Journal of Environmental Biology

Species diversity and community characteristics of earthworms in managed and degraded tea plantations of Tripura

S.K.S. Jamatia and P.S. Chaudhuri*

Earthworm Research Laboratory, Department of Zoology, Tripura University (A Central University), Suryamaninagar-799 022, India

*Corresponding Author E-mail: priya_1956@rediffmail.com???????????

Key words

Anthropogenic interferences

Diversity indices

Earthworm diversity

Exotic earthworms

Tea plantation

Publication Data

Paper received : 21.07.2016???????

Revised received : 05.01.2017???

Re-revised received : 08.04.2017

Accepted : 10.05.2017???????????

Abstract

Aim: Tea (Camelli sinensis) is an economically important and intensively managed cash crop in the north-east India. As earthworms represent the highest soil biomass and are good indicators of soil health, the main objective of the study was to find out the impact of conventional management practices (anthropogenic interference) on earthworm biodiversity and relative density of exotic and native species in tea agro-ecosystem.

Methodology: Earthworms were collected adopting TBSF soil monolith (25 cm x 25 cm x 40 cm) by digging and hand-sorting method in the managed tea plantation and degraded tea plantation of Tripura. Physico-chemical parameters of soils (temperature, moisture, organic matter, pH), biological parameters viz., earthworm density, biomass, relative density and ecological parameters (indices of diversity, dominance) were measured.? ??????

Results: Anthropogenic interferences had greatly influenced the earthworm diversity in tea plantations. Out of total seventeen earthworm species, thirteen and fifteen earthworm species were recorded in the managed tea plantation and degraded tea plantation, respectively. Density (56 ind. m^-2) and biomass (27 g m^-2) of exotic species in managed tea plantation were significantly higher (p<0.01) than those of degraded tea plantation (23 ind. m^-2, 17 g m^-2). Exotic species, Pontoscolex corethrurus and native species, Drawida assamensis were the dominant species of managed tea plantation and degraded tea plantation. Significantly higher (p<0.01) index of dominance (0.73), lower diversity index (0.66) and lower species richness (0.31) were observed in managed tea plantation compared to those of degraded tea plantation (dominance 0.37, diversity 0.89, species richness 0.77) ?????????

Interpretation: Low earthworm diversity with high dominance of exotic species in managed tea plantation was due to high anthropogenic activities that favoured the exotic earthworm species over native species.

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