DIVERSITY AND DISTRIBUTION OF EARTHWORMS IN A SUBTROPICAL FOREST ECOSYSTEM OF MOKOKCHUNG DISTRICT, NAGALAND, INDIA

Abstract

A comparative study on diversity and distribution of earthworms along with the various physico-chemical factors
influencing their distribution was carried out in three sites i.e. natural reserve forest, plantation area and jhum
fallow area of a subtropical hill forest ecosystem located in Mingkong area of Mokokchung district, Nagaland,
India. Seven species of earthworms representing the three families Moniligastridae, Octochaetidae and
Megascolecidae were recorded during the study period of 2013-15. The earthworm density (individuals) and
biomass (weight) in the study sites were found to be maximum during the monsoon season viz., plantation area
(195.59±5.36 m-2, 96.23±2.50 gm-2) and fallow land (173.48±4.54 m-2, 138.24±3.34 gm -2) however, in the
natural forest ecosystem though the density was highest during monsoon (257.71±4.87 m-2), biomass record was
maximum during the pre-monsoon season (239.33±3.43 gm-2). The highest annual density (609.68±11.33 m-2)
and biomass (549.87±9.05 gm-2) was recorded in the reserve forest ecosystem. Variation of earthworm density
and diversity in all the three study sites were found to be affected by different microclimatic and soil physicochemical factors such as soil moisture content, soil temperature, bulk density and nutrient content viz. organic
carbon, and total nitrogen.