Multiple Spatial Scale Analysis Provide an Understanding of Benthic Macro-Invertebrate Community Structure Across a Lagoonal Ecosystem

Chilika, the largest coastal lagoon of Asia, represents a complex transitional zone between terrestrial and marine ecosystems. In this study benthic macro-invertebrate community structure was elucidated based on multiple spatial scales approach (station-wise, sector-wise and region-wise) across Chilika from June 2013 to February 2015 (temporal scale), encompassing 23 pre-selected stations in link with measurement of abiotic parameters. Sixty two macro-invertebrate species representing seven macrofaunal groups were encountered, of which gastropods were the most abundant in terms of density (~96%) and species composition (~43%), and crustaceans were the least. The structure of the macrofaunal community (in terms of abundance) showed significant differences across spatial (station-wise, sector-wise and region-wise), and temporal scales (month-wise). While macro-invertebrate species composition revealed heterogeneity both station-wise and month-wise but it was found to be homogenous within the sector-wise and region-wise scales. BIO-ENV analysis indicated that salinity together with sediment nature were major abiotic variables associated with observed macro-invertebrate patterns. The results together demonstrated that macro-invertebrate communities are adapted to prevailing environmental conditions of Chilika lagoon; homogeneous and heterogeneous distribution and diversity patterns across multiple spatial scales revealed assemblages distinct to this ecosystem. The multiple scales approach could prove to be useful for ecological monitoring of lagoons.