广西大青山西南桦人工林林下植物多样性与稳定性

Species diversity and community stability of Betula alnoides plantations in Daqingshan mountain areas of Guangxi

以广西大青山西南桦人工林为研究对象,根据林分类型设置53块20 m×30 m典型样地,在群落学的调查基础上,分析西南桦人工林植物多样性和群落稳定性,揭示了人工植被的动态变化特征。结果表明:(1)大青山林区西南桦人工林,记录到林下植物种类76科139属164种;植物优势种重要值所占比例较大(西南桦纯林49.77%,西南桦×红锥混交林58.40%,西南桦×灰木莲混交林50.04%,西南桦×杉木混交林58.17%和西南桦×马尾松混交林70.18%),其在群落结构和演替发展中占据优势地位。(2)灌木层植物种类最多,ShannonWiener指数和Simpson指数均表现为灌木层>乔木树种>藤本植物>草本层。(3)利用改进的M.Godron稳定性测定方法测得,人工林下植物群落均处一定的稳定状态,说明植物群落的物种多样性越大,群落结构越复杂,有利于维持群落的稳定。

The 53 plots of 20 m×30 m were set up according to stand types of Betula alnoides plantations in Daqingshan forest region,there were selected to study the species diversity and community stability of the plantations,In order to explore the dynamic characteristics and change mechanism of artificial vegetation.The results showed that：（1）A total of 164 species belonging to 139 genera and 78 families were recorded across forest types,there were a large proportion in the importance values of dominant species（the pure plantations49.77%,Betula alnoides×Castanopsis hystrix mixed plantations 58.40%,Betula alnoides×Manglietia glauca mixed plantations 50.04%,Betula alnoides×Cunninghamia lanceolata mixed plantations 50.04%,Betula alnoides×Pinus massoniana mixed plantations 70.18%）,its occupied the favorable position in structure of community and succession.（2）Shrub plants was the most abundant species in Betula alnoides plantations,Shannon-Wiener index and Simpson index showed shrub layer 〉arbor species 〉vine species 〉herb layer.（3）Using the modified method of M.Gordon to measure the stability of 4 communities,the plant communities was stable state in the artificial forest,with more species diversity of plant communities,forest structure is more complex and stability is better.