Using pitfall trapping,the effects of four hedgerow plant species,which serve as undisturbed and permanent seminatural habitats,on activity density (a parameter of population density and relative activity) and family richness of grounddwelling beetle were investigated.Samples were collected over two winter wheat and two summer maize growing seasons during 2005-2007 in trial field 1 (slope gradient of 20°) and field 2 (slope gradient of 12°) at the Ziyang Experimental Site in Sichuan province,China.The hedgerow species evaluated were Amorpha fruticosa (field 1),Vetiveria zizanioides (field 1),Eulaliopsis binata (field 2),and Medicago sativa (field 2).The results indicated that the activity density of ground-dwelling beetles did not show significant difference between the hedgerow strips and the bare soil or the adjacent crop fields during the wheat season,and was significantly lower in the hedgerow strips than in the bare soil or the adjacent crop fields during the maize season.The family richness of ground-dwelling beetles did not show significant difference between the hedgerow strips and the bare soil during the wheat or maize seasons.The presence of hedgerow strips did not augment the activity density and family richness of ground-dwelling beetles within the crop fields during the wheat or maize seasons.Based on these results,it was concluded that due to the narrow width and the simplicity of vegetation structure,the hedgerow strips,which contributed to controlling soil conservation,had no effect on increasing the diversity of beetles in agro-ecosystems.%2005-2007年的冬小麦和夏玉米生长季节,在四川省土壤肥料研究所资阳试验站的1号试验地(坡度20°)和2号试验地(坡度12°)利用陷阱法调查了香根草(1号地)、紫穗槐(1号地)、蓑草(2号地)和苜蓿(2号地)4种植物篱物种作为半自然生境对地表甲虫的活动密度(种群密度和活动性的参数)和科丰富度的影响.结果表明,植物篱带地表甲虫的活动密度在小麦生长季节与对照裸地或临近农田之间差异不明显,在玉米生长季节明显低于对照裸地或临近农田.植物篱带地表甲虫的科丰富度在小麦生长季节和玉米生长季节与对照裸地之间差异均不明显.在小麦和玉米生长季节,植物篱带的出现均没有明显提高农田地表甲虫的活动密度和科丰富度.以上结果表明,有助于保持水土的植物篱由于宽度较窄、植被结构简单,导致对提高农田生态系统地表甲虫的物种多样性作用不明显.
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