The diversity and distribution of terrestrial earthworms in Sakaerat Environmental Research Station and adjacent areas, Nakhon Ratchasima, Thailand.

The distributions of terrestrial earthworms were studied in the Sakaerat Environmental Research Station (SERS) and adjacent areas. The earthworms and soil samples were collected in the same 30×30×30 cm sampling sites from four vegetation types (dry evergreen forest, dry dipterocarp forest, forest plantation and grassland) four agricultural lands (rice paddy, sugarcane, cassava and mango) and three types of residential areas (household, SERS building area and Silvicultural Research Station area). The digging and hand sorting method was used to collect the earthworms, three times during rainy season (June, August and October) in 2006. Identification of terrestrial earthworms was based on external and internal morphology. Nineteen species of five families were found in studied areas. Pontoscolex corethrurus, the only member of the Glossoscolecidae, had the highest population density followed, by 11 species of Megascolecidae, three species of Moniligastridae, three species of Octochaetidae and finally, Gordiodrilus elegans, the only species of Ocnerodrilidae, was found in only a household area. Most earthworms collected were adults. Highest population densities were found in residential areas followed by agricultural lands and forest types. The earthworm density was highly significant different in October. The highest density was in SERS (611.1 ind/m ) 2 and the lowest was in DIF (61.1 ind/m ). The highest species diversity was 11 in SRS but the highest diversity 2 index was 1.71 in rice paddy.