., the forests at low latitudes would have a higher density of tree cavities.