海南石梅湾青皮林最小取样面积与物种多样性研究

石梅湾海岸青皮(Vatica hainanensis)林是海南独特的雨林群落之一。本文选用8种“种-面积渐近线”对该群落的最小取样面积进行了拟合研究。结果表明，其中5条曲线的R^2大于0．97，拟合状况很好，但所得出的最小取样面积各不相同。进一步经过“重要值-面积曲线”的群落特征分析，确认群落的最小取样面积只有800m^2。石梅湾青皮林最小取样面积比海南其他类型雨林、滇南热带雨林、东南亚热带雨林以及非洲雨林都要小。通过对1000m^2样地的物种多样性分析，结果表明：在垂直结构上，石梅湾青皮林B层乔木的Gleason指数大于A层乔木，和海南山地雨林的情况不同。海岸青皮林为物种多样性不高的单优林，群落的物种多样性、均匀度远小于海南其他类型的山地雨林与混合青皮林；在海岸青皮林群落内，青皮的相对密度、相对优势度、重要值大大高于其他物种。此研究表明：海南热带雨林同样存在物种多样性不高、单优特征显著的顶极群落；海南海岸青皮林是迄今为止热带雨林取样面积最小的森林类型。

Minimum sampling area and species diversity of coastal Vatica hainanensis forest in Shimei Bay, Hainan Island

Coastal Vatica hainanensis forest in Hainan is a special type of tropical rainforest. To analyze this community, we used methods of sampling area analysis, including both quantitative mathematical modeling and qualitative comparison. 8 different mathematical models (species-area curves) were used to calculate the minimum sampling area and relevant coefficients. Importance values were derived to confirm the modeling consequences. Species diversity was also analyzed by various kinds of diversity indices. Results showed that the minimum sampling area of coastal Vatica hainanensis forest in Shimei Bay was 800 m2. This value of minimum sampling area was the lowest in global tropical rainforest types. Coastal Vatica hainanensis forest in Shimei Bay was a strongly mono-dominant forest with low species diversity. Thirdly , the pattern of tree layers in Shimei Bay, measured by the Gleason index, differed greatly from that of mountain rainforest on Hainan Island. The study revealed that Shimei Bay, Hainan Island hosts a natural rainforest climax community which has low species diversity and salient mono-dominant community characteristics.