Effects Of Desert Landscape Habitat Fragmentation On The Ground-dwelling Beetle Diversity In Ningxia Lingwu Baijitan National Nature Reserve

The Baijitan National Nature Reserve of Ningxia is one of the typical nature reserve with desert ecosystem as its main protected object. This study was based on theories of the traditional insect sistematics, ecology, and the latest landscape ecology, using pitfall trap method to investigate the species composition and quantity distribution of ground-dwelling beetles in several representative plots of this protected area, to explore the relationship between environmental factors and community diversity of desert beetle, the impact of habitat fragmentation on the ground beetle diversity and so on. The main conclusions are as follows:(1) The sand-fixation grassland plantation (TSH1～TSH11 plots), the caragana plantation (TSH12 plot), the desert steppe (TSH13 and TSH14 plots) and so has a certain representation of 14 plots were selected in the middle of protected area, from May to October 2013and April 2014, Pitfall traps were used to collect ground-dwelling beetle,collected once a mid-month, a total of 3385 beetles were collected in this study, by classification and identification,these beetles belong to 16 families,57 genera and 80 species. Which Tenebrionidae and Melolonthidae were the absolute dominant group of the ground-dwelling beetles in this region. Anatolica mucronata and Microdera kraatz alashanica were the dominant species. Single factor variance analysis showed that the number of species (F= 1.749, P=0.0654)of 14 plots did not differ significantly, the number of species in the desert steppe was the largest, followed by the sand-fixation grassland plantation, and the caragana plantation was the least. Number of individuals(F=2.1, P=0.0032) were significantly different in three habitats, the number of individuals from higher to lower were the desert steppe, the sand-fixation grassland plantation and the caragana plantation. Community diversity analysis showed that three different habitats of species richness was the highest in the desert steppe, followed by the sand-fixation grassland plantation, and the caragana plantation was the least. Simpson dominance index was the highest in the caragana plantation followed by the sand-fixation grassland plantation, and the desert steppe was the least. Shannon-Wiener diversity index was the highest in the sand-fixation grassland plantation, followed by the caragana plantation, and the desert steppe was the least.evenness index was the highest in caragana plantation, followed by the sand-fixation grassland plantation, the desert steppe was the least. For 14 plots, species richness was the highest in TSH4 plot (1.82), TSH13 plot was higher (1.69) and TSH11 plot was the lowest (0.70). Simpson dominance index was the highest in TSH1 plot(0.78), TSH11 plots was the lowest (0.29). Shannon-Wiener diversity index was the highest in TSH4 plot (1.37), TSH11 plot was the lowest (0.56). evenness index was the highest in TSH12 plot (0.85), followed by the TSH1 plot (0.84), the TSH11 plots was the lowest (0.32). Beetles and canonical correspondence analysis(CCA) showed that the relationship between environmental factors on the ground beetle that big impact environmental factors are mainly vegetation density (r=0.6340), plant biomass (PB) (r=0.4312), soil water content (r=0.2736), and soil pH (r=0.1159). Impact of changes in habitat for ground beetle species diversity is obvious. Differences landscape matrix conditions are the main factors affecting the occurrence of ground beetles.(2) Selecting 17 patches of landscape artificial sand-fixing plots from May to July in 2013 and 2014, Pitfall traps were used to collect ground-dwelling beetle,collected once a mid-month, a total of 3444 beetles were collected in this study, these beetles belong to 13 families,39 genera and 56 species. Tenebrionidae and Melolonthidae were the dominant groups. Single factor variance analysis showed that the species composition, the number of individuals affected by plaque area was significantly diversity index, species richness exhibited increases plaque area gradually increasing. Population density and patch density index of ground beetles (r0.9835) were positively correlated with the desert patch fragmentation index (r=-0.8872), the shape of the landscape fragmentation index 0=-0.9876), desert landscape shape index fragmentation (r=-0.9773), interior habitat area landscape fragmentation index (r=-0.9896) showed a negative correlation. Patches of desert landscape fragmentation pattern of beetle populations have significantly inhibited plaque area wes reduced, increasing the degree of habitat fragmentation, reduced ground beetle diversity.