Abstract: To study the effects of altitude on tardigrade community structure,an investigation was made on the Mount Wutai located at the north slope of Qinling Mountains.Three areas were selected at different altitudes,and 45 sampling plots were investigated.A total of 919 individuals of tardigrade belonging to 11 species,7 genera,3 families,2 orders and 2 classes,were obtained,with an average density of 816.89 individuals·m^-2.The individuals of Macrobiotus hufelandi and M.harmsworthi occupied 92.93% of the whole collection,composing the dominant groups.Simpson index,Shannon-Wiener diversity,Pielou evenness index and improved Hill index were used to evaluate the characters of tardigrade community structure in each sampling area,and Jaccard index was used to analyze the similarity between different communities.The results indicated that altitude had certain effects on the tardigrade community structure.The density,especially the population density of the dominant species,and the number of the dominant species decreased with decreasing altitude.The variation trend of species diversity was in order of medium altitude>lower altitude>higher altitude,while that of the dominant degree of community was on the contrary.The communities shared very lower similarity at different altitudes.

Key words: Sub-alpine forest, Spatial pattern, Restoration, Topography, Regeneration