International Journal of Marine Science 2015, Vol.5, No.51: 1-11
1
Research Article Open Access
Oligochaete Community Structure in Paddy fields and Channels in Kole paddy
fields, Vembanad Kole wetland, India
Vineetha S.
, 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
Corresponding author email
International Journal of Marine Science, 2015, Vol.5, No.51 doi
Received: 06 Jul., 2015
Accepted: 07 Aug, 2015
Published: 31 Aug., 2015
Copyright
©
2015 Vineetha et al., 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.
Preferred citation for this article
: 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): 1-11
Abstract
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/m
2
) than channels (891±1409 ind/m
2
) (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.
Keywords
Oligochaetes; Community structure; Kole wetlands; Paddy fields; Channels
Introduction
Wetlands are among the most productive, diverse and
ecologically sensitive ecosystems on Earth (Ghermandi
et al., 2008). Paddy fields are considered as man
managed temporary wetlands (Lupi et al., 2013). Rice
had been a major source of food for people since 2500
B.C. and paddy fields existed since the beginning of
organized agriculture (Edirisinghe et al., 2006).
Recently researchers opined that paddy fields could
surrogate the loss of natural wetlands due to its
biological diversity (Nathuhara, 2013).
Aquatic invertebrates are considered as key components
of paddy field fertility due to their significant role in
organic matter decomposition and nutrient translocation
(Roger et al
.
,
1987). Oligochaetes are known to be a
major component of the invertebrate fauna of flooded
paddy soils. Oligochaetes especially tubificid worms
increase bio available nutrients (nitrogen and phosphorus)
in submerged paddy soils, the release rates being
proportional to their densities (Roger et al.,
1987; Ito
and Hara, 2010). They promote nutrient mineralization
and suppress weed germination under laboratory
conditions (Kikuchi and Kurihara, 1977). Despite
their recognized contribution in maintaining soil
fertility in wetland paddy fields, little is known about
the densities, distribution dynamics, composition, and
ecology of field populations. Moreover, paddy fields
are not isolated but they are connected by channels or
drainage ditches which are small, shallow, line shaped
water bodies providing water for agricultural drainage
(Verdonschot et al., 2012). Recent studies pointed out
the importance of channels as reservoirs of invertebrate
biodiversity in agricultural areas emphasizing their
