汶川地震滑坡迹地植物群落与环境的关系

为了加快汶川地震滑坡迹地人工恢复植被的进程,探讨地震诱发的滑坡迹地植物群落与环境的关系。在5·12地震重灾区北川境内选取29个样地进行植被调查,采用10个环境指标刻画植物群落的地形、空间位置和土壤养分特征;利用TWINSPAN、CCA、DCA和DCCA,分析植物种、植物群落和植物生活型与环境的关系。结果显示:1)研究区的植物群落可划分为9个类型。2)研究区环境变量对植物种的解释量为21.96%,第一排序轴与pH值、海拔、土壤质地相关,反映的是植物种从次生植物群落向原生植物群落变化。通过DCCA分析得出,环境变量对植物群落的排序解释了25.7%,第一排序轴与pH值、海拔、土壤质地的相关较强,反映植物群落按照耐旱、耐贫瘠→人工或先锋植物→未受损的植被变化;第二排序轴与土壤有机质、全氮含量、坡向的相关,反映的是植物群落从草本植物→乔灌草或者灌草植物变化。3)滑坡迹地的植物群落与未受损林地的植物群落物种存在较大差异。

Relationship between plant communities and environment after landslide of Wenchuan Earthquake

To shorten the process of vegetation restoration on the landslide sites of Wenchuan Earthquake, this study explored the relationship between plant communities and environmental factors. A total of 29 sample plots in Beichuan, the area of earthquake that occurred on May 12, 2008, were selected to conduct vegetation investigation, adopting 10 environmental indicators that describe the terrain, location, and soil nutrient characteristics of plant communities. Two-way indicator species analysis, canonical correspondence analysis, de-trended correspondence analysis, and de-trended canonical correspondence analysis were used to analyze plant species, plant communities, and plant life styles. The results showed the following: 1) Plant communities within the study area were classified into nine types. 2) The first two axes representing plant species explained 21.96% of the environmental factors; Axis 1 was related to pH, altitude, and soil texture, indicating the transformation from the secondary plant community to the primary plant community. By using de-trended canonical correspondence analysis, the environmental variables explained 25.7% of the ordination plant community, and Axis 1 showed a strong correlation with pH, altitude, and soil texture, demonstrating that plant community composition varied from drought and barren resistant plants to artificial or pioneer plants and to intact vegetation. Axis 2 correlated with soil organic matter, total nitrogen content, and slope direction, illustrating the change in plant communities from herbaceous plant community to tree-shrub-grass or shrub-grass type of vegetation. 3) Plant community composition on the landslide sites was significantly different from that of intact forest sites.