Effects of coal mining subsidence on the community structure of soil macro-fauna in central China

Soil fauna, as an important form of soil ecosystem, can be used as a proxy for soil ecology in characterizing eco-environmental changes. Soil macro-fauna community structures in different soil ecosystems in coal mining subsidence areas of central China were investigated in the summer of 2007. A total of 477 individual soil macro-fauna were hand-collected in the field and classified into 22 families, 15 orders, 7 classes and 3 phyla. The dominant groups were araneae, coleoptera, orthoptera and hymenoptera, amounting for 83.64% of total collected macro-fauna. About four common groups accounted for 13.22% of the total fauna. Results showed a significant effect of coal mining subsidence on the individual density and group number of soil macro-fauna communities. Individual density significantly increased with increasing depth of subsidence. Change in soil eco-environment of subsidence areas triggered local migration of soil macro-fauna. Jaccard coefficient analysis showed high similarity among soil macro-fauna communities in 2 m, 4 m and 6 m depths. The lowest observed similarity was between common farmlands and bed soils of subsidence regions. The findings suggested that soil macro-fauna communities were strongly influenced by land subsidence. It was important to introduce soil macro-fauna to improve soil biological quality and assessment in subsidence farmlands.