The Study On The Changes Of Soil Fauna Community In Decomposition Of Leymus Chinensis Litter In Inner Mongolia Typical Steppe

From June2010to October2012, using litter bag maethod, chosing three kinds of grasslands (i.e., the prohibited-grazing grassland, free-grazing grassland and sandy land) as sampling plots, we studied the changes of soil animal communities in the process of the decomposition of Leymus chinensis litter in Baiyinxile farm, Inner Mongolia tipical steppe. The main results as follows.1. In three kinds of sampling plots, we captured a total of93510soil animals, belonging to five phylums, eight classes, eight orders, and20groups. the dominant group was Nematoda, which made up91.83%of the total collected soil animals. And the common groups were Acarina and Collembola. What made up6.67%and1.16%of the total collected soil animals, respectivly.2. Th soil animal community composition and its total individual number in Leymus chinensis litter were not obviously influenced by the grazing activities. But the number of groups of soil animal community obviously decreased in free-grazing grassland. And the dominances of the main soil animal groups were changed. Also, the individual number of Collembola was decreased.3. The grazing activities had no significant effects on the Acarina community composition and its total individual number. Under the condition of grazing disturbance, the number of Acarina groups was increased. And the dominances of the main Acarina groups were changed.4. Under the condition of grazing disturbance, the Shannon-Wiener index (H’), Simpson dominance index (D) and Pielouevenness index(J) of Acarina community in Leymus chinensis litter were decreased. But the Margalef richness index (DMa) was increased. 5. Comparative to prohibited-grazing grassland, the dominance of the omnivorous and saprophagous soil arthropods were significantly decreased in free-grazing grassland. The dominance of phytophagous soil arthropods was significantly increased. And the dominance of predatory soil arthropods was no significantly changed.6. With the prolongation of the decomposition, all of the residues and the content of Leymus chinensis litter were significantly decreased in prohibited-grazing grassland. Grazing activities had no obviously effects on the changes of residues and the content of Leymus chinensis litter.Based on the above results, we can conclouded that the grazing activities had no significant effects on the composition of soil animal community in Leymus chinensis litter. But can result in the obviously changes of the number and the dominance of soil animal groups, and the biodiversity indice of Acarina and Collembola community. Also had no significant effects on the basic decomposition features of the Leymus chinensis litter.