Study On Characteristics Of Soil Fauna Community And Their Role In Ecological Restoration Alongside The Expressway In Inner Mongolia

The road construction will inevitably affect the area alongside the road. It needs scores of or even hundreds of years for bare slopes formed by constructing expressway to restore naturally. Man-made vegetation restoration can shorten the time of vegetation restoration and improve soil fertility on the slope alongside the road. Soil fauna are the important components of soil ecosystem. They have a significant contribution to soil formation and vegetation development.19775 soil fauna were captured from 11 habitats at slopes alongside Huji expressway in Zhuozi county, Inner Mongolia in both 2004 and 2007. The results showed that soil fauna belonged to 3 phyla, 6 classes, 20 orders, 3 suborders and 75 families. They were 994 macrofauna, 8301 meso-microfauna and 10480 nematodas. 17933 soil fauna were captured in 2004. There were 994 macrofauna, 7677 meso-microfauna and 9262 nematodas, which belonged to 3 phyla, 6 classes, 20 orders, 3 suborders and 74 families. 24 groups, that is, 1842 soil fauna were obtained from 4 habitats at slopes of man-made vegetation restoration alongside the Expressway in 2007. There were 23 groups, that is, 624 soil meso-microfauna and 1218 nematodas belonged to 2 phyla, 3 classes, 10 orders, 3 suborders and 16 families.Lumbricidae and Formicidae were the dominant groups of soil macrofauna community at slopes undamaged by the Expressway construction. Gamasida, Actinedida and Hypogastruridae were dominant groups of soil meso-microfauna at slopes undamaged by the Expressway construction. Nematoda, Acarina and Collembola dominated in the soil fauna community at bare slopes destroyed by the Expressway construction. Carabidae, Formicidae and Araneae dominated in the soil macrofauna community at slopes of natural vegetation restoration. The composition of soil meso-microfauna community was simple, dominated by Isotomidae, Gamasida and Actinedida there. The soil macrofauna community at slopes of man-made vegetation restoration was mainly composed of Coleoptera and Araneae.Gamasida, Actinedida and Isotomidae were the dominant groups of soil meso-microfauna community at slopes of man-made vegetation restoration. Three years later, the size of some soil macrofauna became smaller at slopes. It showed that the slopes of man-made vegetation restoration were degenerating with time.The groups of soil macrofauna at slopes undamaged by the Expressway construction were more than ones of other habitats. The groups and individuals of soil macrofauna at the slopes of natural vegetation restoration were more than ones at slopes of man-made vegetation restoration. The individuals of soil meso-microfauna at the slope of man-made vegetation restoration were the most of all.The vertical distribution of soil fauna was the individuals and groups descending with the depth of soil layers deepening. The individuals of soil fauna gathering the soil surface were more obvious than groups. The gathering soil surface of individuals and groups of soil fauna at bare slopes was not obvious. The change of soil fauna at slopes undamaged by the Expressway construction was not obvious. The time of man-made vegetation restoration had an important effect on the diversity of soil macrofauna and meso-microfauna. The indices of Shannon-Wiener, Pielou evenness and Margalef richness diversity of soil macrofauna and meso-microfauna at northwest slope of man-made vegetation restoration for one year were higher than those at southeast slope, while the index of Simpson dominance was opposite. The change of those diversity indices at slopes of man-made vegetation restoration that year was opposite to slopes of man-made vegetation restoration for one year. The changes of DG density-group and DIC index of soil macrofauna and meso-microfauna at the slopes of man-made vegetation restoration were similar. The values of DG density-group and DIC index of soil macrofauna and meso-microfauna at the slopes of man-made vegetation restoration were higher than those at the slopes without man-made vegetation restoration.The correlation of groups of soil macrofauna and meso-microfauna along expressway with soil environmental elements was not significant while the correlation of individuals of soil meso-microfauna with soil total N, total P, organic matter, pH value and moisture was significant. Canonical Correspondence Analysis two-dimensional scatter ordination diagram indicated that soil moisture had the greatest influence on soil meso-microfauna. The grey relevant coefficients of diversity of soil fauna community were high with soil pH value, total P, total K and soil moisture, suggesting that these soil factors were closely related to variation of soil fauna diversity.Man-made vegetation restoration promoted soil meso-microfauna to reproduce more. Their individuals increased quickly. But the groups and individuals of soil macrofauna were less and their diversity was low. Some of soil macrofauna began to intrude into expressway slope. Carnivore and Saprophyte became more and more with the vegetation and soil restoration. It made underground food web more complex, soil fauna community more diversity and stabile. The gradient slopes alongside the Expressway was relatively more abrupt. The out-soil was washed out by runoff gradually with time. Vegetation at slopes perished gradually. The groups and individuals of soil fauna decreased gradually. The difference of individuals of Lumbricidae, which was the dominant group of soil macrofauna, was noticeablely significant. So Lumbricidae has become one of biological index of evaluation of ecological restoration. It may improve the credibility of evaluation. The characteristics of soil fauna community could be considered as a bioindicator of evaluation of regional land sustainable use in the process of ecological restoration.