Spatio-temporal statistical analysis nereididae (polychaeta) abundance in mangrove ecosystems of Northern Kerala, India

Abstract

Nereididae polychaetes are dominant components of estuarine mangrove sediments and respond sensitively to environmental variability. This study assessed the influence of spatial and seasonal changes on nereidid diversity and abundance across an estuarine gradient. Univariate analyses, including the computation of diversity indices (Shannon species diversity index, Margalef ’s species richness index, Pielou’s evenness index valueand Simpson’s species dominance index) were evaluated. Based on these analysis, Station 1 (closer to the sea) consistently exhibited the highest diversity indices values with relatively higher H′ during the pre-monsoon season followed by post-monsoon and lower values during the monsoon. Highest diversity and abundance of polychaete were observed in the 0-10 cm sediment layer compared to the 1020cm layer. Dendronereis aestuarina is the most abundant across all stations, it showed the highest dominance at Station 3 under favourable sediment conditions characterized by higher sand content and reduced organic load, likely due to lower pollution pressure, followed by Neanthes glandicincta.