马尾松—木荷不同比例混交林林下植被物种组成及其多样性分析

以飞播马尾松林为研究对象，按其树种组成分为10马(10马尾松，类型Ⅰ)、8马2木(8马尾松-2木荷，类型Ⅱ)、7马3木(类型Ⅲ)、6马4木(类型Ⅳ)4种类型设置典型样地，分析比较其林下植被物种组成及多样性。结果表明:1)从类型Ⅰ至类型Ⅳ林下植被的物种数增加，类型Ⅰ为11种，类型Ⅳ为28种；随着木荷比例的增加，林下植被阳生植物的优势地位表现为先增强再逐渐减弱或消失，而喜湿植物的地位逐步提升甚至成为优势种。2)林下灌木及草本Shannon-Wiener多样性指数、Patrick丰富度指数、Pielou均匀度指数均在类型Ⅳ时达到最大，表现为类型Ⅳ>类型Ⅲ>类型Ⅱ>类型Ⅰ。3)木荷比例与林下灌木及草本Shannon-Wiener多样性指数和Patrick丰富度指数呈显著(P<0.05)或极显著正相关(P<0.01)，与Pielou均匀度指数相关不显著(P>0.05)；拟合得出林下灌木及草本Shannon-Wiener多样性指数和Patrick丰富度指数达峰值的木荷比例分别为0.43、0.54、0.57、0.50，对拟合曲线分析表明飞播马尾松林补植木荷比例在43%~57%之间其林下植被多样性达到最大值。

Undergrowth Species Composition and Diversity of Pinus massoniana and Schima superba Mixed Stands with Different Proportions

Schima superba seedlings were planted in aerially-seeded Pinus massoiana plantations with 4 proportions: type I: pure P.nassoiana (10),type Ⅱ(8 P.massoniana + 2 Schima superba)，type Ⅲ(7+3),and type Ⅳ(6+4) to compare and analyse undergrowth species composition and diversity．Following results were obtained:1) from type I to type Ⅳ,the number of plant species increased,11 species were found in type I,and 28 in type Ⅳ；with the increase of the proportion of S.superba,the dominance status of heliophytes increased and then decreased gradually or disappear，while the dominance status of the hygrophytes increased gradually and even become the dominant species．2) Shannon-Wiener diversity index，Patrick richness index and Pielou evenness index of the understory shrub and herb were in the order of type Ⅳ> Ⅲ> Ⅱ> I．3) The correlationships of the proportion of S.superba with Shannon-Wiener diversiy index and Patrick richness index of derstory shrub and herb were significantly positive (P<0.05) or extremely significantly positive (P<0.01),and not significant (P>0.05) with Pielou evenness index; simulations indicated that Shannon-Wiener diversity index and Patrick richness index reached the maximum value when the proportion of S.superba were 0.43，0.54，0.57，and 0.43,respectively.The fitted curve showed that the diversity of undergrowth reached maximum when aerially seeded P.massoiana plantations replanting with 43%-57% S.superba.