苜蓿田及不同邻作地地表步甲群落多样性及其扩散动态

本研究选取宁夏银川市贺兰山农牧场苜蓿地及苜蓿-玉米、苜蓿-小麦、苜蓿-防护林、苜蓿-休闲地4种邻作边缘带,用陷阱法对步甲科昆虫种类和个体数进行了调查,研究了地表步甲昆虫的物种组成与数量、多样性以及季节迁移动态。调查共采集步甲昆虫9239头,21种。其中毛青步甲(Chlaenius pallipes)、谷婪步甲(Harpaluscal ceatus)、彩角青步甲(Chlaenius touzalini)分别占总个体数的41.17%,18.77%,17.07%,为该地区的优势种类。分析表明,4种邻作型的苜蓿边缘地步甲丰富度为防护林-苜蓿边缘地>小麦-苜蓿边缘地=玉米-苜蓿边缘地>休闲地-苜蓿边缘地;多样性为小麦-苜蓿边缘地>防护林-苜蓿边缘地>玉米-苜蓿边缘地>休闲地-苜蓿边缘地;小麦-苜蓿边缘地的均匀度指数和优势度指数均为最高。苜蓿边缘地与相邻作物边缘地步甲群落多样性比较,前者的步甲多样性指数明显高于后者。地表步甲种群在苜蓿田边缘带与相邻作物田边缘带之间存在着明显的季节迁移,其迁移动态的程度受不同邻作作物类型、苜蓿刈割及灌水等农事操作的显著影响。

Diversity and diffusion dynamics of the ground-dwelling carabid beetle community in alfalfa fields and boundary edges of their adjacent crops

We conducted a pitfall trap survey in alfalfa fields and the boundary edges of their adjacent crops in Northwest China from May to July 2014-2015,to investigate the species and individuals in the ground-dwelling carabid beetle community.We selected four different habitat interfaces:alfalfa-wheat,alfalfa-corn,alfalfatree land,and alfalfa-fallow grassland.The component species,community diversity,and diffusion dynamics of carabid beetles in these habitats were analyzed.During the field research,we collected a total of 9239 carabid beetles belonging to 21 species.Chlaenius pallipes,Harpaluscal ceatus,and Chlaenius touzalini were the dominant species,accounting for 41.17％,18.77％,and 17.07％ of the total number of individuals,respectively.The four habitat interfaces were ranked based on carabid abundance index as follows:alfalfa-tree interface＞ alfalfa-wheat interface=alfalfa-corn interface＞alfalfa-fallow interface.Similarly,the four types of alfalfa fields were ranked based on their Shannon-Wiener diversity index as follows:alfalfa field adjacent to wheat＞alfalfa field adjacent to tree land＞alfalfa field adjacent to corn＞alfalfa field adjacent to fallow land.The alfalfa field adjacent to wheat also showed the highest evenness and dominance indices.The Shannon-Wiener index was higher at the edge of alfalfa fields than in their adjacent crop fields,indicating that the ground-dwelling carabid beetle community showed significant seasonal migration dynamics between the edge of alfalfa fields and their adjacent crop fields.The results indicated that different habitat interfaces,alfalfa mowing,irrigation,and other agricultural operations significantly affect the migration dynamics of ground-dwelling predators.