| Desert ecosystem is one of the most vulnerable systems in terrestrial ecosystems, and in which biodiversity loss is more serious. There are very important to study and protect on the biodiversity in desert ecosystem. Artemisia desertorum is one of important of sand-fixing pioneer plants widely distributed in the desert grasslands in Ningxia of China, and to study the emergence and ecology of injurious insect on Artemisia desertorum is very important significance on sand prevention and control and grassland protection. So we taked experimental area of Artemisia desertorum in the Desert ecosystem, to study on diversity of soil animal and population ecology of the pests Chrysolina aeruginosa damaged on Artemisia desertorum. The main results conclusions and conclusions results are as follows:1) Studied on relationships of the species diversity of soil animal in different desert habitats with environmental factors shows:In dominant groups of three habitats soil animal communities were Carabidae, Staphylinidae and Cicadellidae imagines. Species richness, evenness and diversity indices of Desert Seppe(DS) were significant higher than Atificial Sand-fixation Landand(AS) and Shifting Semi-shifting Land(SL)(P<0.05), Evenness and diversity index of AS were the highest, while dominance index was significantly higher than DS and SL (P<0.05). The density of soil animal, evenness index, diversity index, dominance index were highest on 0-5 cm of soil depth. Compared to the same soil layer, density of soil animal, richness and diversity index showed DS> SL> AS which turned out that in succession of SL to DS, the density and the number of soil animal were increased. Redundancy Analysis (RDA) showed that soil moisture content, organic carbon, total nitrogen, total phosphorus, and plant diversity reaction were influence the diversity of soil animal. Partial correlation analysis showed that the main factors affecting the soil animal diversity of surface soil were soil temperature, soil water content, organic carbon, total nitrogen and plant diversity index, and affeced the soil animal diversity of deep soil layer were soil water content and organic carbon.2) Study on species diversity of ground-dwelling beetles and its relationship in droughty manually-fixed sand land (DMFSL), artificial vegetation of subhumid sandy land(AVSSL) and artificial vegetation of droughty sandy land (AVDSL), the results showed that a total of 4778 ground-dwelling beetle specimens were collected by pitfall trapping method, and there were 50 species belonging to 11 families 30 genera. Tenebrionidae and Curculionidae can be considered as dominant families in the study area. The species numbers, species richness index, diversity index were the most in AVSSL. The individuals was most in AVDSL, but the species numbers, richness index, diversity index were the lowest. There were 16 common species in the three different habitats, rare species achieved in total species. Rarefaction curves based on species and individuals showed that the species richness is the highest in AVSSL, and wsa the lowest in theAVDSL. The desert soil moisture and vegetation were the main reason that affected the community diversity of ground-dwelling beetles. The canonical correspondence analysis (CCA) results showed that soil moisture, vegetation density and vegetation coverage were the main factors causing beetles diversity differences.3) Studied on the relationship between spatial distribution pattern of Chrysolina aeruginosa and environmental factors indicate that in different habitat the population of Chrysolina aeruginosa in the middle ten day in August is most. The Chrysolina aeruginosa are distributed in above middle of Artemisia desertorum. The Correlation Analysis showed the population number of Chrysolina aeruginosa that is closely related with the density of Artemisia desertorum、altitude and soil type, and the human disturbance is a important factors to affect it.4) A study on the damage rate of Chrysolina aeruginosa suggests that there are positive correlation between damage rate and dominance of Chrysolina aeruginosa; and are negative correlation with density and coverage of Artemisia desertorum.The damage rate of Artemisia desertorum has closely related with the shape and length of the patch, the edge effect decrease the damage rate of Chrysolina aeruginosa.5) A study on population dispersal of Chrysolina aeruginosa based on marketing-recapture method shows that the dispersal scope are negative correlation with time, it is from 0 to 900 centimeter and the difference was significant(F8,27=5.825,P=0.0002), but it mainly varies around the center from 0 to 100 centimeter, and the difference was significant between the different dispersal distances (F3,7=3.842, P=0.0077). The dispersal usually starts in the north and northeast. The dispersal distance and position of Chrysolina aeruginosa are closely related with spaces distribution characteristics of Artemisia desertorum, dispersal position of Chrysolina aeruginosa related with wind direction, the dispersal number which up the wind least than down the wind. |
PDF Full Text Request