Responses of Benthic Macroinvertebrates to Long‐Term Environmental Variability in Two Key Habitats Along the West Coast of India

ABSTRACT

Benthic macroinvertebrates form the foundation of coastal wetland food webs and play a critical role in sustaining higher trophic levels, including wintering migrant shorebirds. However, long‐term changes in major benthic prey groups and their environmental drivers remain poorly quantified in tropical coastal systems. In this study, we analysed a 14‐year dataset (2010–2023) from two key adjacent microhabitats along the west coast of India to assess long‐term trends in benthic macroinvertebrate abundance and to identify the key physicochemical factors regulating benthic dynamics. Benthic macroinvertebrates were sampled systematically alongside water‐quality parameters and sediment properties, and benthic macroinvertebrate abundance was modelled using a negative binomial framework to account for overdispersed count data. Results reveal a persistent long‐term decline in overall benthic prey abundance. Water chemistry and sediment properties emerged as important drivers, with increasing chlorophyll a, pH, salinity and water phosphate exerting strong negative effects on prey abundance. Negative relationships between sediment textural variables and prey abundance also suggest a possible influence of sediment composition on benthic prey groups. Taxon‐specific responses showed differences in sensitivity to environmental variation, with polychaetes and bivalves showing pronounced sensitivity to environmental stress, while some crustaceans exhibited greater tolerance to altered conditions. These findings demonstrate that interacting physicochemical stressors are influencing the abundance of major benthic prey groups over decadal timescales, with important implications for coastal food webs and the trophic support of winter migrant shorebirds. The study underscores the value of long‐term monitoring and process‐based modelling for changes in benthic prey abundance and informing effective coastal wetland management.