Species composition and abundance of rotifers (Rotifera: Eurotatoria) in Thrissur Kole wetland, Kerala, India.

Abstract

Kole Wetlands are the major freshwater wetlands of Kerala, which spread over Thrissur and Malappuram districts of Kerala. They are the most productive and threatened wetlands in Kerala. Zooplanktons are heterotrophic animals; floating in the water and act as indicators for water quality. The Rotifers form a major portion of the freshwater zooplankton, serve as an important source of food for many larger aquatic organisms, and an integral part of the aquatic food web. In this context, the study on biodiversity and the abundance of rotifers was carried out from November 2017 to October 2019 from different stations of Trissur Kole wetlands. The physical and chemical parameters of the water were checked regularly for getting the data on the influence of these parameters on the rotifer’s population. The highest diversity and density of rotifers recorded during the pre-monsoon season (H= 3.194, D= 0.954) followed by post-monsoon and lowest during monsoon season (H= 2.658, D= 0.898). A total of 40 species of rotifers belonging to 15 genera and 10 families were recorded. Rotifers of Thrissur Kole wetlands are dominated by Brachionidae (12 species)> Lecanidae (11 species)> Trichocercidae (5 species). Keratella cochlearis (29%) and Brachionus falcatus (25%) of the family Brachionidae are the dominant species seen during all seasons. In conclusion, Rotifers represented the important group of zooplankton throughout the current study, about 50% of the collected Rotifers were new to this area and the species richness and abundance of Rotifer shows a significant relationship with the physical and chemical parameters of the water.