| Various factors influence the Hilly and Gully Loess Regions by geographical location, climate change, topographic and geomorphic conditions, and soil. In the process of agricultural civilization, the unreasonable way of utilization of resources led to great destruction of ecological environment. So, this region became one of fragile ecological environment and ecologically sensitive area in our country. After long-term exploration, the region puts forward a successful model of ecological management, and this model regards small watershed as the unified planning unit. Analyzing the quantitative evaluation on land use/cover change as well as its influence on landscape pattern and composition and spatial distribution of diversity of ground-dwelling beetles could help us in understanding the ecological functions of the whole basin landscape in the process of eco-restoration, which can provide scientific basis for restoring ecological environment, biodiversity conservation, reasonable resources utilization and ecological landscape planning in Hilly and Gully Loess Region under the background of development of ecological construction. In this paper, we selected Pengyang County as the study area, which has the representative of returning cropland to forest. By combining methods of remote sensing image interpretation, GIS analyses, field survey and simulation models, the landscape pattern of vegetation and variation of composition was analyzed, then this paper also studied the influences of ecological restoration on the diversity of ground-dwelling beetles (Coleoptera) and its relation with environmental factors in different habitats in Hilly and Gully Loess Regions. The main conclusions are as follows:(1) The change of land use/cover and spatial pattern of landscape in Pengyang County were analyzed by dynamic change of land use and landscape indices during1991to2010. 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. Build-up areas also increased accordingly with development of the county and rural industry. The change of landscape pattern was characterized as that the degree of landscape fragmentation, patches mixed distribution, diversity index and evenness index increased gradually and then decreased, the connectivity between patches decreased gradually and then increased, and landscape shape presented irregular. Regional development plans (returning farmland to forest/grass, afforestation of barren hills, grazing prohibition) was the driving force leading to the change of land use/cover and landscape after2000.(2) Based on data of field survey, community diversity of ground-dwelling beetles in six different habitats in Caomiao village was analyzed. The quantitative distribution of Pterostichus gebleri, Carabus brandti and Cicindela kaleea was similar, which distribution was higher in habitat with complex vegetation structure. Dolichus halensis was higher in ecological economic forest and level terraced field. Onthophagus gibbulus preferred shrub and grass mixed forest and tree and shrub mixed forest, and individuals were higher. Number of individuals, species richness, Shannon-Wiener diversity and Pielou evenness indices all showed significantly different among habitats. Cluster analysis showed that the community structures and habitats were similar among shrub and grass mixed forest, tree and shrub mixed forest, ecological fuel-wood forest, ecological economic forest as well as level terraced field. It was particularly more similar between ecological economic forest and level terraced field, and between tree and shrub mixed forest and ecological fuel-wood forest. Species composition of beetles in natural enclosed grassland had larger difference than other habitats, and there was considerably more variation about the composition of species..(3) The Generalized linear mixed model (GLMM) analysis was adopted to study the influence of habitat factors on the community diversity in different ecological restored habitats. Abundances, species richness, diversity index all displayed significantly different among habitats, while evenness was not significantly different. The effect of habitat factors on community diversity of ground-dwelling beetles was different. Cover of canopy layer and depth of leaf litter had a significant correlation with number of individuals, and biomass of herbs and soil water content had a highly significant correlation. Cover of shrubs, cover of leaf litter and biomass of herbs had significantly effects on species richness. Cover of leaf litter and biomass of herbs had a significant correlation with Shannon-Wiener diversity, and cover of herbs and depth of leaf litter had a significant correlation with Pielou evenness index. It was showed by canonical correspondence analysis (CCA) to the relationship between the composition of community of beetles and seven environmental factors, and depth of leaf litter, cover of canopy layer, cover of herbs and cover of leaf litter were the major factors affecting on the composition and spatial distribution of ground-dwelling beetles in different habitats.(4) Microhabitat selection of Carabid beetles was analyzed by Logistic regression model in six vegetation type in science-technology demonstration zone in Wangwa village. Number of individuals and diversity index of carabid all showed significantly different among vegetation types. Species richness in returning farmland to forest/grass was higher than other types, but not reached a significant level. Species richness estimation curves showed that four vegetation types were well sampled although the curve reached an asymptote only for the vegetation type of returning farmland to forest/grass and fish-scale pits. The Chao-1species-richness estimator showed that almost all species where captured in these two habitats, and most carabid species in natural restoration and level terraced field. In contrast, species richness at shrubs and economic fruit forest showed no indication of approaching an asymptote, and there was considerably more variation about the estimates. For Pterostichus gebleri, the type of fish-scale pits had the highest probability of occurrence, and the lowest in level terraced field. For Carabus brandti, the type of fish-scale pits, returning farmland to forest/grass and shrubs had higher probability of occurrence. The Occurrence probabilities of Dolichus halensis was highest in economic fruit forest and level terraced field, and was not incidence. Multiple logistic regression analyses displayed that biomass of herbs and soil water content were the critical habitat factor with microhabitat selection for Pterostichus gebleri. Cover of canopy, cover of shrubs, biomass of herbs and soil water content were the importantly environmental factors for Carabus brandti. Cover of shrubs, cover of herbs, depth of leaf litter, biomass of herbs and soil water content were key factors for Dolichus halensis. |
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