Abstract: The co-occurrence of soil fauna communities at different altitudes may reflect at some extent the relationships a-mong communities, their coexistence, and the replacement of species along the altitude gradient.The continuous or disjunctive distribution of different species along altitude gradient not only reflected the environment variation at altitude gradient, but also the biological and ecological spatiality as well as the adaptability of species.The northern slope of Changbai Moutain has not only a high diversity in soil fauna types and species, but also a high variation of diversity pattern along the altitude gradient, which is a perfect transect for the research of biodiversity and gradient patterns.From 550m to 2560m on the northern slope of Changbai Mountain, twenty-two plots were investigated with an interval of 100m in altitude.By using Jaccard index, the co-occurrence of soil fauna communities at different altitudes was analyzed.For the species of different life forms or for all the species as a whole, the co-occurrence of soil faunae between neighboring communities was the highest, except for that between different soil fauna types.The peak and valley values of the co-occurrence of soil fauna communities along altitude gradient were matched with their gradient patterns, and the co-occurrence of soil faunae at different layers or all of the soil fauna communities were decreased with increasing altitude difference.

Key words: Changbai Mountain, Co-occurrence of species, Soil fauna community, Altitude gradient