To find out a clear picture of species diversity and distribution,various univariate and multivariate analyses have been carried out andresults are discussed. Individual species is a simple and useful measureof the biological system. The species individual diversity in the presentstudy registered a wide fluctuation between 4.311 (monsoon) and 5.167(summer) among stations and seasons. The lower species diversity wasrecorded during monsoon and higher diversity values during summerin the study area. This is in conformity with the earlier observationsmade in Vellar [51] and Coleroon estuaries [31]. Moreover, PearsonTH and Rosenberg R [52] proposed that the use of diversity indicesis advantageous for the description of fauna at different stages insuccession. In the present study, negative correlation is obtainedbetween species richness and diversity at stations I (r=-0.999), II (r=-0.997) and III (r=-0.999) at p<0.05 level.All the nutrients (TN, TP and TOC) are found enriched in thesediment during monsoon. These nutrients might have reached thebenthic realm through food web during summer and pre-monsoonseasons. The species richness of benthic macrofauna was foundmaximum during the summer season (32.70). A similar observationwas reported by Kumar RS [37] in Cochin backwaters. The lowrichness was recorded during monsoon (16.69) might be due to thehigh freshwater inflow with low saline conditions, which in turn affectthe distribution of benthos, particularly the polychaetes. Maximum
diversity and richness recorded during summer at the all sites might be
due to stable and optimum environmental factor such as salinity, which
plays an important role in faunal distribution and abundance. Shannon
diversity was exceptionally high and it was in the range of 4.311-5.167.
The minimum (4.311) and maximum (5.167) was recorded at station IIduring the monsoon season and at station I during the summer season,
respectively. Shannon diversity in the present study was considered to
be good and the range recorded in the present study vouchsafes for
the healthy nature of mangrove ecosystem. Similar seasonal pattern is
evident from the view of Kundu et al.
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