Journal of Environmental Biology

Community structure of earthworms under rubber plantations and

mixed forests in Tripura, India

Author Details

P.S. Chaudhuri

(Corresponding author)

Department of Zoology, Maharaja Bir Bikram College, Agartala - 799 004, India

e-mail: priya_1956@rediffmail.com

Sabyasachi Nath

Department of Zoology, Maharaja Bir Bikram College, Agartala - 799 004, India

Publication Data

Paper received:

10 March 2010

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Revised received:

14 September 2010

Accepted:

24 September 2010

Abstract

Studies on community structures of earthworms of rubber (Hevea brasiliensis) plantations and their adjacent mixed forests in West Tripura (India) revealed that both the studied sites harvoured 10 earthworm species. Nine species (Pontoscolex corethrurus, Kanchuria sp 1, Metaphire houlleti, Drawida papillifer papillifer, Drawida assamensis, Gordiodrilus elegans, Eutyphoeus assamensis, Eutyphoeus comillahnus and Eutyphoeus gigas) were common to both. While Octochaetona beatrix was found only in the rubber plantations, Dichogaster affinis was restricted to the mixed forest only. Earthworms were found mostly within 15 cm depth of soils having mean temperature of 27?C, moisture of 23%, pH of 4.57, organic matter of 1.34% and water holding capacity of 36%. Mean earthworm density in rubber plantations (115 ind. m^-2) was significantly higher (p = 0.003, t = 3.83) than that in the mixed forests (69 ind. m^-2) due to dominance of Pontoscolex corethrurus, an exotic species. Numbers of dominant species were two (P. corethrurus and D. assamensis) in the rubber plantations and five (P. corethrurus D. assamensis, D. papillifer papillifer, M. houlleti and Kanchuria sp 1) in the mixed forests. Compared to the mixed forests, significantly low (p<0.05) Shannon diversity index (H) and species evenness and high index of dominance in the rubber plantation were evaluated.

Key words

Earthworm community, Rubber plantation, Mixed forest, Dominance, Shannon-diversity index

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