The hot-dry Yuanmou valley is a typical ecological system in the fragile Jinshajiang River area.To research the community structure and regeneration of Terminalia franchetii forest, a vitally important and typical natural forest ecosystem in Yunnan Province, China, Three T.franchetii communities were investigated using the quadrat survey procedure in 100 m2 with seven repeats for species diversity and seedling regeneration and analyzed using the Shannon-Wiener, Simpson, and Pielou indexes.Results showed that these communities, having 32 species belonging to 16 families and 28 genera, had a relatively low richness with dominant species of Heteropogon contortus and Arthraxon lancifolius.Recordings for the indexes were: Shannon-Wiener 1.35 - 2.82, Simpson 0.63 - 0.81, and Pielou 0.68 - 0.85.The Shannon-Wiener and Pielou in community Ⅰ was markedly low to community Ⅱ which was remarkably low to community Ⅲ, but the Simpson in community Ⅰ was slightly high to community Ⅱ which markedly high to community Ⅲ.Seedling regeneration in the T.fianchetii community occurred at the start and in the middle of the rainy season; then it gradually decreased towards the end of the rainy season and ceased with the beginning of the dry season.During drought,the number of one-year-old seedlings was sharply declined to 0.5 in 1.0 m2 which maybe survived in shielded during the dry season that was most serious in March and April.Less drastic changes for the year occurred with two-year-old and older seedlings, which implied that they were more stable and showed better adversity resistance in the differing community environments.Thus, reducing disturbances would improve the community environment making seedling establishment of T.franchetii possible, then allowing a viable spontaneous recovery of the native vegetation through natural regeneration.%元谋盆地是中国云南金沙江干热河谷生态脆弱区的典型区域.滇榄仁Termindia franchetii群落为该区域重要的代表性植被类型之一.采用样方调查的方法,对不同类型滇榄仁群落林下物种多样性及幼苗更新进行了比较研究.结果表明:①滇榄仁群落内物种组成较为简单,共有种子植物32种,隶属于16科28属;扭黄茅Heteropogoncontortus和矛叶荩草Arthraxon lancifolius等耐旱禾草为群落优势种.滇榄仁群落林下物种多样性程度较低,Shannon多样性指数为1.35-2.82,Simpson优势度指教为0.63-0.81,Pielou均匀度指数为0.68-0.85,不同群落类型间存在显著差异.②群落内滇榄仁更新主要发生在当年雨季早、中期,雨季结束进入旱季后,落地种子停止萌发,随着时间推移幼苗数量也随之减少,尤其是干旱最严重的3月和4月,幼苗数量降至最低,仅有少数处于荫蔽潮润环境下的植株能够存活.2年生及以上幼苗数量的年内变动较小,在不同群落环境中均具有较好的稳定性,说明它已具有较强的抗逆能力.③减少林下干扰使之形成良好的林下环境,滇榄仁幼苗能够成功定居,就可以通过天然更新达到乡土植被自然恢复的目的.
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