海南岛霸王岭热带山地雨林林隙更新生态位的研究

Study on the Regeneration Niche of Major Tree Species in Gaps in a Tropical Montane Rain Forest in Bawangling, Hainan Island

通过对海南岛霸王岭热带山地雨林林隙更新生态位的研究表明 :同一树种在不同大小和年龄级林隙内的优势度不同 ,不同树种在同一大小和年龄级林隙内的优势度不同。根据树种在不同大小级林隙内的生态位宽度的变化 ,可分为生态位幅度宽、中等、较小和狭小 4类 ;根据树种在不同年龄级林隙内的生态位宽度的变化 ,可分为对林隙时间生态资源利用充分、利用较充分、利用不充分和利用很少的 4类树种。不同的树种或树种组对不同大小和年龄阶段林隙生态资源利用的不一致性 ,表明热带山地雨林中不同树种的林隙大小级生态位和林隙时间段生态位是相对分离的。分析表明 ,海南岛热带山地雨林中有很大一部分树种是属于低密度、狭生态位的树种。从物种多样性的角度来看 ,大量低密度、狭生态位树种的存在表明热带山地雨林是一种较为脆弱的生态系统类型。

On the basis of investigation on gaps in the tropical montane rain forest of Bawangling Nature Reserve, Hainan Island, regneration niche and related characteristics were analyzed. The results showed that dominances of the same species in gaps of different sizes and developmental stages were different. And dominances of different species in gaps of the same sizes and same developmental stages were also different. According to values of niche breadth based on gap sizes, the species were classified into 4 types, i. e. the wide, middle, comparatively narrow and narrow amplitute of niche. According to values of niche breadth based on gap age classes, the species in the tropical montane rain forest were classified into 4 types, i. e. efficient utilization on gap resources comparatively efficient utilization on gap resources not efficient utilization on gap resources, and very few utilization on gap resources. The non-uniformity of species utilization on resources in gaps of different sizes and age classes indicate that niches based on gap sizes and gap age classes for different species were comparatively separated. Through the formation and development of different sized gaps, tree species satisfied their life history process requirements, so that many species can coexist consistantly in the tropical montane rain forest. Calculations on the dominances and niche breadth of tree species in gaps of different sizes and age classes showed that there are a great proportion of low density, narrow niche species in the tropical montane rain forest. These species have a high dependence on whole ecological environment in the tropical forest ecosystem. The probabilities of local extinction are high once the environment changed. The existence of vast quantity of low density, narrow niche species in the forest indicates that the tropical montane rain forest ecosystem is a vulneralbe ecosystem type in terms of species diversity. Great attention should be paid to the diversity conservation of the low density, narrow niche species when any management measures are taken to the tropical montane rain forest.