The Maintenance of Rare Species in the Dipterocarp Rain Forests of Borneo: Phase II

生态学的一个中心问题是解释在热带雨林中发现的大量稀有树种是如何随着时间的推移而保持的。这些树种中约70%的密度低于每公顷2棵。自1965年以来，在婆罗洲西北部使用一组独特的三种不同的龙脑树森林，对物种稀有度和森林动态进行了长期研究。利用这些数据，结合1986年至1988年的树苗和幼苗调查以及详细的森林地图，正在检验解释稀有物种维持的假设。一个森林遭受周期性的灾难性干旱，在此期间树冠树木死亡，而另一个森林由于当地的山体滑坡而在空间上异质性。物种丰富度在森林中最高，在土壤肥力和干扰程度中处于中等水平。由于这些森林之间的差异，这些森林的物种丰富程度可能不是一个简单的解释。目前正在与马来西亚森林部负责森林管理实际问题的成员共同分析这些数据。研究结果也与关注生物多样性维护的保护生物学家有关。

A central problem in ecology is to explain how the great numbers of rare tree species found in tropical rainforests are maintained through time. Approximately 70% of these species occur at a density of less than 2 trees per hectare. Long-term studies of species rarity and forest dynamics using a unique set of three contrasting dipterocarp forests from northwest Borneo have been censused since 1965. Hypotheses which explain the maintenance of rare species are being tested using these data combined with sapling and seedling surveys from 1986 to 1988 and detailed forest maps. One forest is subject to periodic catastrophic drought during which canopy trees die while a second forest is heterogeneous in space due to local landslips. Species richness is greatest in forest which is intermediate in soil fertility and levels of disturbance. Because of these differences among forests, there may not be one simple explanation for the great species richness of these forests. These data are being analyzed jointly with members of the Malaysian Forest Department concerned with practical matters of forest management. The results are also relevant to conservation biologists concerned with the maintenance of biological diversity.