Seasonal distribution and abundance of earthworms (Annelida: Oligochaeta) in relation to the edaphic factors around Udupi Power Corporation Limited (UPCL), Udupi District, southwestern coast of India

摘要

Seasonal distribution and abundance of four species of earthworms belonging to three families—Rhinodrilidae ( Pontoscolex corethrurus ), Megascolecidae ( Megascolex konkanensis and Metaphire houlleti ) and Octochaetidae ( Karmiella karnatakensis )—were studied in three habitats (residential, agricultural and forest) along with edaphic factors around Udupi Power Corporation Limited (UPCL), Karnataka, India between September 2014 and August 2016. Among the four species, P. corethrurus was collected throughout the year and was most abundant in residential habitats such as colacasia garden, coconut and banana pits. M. konkanensis was collected from coconut plantations, banana plantations and forest soil during monsoon and post-monsoon periods. M. houlleti was collected from manure heaps, coconut and banana pits of residential habitat, coconut plantations and forest soil. K. karnatakensis was collected from garden soil in residential habitat during the post-monsoon period, coconut plantations and soil mixed with forest leaf litter during monsoon and post-monsoon periods. The soil temperature differ significantly during different seasons in residential (P= 0.01) and agricultural (P=0.03) habitats whereas moisture shows highly significant difference in agricultural habitat (P=0.00037) during different seasons. P. corethrurus showed positive correlation with organic carbon during pre-monsoon and C/N ratio during monsoon in the residential habitat. It shows negative correlation with pH during the monsoon period. M. houlleti showed positive correlation with organic carbon in residential habitat during the pre-monsoon and in forest habitat during monsoon periods. M. konkanensis showed positive correlation with electrical conductivity in agricultural habitats during monsoon period. K. karnatakensis showed positive correlation with moisture during monsoon and with C/N ratio during post-monsoon period in forest habitats.