Characteristics of soil fauna community in the Dongjiao coconut plantation ecosystem in Hainan, China

From July 2002 to July 2004, we investigated the soil fauna in the Dongjiao coconut plantation of Hainan Island. A total of 5,378 specimens were obtained. These species represented 4 phyla, 12 classes and 27 genera. The soil animal clusters are as follows: All major animal groups presented in a tropical rain forest are present in Dongjiao coconut plantation's soil community. The Dongjiao coconut plantation demonstrated the typical characteristics of a tropical soil animal community. The number of species and the diversity index (H) increase from the high latitude areas toward the equator; The dominance index (C) decreased from the high latitude areas toward the equator; the ratio of Acarina/Collembola and the percentage occurrence of increase along the declination of latitude; the occurrence of termites, a typical member of tropical community, varies from absent to present and a dramatic increase along the declination of latitude. Compared to primary tropical rainforests, the Dongjian coconut plantation community is relatively low in species diversity, and has a high dominance index and low diversity index. This may partially due to some characters of the plantation: singular tree species, monsoon climate, seashore location, high pH and salinity of the soil, soil moisture and other environmental factors. A seasonal change occurs in the community structure but is not obvious. Soil around human residences has a higher organic material content, and has higher counts of specimens and numbers of species, compared to other three sampling sites. Coconut production at locations around human residences is higher than at any other microhabitats. The high production is positively correlated with the richness of animal community in the soil.