中文摘要：

Yongxing 岛是在华南海的中间的部分的 Xisha 岛的最大的岛。它占据陆地区域的 1,8 方形的公里并且在它上有永久住处。仅仅 Xisha 岛的珊瑚社区上有一些论文，报导在 1970 年代的 hermatypic 珊瑚社区的种类作文，结构和带状配列。现在的学习在 2002 年 8 月在几乎 30 年 inYongxing 岛以后基于空铅调查描述 hermatypic 珊瑚社区。经由量的空铅采样的一个系统的计划介绍 Yongxing 岛的实时珊瑚的百分比盖子数据是第一次。实时珊瑚的平均全部的百分比盖子是 68.4% 。我们发现全部的百分比盖子(TPC ) 能是在珊瑚社区上侵犯的全面骚乱政体的一个想法代理。TPC 能被用作骚乱的一项综合措施到珊瑚礁石。用这个代理人，在实时珊瑚和种类丰富的 TPC 之间的最好的合适的关系，种类差异，或种类，平均是单峰的秒顺序多态的抛物线方程。这结果被中间的骚乱假设(IDH ) 期望。从适合的抛物线方程，我们分别地计算了最好的 TPCscorresponding 到最大的种类丰富，最高的种类差异，或大多数平均。他们令人惊讶地在 55% 和 58% 之间被稳定。

英文摘要：

The Yongxing Island is the biggest island of Xisha Islands in the middle part of the South China Sea. It occupies 1.8 square kilometers of land area and has permanent residence on it. There are only a few papers on the coral community of the Xisha Islands, reporting the species composition, structure and zonations of the hermatypic coral community in 1970s. The present study describes the hermatypic coral community based on the quadrat survey after almost 30 years in Yongxing Island in August 2002. It was the first time to present the percent cover data of live corals of Yongxing Island via a systematic scheme of quantitative quadrat sampling. The average total percent cover of the live coral is 68.4%. We found the total percent cover （TPC） could be an idea proxy of the overall disturbance regime impinging on the coral community. TPC can be used as an integrated measure of disturbance to coral reef. Using this surrogate, the best fit relation between TPC of the live corals and species richness, species diversity, or the species evenness is the unimodal second-order polymorphic parabola equation. This result is expected by the intermediate disturbance hypothesis （IDH）. From the fitted parabola equations, we calculated the best TPCs corresponding to the maximal species richness, the highest species diversity, or the most evenness respectively. They are surprisingly stabilized between 55% and 58%. Coral cover is the basic parameter widely available for most observation, research or monitoring programs. The good qualitative characteristics of percent cover provide powerful tool for the experimental, theoretical and modeling studies of coral reef in response to the disturbance.