摘要:季风常绿阔叶林是我国南亚热带地区的地带性植被，有研究表明过去23年其群落结构和物种组成发生了很大变化，但对群落种间关系的动态变化还缺乏了解。该研究利用鼎湖山季风常绿阔叶林1 hm²监测样地7次群落调查数据，采用方差比率和Spearman秩相关分析的方法，对1992-2015年鼎湖山季风常绿阔叶林群落种间关系的长期动态变化进行了分析。结果表明：从1992年到2015年，群落方差比率都显著（P < 0.05）大于1，但方差比率总体呈显著下降趋势（R²=0.93，P < 0.001），显著正联结种对数显著减少，显著负联结种对数显著增多，群落正联结关系减弱；群落各垂直层次内和垂直层次之间显著正联结种对数呈显著下降趋势（P < 0.001），种间的正关联关系减弱；香楠（Aidia canthioides）、红枝蒲桃（Syzygium rehderianum）、光叶红豆（Ormosia glaberrima）等树种能够和大多数物种长时间稳定共存，在季风常绿阔叶林群落结构中可能具有重要地位和作用，可以作为华南地区生态恢复、林业种植的搭配树种。总的来说，1992-2015年，鼎湖山季风常绿阔叶林群落种间正联结关系减弱，负联结关系增强，导致群落种间关联愈加松散，群落稳定性下降。



Abstract:Monsoon evergreen broad-leaved forest (MEBF) is the climax vegetation type in the subtropics of China, and its structure and species composition have been shifting in the last 23 years. However, we know little about the dynamics of its interspecific associations. Our objective is to investigate the long-term dynamics of overall and pairwise interspecific associations in this forest community. In each community survey of the 1 hm² monitoring plot in the Dinghushan Biosphere Reserve, we recorded the species name, diameter at breast height (DBH), and tree height of every tree with DBH ≥ 1 cm. Up to now, seven surveys have occurred, in 1992, 1994, 1999, 2004, 2008, 2010, and 2015. In this study, we selected 29 dominant species according to their importance values, and studied the overall and pairwise interspecific associations by using variance ratio (VR) analysis and Spearman's rank correlation coefficient test, respectively, on the data from all surveys. From 1992 to 2015, the MEBF communities showed significant positive association; the VR values of all surveys were significantly > 1. However, in this period, the VR value of the community had decreased significantly (R²=0.93, P < 0.001), and the total significantly positively associated species pairs decreased significantly, while the total significantly negatively associated species pairs increased significantly. These results indicated that the positive associations in the MEBF community weakened over time, and the stability of the species composition of this forest had decreased, which possibly changed the ecological process and weakened the resistance of MEBF to biological invasion. The positive associations in and between vertical layers in the plant community were also weakened. In addition, we found that Aidia canthioides, Syzygium rehderianum, and Ormosia glaberrima had significantly positive associations with many species consistently from 1992 to 2015. This indicates that they could be of importance to community assembly and, potentially to restoration and afforestation in this area.





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