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Studies have shown that multiple agricultural structures could affect the dynamics and distribution of aphids,parasitoids and hyperparasitoid systems.In this article,we designed two spatial scales of agricultural structure and analyzed the affects of different agricultural landscape factors for wheat aphids,parasitoids and hyper parasitoids in two spatial scales in wheat fields in Ningxia Province,P.R.China.Through stepwise regression methods,we screened key landscape factors in two spatial scales that influenced wheat aphids,parasitoids and hyperparasitoids in different population growth periods.We then stimulated distribution and sequence of wheat aphid,parasitoids and hyperparasitoids with CANOCO software.As a result,we were able to study the influence of the landscape matrix and composition of surrounding landscapes on the proliferation of aphids,parasitoids and hyperparasitoids and analyze the dynamics of wheat aphids,parasitoids,hyper parasitoids and seven landscape factors(wheat fields,non-wheat crop fields,grassland,tree lands,bare area,plastic house,and other lands) in 95 fields over a two year periods(2009—2010).The composition and texture of the surrounding landscape were derived from high altitude photographs.Seven landscape variables,aggregated at two spatial scales ranging from 31400 m2 to 125600 m2,were measured from aerial photographs.Regression models incorporating within-field and seven landscape factors accounted for 37%—58% of the variety of aphids,parasitoids and hyperparasitoids in the wheat fields.Result showed a correlation between landscape factors and dynamics and distribution of aphids,parasitoids and hyperparasitoids.In immigration periods,bare areas greatly enhanced the immigration numbers of two wheat aphids while the employment of a plastic greenhouse sharply decreased the immigration number.In growth periods,grasslands and tree lands accelerated the population growth rate of two aphids species.As plastic greenhouse suppressed the population growth rate of aphids,however,plastic greenhouses,grasslands and tree lands accelerated the population growth rate of parasitoids(aphidiidae),which was greatly restrained by non-wheat crop habitat.Grasslands and tree lands accelerated the population growth rate of hyperparasitoids.Thus,we concluded that,in stable periods,the maximum population density was highest in the agricultural landscapes with the greatest percent of bare area.Both grasslands and tree lands increased the maximum population density of parasitoids and hyperparasitoids.The results in two spatial scales were similar.Overall,parasitoids and hyperparasitoids abundance and species diversity increased with increasing bare area in wheat fields and with increasing amounts of non-cultivated lands and increasing patchiness in the surrounding landscape.We attributed the discrepancy between the response of these parasotoids and hyperparasotoids to landscape factors in relation to differences in mophological and life history characteristics.The specific composition of parasitoid and hyperparasitoid assemblaged significantly alters parasitism at different levels of agricultural landscape composition.Future studies should evaluate more plants in landscape,non-crop herbivore densities and allot more time to the impact of agricultural landscapes on diversity and function parasitoid and hyperparasitoid.Major areas of study covered the construction and design of agricultural structure in successive spatial-temporal scale,which enhanced activity and predation of natural enemies in agricultural landscape and suppressed the pest population to the greatest extent.

The quantitative evaluation on land use/cover change as well as its influence on landscape pattern under the background of returning grain plots to forestry is significant to the sustainable utilization of land resources and ecological environment reconstruction in the southern Ningxia. Based on multi-temporal remote sensing data from four periods of Landsat TM/ETM, and combination of ecological quantity analytical method with GIS, the change of land use/cover and landscape pattern in Pengyang County of Ningxia Province were analyzed. The conclusions showed that the amount of each land use type was changed with different degrees, the area of forest/grass land increased, while farmland and unused land decreased. The change of landscape pattern was characterized as that the degree of landscape fragmentation, mixed distribution of patches, diversity index and evenness index increased gradually and then decreased, the connectivity between patches decreased gradually and then increased, and landscape shape presented irregular.

The aim of this study was to probe into changes in diversity of ground-dwelling beetles (Coleoptera) and their relation to environmental variables within restored habitats in the hill and gully area of Loess Plateau, Ningxia Hui Autonomous Region, China. An investigation of ground-dwelling beetle communities was carried out using pitfall traps in six habitats including shrub/grassland, tree/shrub mix, fuel-wood forest, naturally restored grassland, plantation forest, and level terraced field in July and August, 2013. We found that species richness and abundance of individual ground-dwelling beetles was higher (P