退耕还林区水土保持植被恢复及物种多样性特征

采用对比流域试验方法，对陕西省吴起县封育自然恢复试验区合家沟流域和人工恢复柴沟流域进行野外调查分析。结果显示，实施退耕还林后，人工和自然的植被恢复方式在恢复10 a左右对于天然草本的生物多样性的影响不大。自然恢复试验区的植被的Margalef指数和Shannon—Wiener指数在峁顶和峁坡部位低于人工恢复区，而在沟坡和沟底部位高于人工恢复区；人工恢复区的Shannon指数和Pielou指数在峁坡和沟坡部位均高于自然恢复区，而在峁顶和沟底部位则较低。对土壤容重、土壤含水量、土壤总孔隙度、土壤毛管孔隙度和土壤非毛管孔隙度5个土壤物理性质指标与物种多样性指数进行相关分析表明，只有毛管孔隙度和非毛管孔隙度对物种多样性指数影响显著。

Characteristics of Vegetation Recovery and Species Diversity of Convertting Farmland to Forest in Northern Shaanxi

In order to understand the situation of vegetation recovery and plant community species diversities after conversion of cropland to forest,investigation was carried out in the fencing natural recovery test area in Hejiagou watershed and artificial restoration test area in Chaigou watershed in Wuqi Country,Northern Shaanxi,China.The results showed that there were no differences in herbaceous biodiversity between natural recovery and artificial restoration.The Margalef index and Shannon-Wiener index of natural recovery test area were lower than those of artificial restoration test area on the hilltop and mound slope.The Shannon index and Pielou index of artificial restoration test area were higher than those of natural recovery test area on the mound slope and valley slope,and opposite on the hilltop and gully bottom.By carrying on correlation analysis of the five soil physical indices,including soil density,soil water content,soil porosity,soil capillary porosity,non-soil capillary porosity,and species diversity,it was concluded that only capillary porosity and non-capillary porosity had significant effects on species diversity.