Diversity And Edge Effects Of Ground-dwelling Carabid Beetles Community And Their Responses To Alfalfa Mowing In Alfalfa Fields And Boundary Edges Of Their Adjacent Crops

Alfalfa industrialization scale development rapidly in recent years, the development zone of alfalfa planting area is expanding, xixia areas f Yinchuan city of helan mountain cattle ranches has a large area. Study using alfalfa and adjust measures to local conditions in different crops and intercropping system, by using ground trap investigation and comparison of the alfalfa field and different neighbor crop field ground beetle and spider species diversity, seasonal migration dynamic and space-time dynamic, in order to combine alfalfa field farming operations and habitat regulation to provide a scientific basis for natural protection strategy. The main results and conclusions are as follows:1、There was a obviously positive effect of the edge variation of carabid beetles.Shannon-Wiener diversity index number was:Ecotone>Wheat field>Alfalfa field, the diversity of Wheat and Alfalfa field reduced with the interface distance magnifying,there were significant differences among edge.The variation trends of abundance、individual number and Shannon-Wiener index number were same,but the survey time influenced the carabid beetles species and individual variation obviously in different distance edge.The space-time distribution dynamic of Chlaeniuspallipes individuals and carabid beetles Shannon-Wiener diversity showed that the agriculture activities obviously influenced Chlaeniuspallipes individuals and carabid beetles Shannon-Wiener diversity. Wheat field irrigation main effected the distribution change of Chlaeniuspallipes individuals,Alfalfa mowing resulted in the modification of carabid beetles Shannon-Wiener diversity in different plots.The research prompted that using the agriculture activities in different field could control transfer of natural enemies and control the outbreak of disaster pests.2、We designed 4 different habitat interfaces including alfalfa-wheat, alfalfa-cron, alfalfa-tree land and alfalfa-fallow grassland in Northwest of China. This article studied the species component, community diversity and seasonal dynamics. During the field research, a total of 9239 carabid beetles were collected, belonging to 21 species. In the edge of fields alfalfa,it showed that:(1)Abundanceindex was:alfalfa field adjacent to tree land> alfalfa field adjacent to wheat=alfalfa field adjacent to cron> alfalfa field adjacent to fallow grassland;(2) Shannon-Wiener diversity index was alfalfa field adjacent to wheat> alfalfa field adjacent to tree land> alfalfa field adjacent to cron> alfalfa field adjacent to fallowland; Shannon-Wiener diversity index make a comparison between the edge offields alfalfa and their adjacent crop fields,obviously lower than the former.Ground-dwelling carabidbeetles community exist a significant seasonal migration dynamics between the edge offields alfalfa and their adjacent crop fields.The different adjacent crop type, alfalfa mowing, irrigation and other fram operation significantly affect the degree of migration dynamics.3、Through the tree intercropping clover and alfalfa monoculture system natural enemy community structure and the dynamic change law of testing, the results show that the apple orchards intercropping field of alfalfa natural enemy species and quantity is higher than monoculture alfalfa field. Intercropping with monoculture mode characteristics of alfalfa field natural enemy community in temporal dynamics, apple orchard soil can improve the diversity and evenness of natural enemies, dominance has obvious changes in the process of time. Two kinds of cultivation mode after mowing, apple orchards intercropping field of alfalfa predators individual number and species has increased faster than monoculture alfalfa field. Planting alfalfa to increase vegetation diversity, orchard can not only provide orchard natural enemy insects with abundant nectariferous plant and good habitat habitat, effectively increase the orchard natural enemy species and quantity.