坡面植被恢复过程中植被与土壤特征评价

为了加快建设工程损毁立地植被群落正向演替,探究土壤特性与植被生长效果的响应关系,选取北京市延庆县上辛庄水土保持科技示范园20个典型绿化护坡小区为评价单元,运用主成分分析及聚类分析法在求得各护坡小区综合评价得分的基础上,将20个护坡小区划分为3类。采用Margalef指数、Pielou指数、Simpson指数和Shannon-Wiener指数评价了3类护坡小区植被群落年际分异特征,并构建了5种模式的植被-土壤环境耦合度及其预测模型。结果表明:1)坡面植被恢复过程中以土质边坡为主的护坡小区植被恢复效果普遍优于岩质边坡组成的护坡小区。2)随着年份的增加,3类护坡小区物种多样性指数增大,变异系数减小,植被演替愈加剧烈。3)植被恢复5a后,植被-土壤耦合协调程度不是十分理想,以土质边坡为主的护坡小区处于中级协调发展阶段,岩质边坡组成的护坡小区仅处于初级协调发展阶段。该研究可为建设工程损毁立地边坡植被恢复提供参考依据。

Evaluation of vegetation and soil characteristics during slope vegetation recovery procedure

Abstract: In recent years, the implementation of the development and construction projects has destroyed original ecological barrier, which results in a series of environmental problems, such as water losses and soil erosion, landslide, vegetation coverage degradation and diversity of species decrease, which will endanger human life and property safety. It is urgent and necessary to figure out the relationship between soil properties and vegetation growth, based on which measures can be designed and conducted to maintain stability and sustainable development of natural environment, as well as to recover or reconstruct the sites impaired by construction projects, and then keep life and property from threat damaged.In this study, 20 typical slope protection districts in Soil and Water Conservation Science and Technology Demonstration Park in Shangxinzhuang, Yanqing county of Beijing were chosen as evaluation units. Several parameters related to vegetation recovery were simplified into four independent principal components with specific functions using principal components analysis (PCA) method, including vegetation characteristics, soil physical properties, soil chemical properties and site conditions. Principal component scores were used for cluster analysis, and the 20 districts were divided into 3 groups. The comprehensive scores of every protection district were identified by using scores of 4 principal components and the corresponding eigenvalue weights, and then they were combined with the results of cluster analysis to assess the vegetation recovery effect of 3 types of slope protection districts. Margalef richness index, Pielou evenness index, Simpson index and Shannon-Wiener diversity index were used to evaluate inter-annual differentiation characteristics of vegetation community in different groups of districts and to construct 5 prediction models with different vegetation-soil degrees of coupling, within which the effects from both soils and plants were integrated.The results showed that: 1) Group I and Group II of districts, which mainly consisted of soil slopes, had significantly better vegetation restoration effect compared to Group III, which mainly consisted of rock slopes. 2) With the passage of time, the diversity index increased, the coefficient of variation decreased, and vegetation succession processed in a more dramatic manner in all groups of districts. 3) After 5 years of recovery, the vegetation-soil coupling coordination degrees of all districts achieved not so good coordinated development stage. Group I and Group II belonged to intermediate coordinated development stage, while Group III belonged to primary coordinated development stage. The vegetation-soil systems of all 3 groups of districts were in a transition period from primary coordinated development towards to intermediate coordinated development.The method of simplifying vegetation recovery factors by CPA combined clustering analysis to divide protection slope type is effective and it can not only ensure the data comprehensive, but also confirm the typicality when evaluating the vegetation recovery effect. In addition, the model constructed by soil properties and vegetation properties combined soil and vegetation system suitably which can evaluate the vegetation recovery effect in all protection districts. This research can guide the vegetation recovery of slopes damaged by construction projects for governors and executors. Measures of vegetation restoration in bare slopes and inner relationship of vegetation-soil need further investigation in the future.