Vineetha Saraswathy , Bijoy Nandan S. , Rakhi Gopalan K.P.

Department of Marine Biology, Microbiology & Biochemistry, School of Marine Sciences, Cochin University of Science and Technology, Fine Arts Avenue, Kochi-682016, Kerala, India
Author    Correspondence author
International Journal of Marine Science, 2015, Vol. 5, No. 51   doi: 10.5376/ijms.2015.05.0051
Received: 06 Jul., 2015    Accepted: 07 Aug., 2015    Published: 07 Sep., 2015

This is an open access article published under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Vineetha S., Bijoy Nandan S. and Rakhi Gopalan K.P., 2015, Oligochaete Community Structure in Paddy fields and Channels in Kole paddy fields, Vembanad Kole wetland, India, International Journal of Marine Science, 5(51): 1-10 (doi: 10.5376/ijms.2015.05.0051)

Benthic invertebrates including oligochaetes are important components of paddy field fertility due to its significant role in organic matter decomposition and nutrient translocation, but have been studied less. The oligochaete community structure in paddy fields and channels/agricultural ditches of Kole wetlands (a part of Vemband Kole wetlands, a Ramsar site on the south west coast of India) was studied during Punja (summer crop season- January to May 2011). The benthic fauna belonged to the phyla Mollusca, Annelida and Arthropoda. Fifteen oligochaete species of family Naididae, Tubificidae and Lumbriculidae were identified. Seven taxa; Aulodrilus pluriseta, Aulodrilus sp., Aulodrilus piguiti, Branchiodrilus semperi, Stephensonia trivandriana, Pristinella minuta and Pristinella  jenkinae were present both in the paddy fields and channels. Six species; Allonais gwaliorensis, Allonais paraguensis, Dero zeylanica, Pristinella accuminata, Pristina menoni, Lumbriculus variegates were exclusively found in the channels and two taxa; Branchiodrilus hortensis, Homochaeta sp. exclusively in the paddy fields. ANOSIM results revealed a similarity in oligochaete composition among paddy fields and channels (Global R=0.19, p>0.05); the lack of environmental specialization in aquatic oligochaetes could be a reason for this. Abundance significantly varied among them, a lower abundance observed in paddy fields (102±161 ind/m²) than channels (891±1409 ind/m²) (ANOVA F_{1, 24}=6.02, p<0.05). Less habitable area in paddy field due to the compartmented substratum by paddy root structures resulted in a reduced abundance in paddy fields. Species richness and diversity showed no significant variation but evenness showed a significant variation between paddy fields and channels (ANOVA F_{1, 8}=10.40, p<0.05). As oligochaetes are characterized by less dispersal and migration ability evenness component would have been more sensitive than other diversity indices.

Oligochaetes; Community structure; Kole wetlands; Paddy fields; Channels