The distribution of ground-active arthropod communities in aged lycium barbarum plantations in arid oasis region

An investigation on the community distribution of ground-active arthropods was carried on in Lycium barbarum plantations by the method of pitfall traps. The aged L. barbarum plantations of 1, 3, 5, 8, 10 years were selected as sampling sites at Zhongning County in arid oasis region of Ningxia, and the adjacent farmland served as the control. The results show that: (1) There were effect of aged plantations on the dominant index and group numbers of dominant groups and taxa groups, while there was considerable effect on the dominant index and group numbers of common groups. There were peaks of dominance index and group numbers of common group in 3- and 10-year-old plantations. In addition, there was an increasing-decreasing individual trend of predatory, phytophagous, omnivorous and saprophytic arthropods, and there was a peak in 8-, 3-, 3- and 8-year-old plantations, respectively. (2) There was a increasing-decreasing trend of individual and richness of ground-active arthropods along with aged plantations, with a peak in 8- and 3-year-old plantations, respectively. There was significantly lower Shannon-Wiener index and Simpson index of ground-active arthropods in 5- and 10-year-old plantations, respectively. (3) The results from RDA and pRDA analysis show that plant height, plant crown width and soil pH were the main environmental factors affecting the distribution of ground-active arthropod communities in aged L. barbarum plantations. It is concluded that there was a remarkable change of composition of ground-active arthropod communities during the growth process of L. barbarum plantations converted from the cropland in arid oasis region of Ningxia; especially the composition of common groups showed strong changes. In addition, the individual and richness of ground-active arthropods decreased from the croplands toward aged L. barbarum plantations, whereas there was a high di-versity of ground-active arthropods during the period between 3- and 8-year-old L. barbarum plantations.