|Other Abstract||Enchytraeidae is one of the most specious clitellata groups. To date, all some 650 valid species of 31 genera are known. These tiny potworms are a critical component of terrestrial ecosystems, and play key roles in regulating ecosystem processes of decomposition and nutrient mineralization. In China, however, because these worms were ignored until the late twenties, there taxonomy as well as their biology has become a subject of study only recently. Compared to the other microdrile oligochaetes, related researches on Enchytraeidae started late and lagged far behind.
In this paper, a serial surveys were carried out in Yunnan, Hunan, Hubei, Guizhou, Shangdong, Jilin Provinces and Chongqing Municipality. More than 50 terrestrial species were identified. On the basis of this, the faunal composition, biodiversity and distribution of enchytraeids were discussed thoroughly in Changbai Mountain. In addition, the relationships between enchytraeids and environmental factors were discussed. The main results are summarized as follows:
A taxonomic catalogue of Enchytraeidae from China was listed according to Nielsen & Christensen (1959, 1961, 1963) and Schemlz (2003) classification systems and the previous research findings. 81 taxa belonging to 17 genera were presented. Further, 8 new species: Bryodrilus fuscistriatus; Fridericia dianchiensis; Oconnorella cheni; Oconnorella globula; Fridericia liangi; Mesenchytraeus anisodiverticulus; Mesenchytraeus megachaetus; Mesenchytraeus monodiverticulus, 21 new records species and one new record genus (Cognettia) were added to the catalogue and were fully described and illustrated by drawings and pictures.
Quantitative researches concentrated on the northern slope of Changbai Mountain. The distribution of enchytraeid communities and biodiversities in this region were investigated. 29 species belonging to 9 genera were found. The richnest genera were Fridericia (8 species), Henlea (6) and Mesenchytraeus (5). The predominant groups were Mesenchytraeus (38.8% of the total abundance), Henlea (28.3%), Fridericia (19.7%) and Bryodrilus (6.9%). The results suggested that types of plants and altitude play an important role in shaping the community structure and species divesities of enchytraeid. Along with the increased altitude, the density and richness of Enchytraeid showed a decreased trend.
Constrained ordination analysis (CCA) was applied to identify the relationship between enchytraeid community structures and environmental factors (including 3 basin variables and 11 habitat variables) in 18 sampling sites. The results showed that the depth of litter layer, altitude, the content of K and soil moisture were the most important factors influenced enchytraeid community structures, and explained ca. 43% of the total variations. In general, the structure and distribution of enchytraeids in the Changbai Mountain were mainly controled by habitat factors other than regional parameters.|