| Due to High intensity agricultural development, the natural and semi-natural habitats in agricultural landscape will continue to reduce, which makes many of the non farmland biological lose their habitats and food source and shelter, exacerbated the biodiversity loss in farmland system.Together with the highly intensive management, human disturbance intensity increasing, Further led to the reduction of agricultural landscape heterogeneity. The agricultural landscape patch to maintain diversity and stability of biological diversity can not be ignored. Among them, the natural and semi-natural habitats in agricultural landscape not only provide shelter, Species source, habitats and food sources for the biology, but also play an important role in maintaining the biodiversity of agricultural landscapes. Therefore, it is of great significance to maintain the natural and semi-natural habitats in the agricultural landscape for biodiversity conservation.To explore the relationships between landscape heterogeneity and soil meso- and microfaunal communities in typical agricultural landscapes, we established a study area in Fengqiu County, Henan Province, which is a typical agricultural region in the lower reaches of the Yellow River. We established different buffer radii(25 m, 50 m, 100 m, 150 m, 200 m, and 250 m) at the plot scale, based on a multi-scale(plot, habitat, and field) approach. We combined soil faunal diversity data from 31 sampling plots in the study area. We used the landscape index of CONTAJ as an a priori landscape index to determine landscape heterogeneity levels, including high, medium, and low landscape heterogeneity. Moreover, at the habitat scale, we selected farmland and woodland in each plot as habitats. At the field scale, soil sampling rings and Tullgren funnels were used to obtain soil meso- and microfauna from the center and edge of the farmland and woodland habitats in the spring, summer, autumn, winter of 2014 and the spring of 2015. In addition, the effects of scale on the diversity of soil meso- and microfauna were analyzed using a multivariable ANOVA at plot, habitat, and field scales. Finally using the model in the Canoco 4.5 correspondence analysis(CCA) explore eight environmental factors(Soil moisture content, soil bulk density, pH, available phosphorus, soil organic matter, total nitrogen, activated carbon and plant cover, height, richness) affect soil faunal communities distribution.Research shows that:(1) A total of 10951 soil faunal individuals belonging to 57 classes were identified in the spring, summer, autumn and winter seasons of 2014. The dominant groups included Oribatida, Actinedida, Staphilinidae and Cydnidae. Entomobryidae, Isotomidae, Poduridae, Formicidae, Diptera larvae, Silphidae, Scydmaenidae, Nitidulidae, Scraptidae, Coleoptera larvae and Cicadellidae were common groups. The results indicated that different habitats and fields contained different species abundances of soil meso- and microfauna. For example, the species diversity indices including species richness, Shannon index, and Simpson index were the highest at the edge of the farmland, but the lowest in the center of the woodland. Animal diversity in the soil indicated that, except that the species richness index, Shannon index and Simpson diversity index of farmland edge were significantly higher than that of woodland center, there were no significant differences among other diversity indices.(2) In sudy site, the trend of seasonal dynamic of the total individual number and group number of soil fauna were consistent, which showed that soil animals were the most abundant in summer but the least in winter. For biological diversity, in the spring, the species richness of soil fauna was significantly higher than that of the woodland center and the edge of the forest land, but other diversity indices was not significantly different between the center and the edge of the woodland and the center and the edge of the farmland. In the summer and autumn, the soil animal diversity indices were not significantly different between the center and the edge of the woodland and the center and the edge of the farmland. But in the winter, the species richness index and Shannon index of woodland edge were significantly higher than that of farmland center, but other diversity indices was not significantly different between the center and the edge of the woodland and the center and the edge of the farmland.For the same habitat in different seasons, the soil fauna diversity indices of farmland center, farmland edge, woodland center and woodland edge were significantly different in spring, summer, autumn and winter. For the center and the edge of the farmland, the individual number, species richness index, Shannon index and Simpson diversity index of soil fauna were all shown as the most abundant in summer and the lowest in winter. For the center of the woodland, the individual number, species richness index, Shannon index and Simpson diversity index of soil fauna were all shown as the most abundant in summer and the lowest in spring. For the edge of the woodland, the summer had the greatest individual number of soil fauna, whereas the lowest abundance occurred in the winter. Furthermore, species diversity indices including species richness, Shannon index, and Simpson index were the highest in the summer, but the lowest in the spring.The variance analysis was performed on the individual number, species richness index, Shannon index and Simpson diversity index of the farmland edge, the farmland center, the woodland center and the woodland edge among different interannual. The result showed that, in addition to the center woodland and woodland edge of the species richness index, Shannon index and Simpson diversity index in the spring of 2015 were significantly higher than that of spring 2014, other indices at interannual had no significant difference.We discussed the seasonal trend of soil moisture content, soil temperature, the height and coverage of the surface vegetation and soil faunal diversity indices including species richness and Shannon index. The result showed that the richness and Shannon-wiener diversity index of soil fauna varied with the change of soil moisture content, soil temperature, and the height and coverage of vegetation.(3) Although there was no significant effect among different landscape heterogeneity levels at the plot scale, the effect of landscape heterogeneity index on the soil fauna was significant at the 25 m buffer radius. However the effects of habitat scale on the soil faunal communities were most significant among the three scales(plot, habitat, and field). At the habitat scale, It was showed by canonical correspondence analysis(CCA) to the relationship between the composition of soil faunal communities and ten environmental factors, that the soil moisture, the soil moisture content, the plant coverage and plant height were the major factors affecting on the composition and spatial of soil fauna. |
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