广西大青山南亚热带森林植物群落的种间联结性

广西大青山地处广西西南部，对该地区的研究主要集中在人工林，而对其天然次生林植物群落种间联结性的研究尚未见有报道。该研究基于广西友谊关森林生态系统定位观测研究站1 km2固定样地的调查数据，用方差比率法( VR)和基于2×2联列表，通过χ2统计量检验、共同出现百分率( PC)、联结系数( AC)，对广西大青山主要乔木层17个树种、灌木层8个树种、草本层12个树种的种间联结性进行了研究。方差分析结果表明，乔木层的总体种间联结性表现为显著正关联，灌木层的总体种间联结性表现为不显著负关联，草本层的总体种间联结性表现为不显著正关联。不同检验结果表明，该区域植物群落主要乔木树种间具有正联结性的种对较多，大多数乔木树种的种间联结性较紧密；主要灌木树种的种间联结性较松散，草本层主要种间表现为弱联结性。物种生态习性、群落演替阶段等因素可能是造成这一特性的主要原因。未来应加强对其自然环境的管理和保护，如果有必要，可适度人工干预，促进天然次生林的演替。该研究结果为进一步研究南亚热带天然次生林植物群落演替规律、维持和保护其物种多样性奠定基础，也可为该地区人工林的树种选择与配置提供数据支撑，进而对其人工林的近自然经营提供一定的理论参考。

Interspecific associations between south subtropical forest plant community species in Daqingshan of Guangxi

The natural secondary forest in Southwest Guangxi is rich in typical forest communities; however, little is known about the inter specific associations of the dominate species. Hence, our objective was to investigate how the dominant species in the communities interact with each other. We sampled 1 km2 in the natural secondary forest, se-lected 17 tree species, 8 shrub species and 12 herb species according to importance values and studied inter specific associations by using variance ratio ( VR) analysis and χ2-tests, percentage co-occurrence( PC) and association coef-ficient ( AC) . There was a significant positive correlation of overall association among trees, an insignificant negative correlation among shrubs, and an insignificant positive correlation among herbs. χ2-tests showed that there was a pos-
itive association for 81 pairs and a negative association for 19 pairs and 5 pairs did not have a relationship among trees. There was a positive association for 14 pairs and a negative association for 12 pairs and 2 pairs did not have a relation-ship among shrubs. A positive association was found for 32 pairs and a negative association for 24 pairs and 5 pairs did not show a relationship among herbs. The main tree species were connected more closely whereas main shrub species association was loose and main herb species association is weak. The main causes for different associations were as-sumed to be ecological habits, community succession stage among others. In the future,the management and protection of the natural environment should be more strengthen,if necessary,manual intervention may be appropriate in order to promote the natural secondary forest succession. The research will provide the information only for understanding the current situation and trends in its plant community succession,but also for the future research on its plant community succession regular and the protection of its species diversity.