The present study investigates the influence of seasonal dynamics on macrobenthic assemblages in four seasons of 2017–2018 from the central sector of Indian Sundarbans which is under the constant threat of climate change. Besides taxonomic analysis, a trait-based approach has also been applied to assess the change in their ecosystem functioning. The maximum species density (11675 ± 11883.31 ind. m⁻²) was observed during the spring season which declines considerably in the monsoon season (5875 ± 6224.08 ind. m⁻²). A total of 95 macrobenthic taxa were recorded from Sundarbans and they were dominated by families like Capitellidae, Donacidae, Magelonidae, Nereididae, Paraonidae and Spionidae. Overall, polychaetes have shown higher taxonomic and functional variation than other groups. Opportunistic polychaete species have shown a prominent compositional shift during post-monsoon seasons. Both the univariate and multivariate analyses have shown a significant relation between macrobenthic composition and environmental parameters. SIMPER has depicted that environmental parameters made the station 4 unique for several types of molluscs like Acteocina estriata, Stenothyra deltae and Meretrix meretrix during spring. Trait percentages also showed a seasonal succession pattern and among the trait categories, burrowers and deposit feeders dominated the estuary. A gradual increase in suspension feeders in spring has been noticed. RLQ approach with fourth-corner analysis was used to unravel the relationship between traits and environmental parameters. Hence, the present study provided a comprehensive idea about the species composition along with their trait categories from such a dynamic habitat. That could be the first stepping stone for a long term monitoring of macrobenthic assemblages from this largest delta on earth.

本研究调查了印度桑达班斯中部地区（受气候变化持续威胁）2017-2018年四个季节中季节动态对大型底栖动物组合的影响。除了分类分析外，还采用了基于特征的方法来评估其生态系统功能的变化。在春季期间观察到最大物种密度（11675±11883.31 ind。m ^-2），而在季风季节则显着下降（5875±6224.08 ind。m ^-2））。总共从桑达班人那里记录了95个大型底栖生物类群，它们主要由科（科），多酸科（Donacidae），麦格龙科（Magelonidae），线虫科（Nireididae），寄生虫科（Parononidae）和天蛾科（Spionidae）控制。总体而言，多语族比其他族群显示出更高的分类学和功能变异。季风后季节，机会性多毛类动物已显示出明显的成分变化。单变量和多变量分析均显示了大型底栖动物的组成与环境参数之间的显着关系。SIMPER描述了环境参数使该站4对于几种类型的软体动物（如Acteocina estriata，Stenothyra deltae和Meretrix meretrix）而言是唯一的在春季。性状百分比也表现出季节性演替模式，在性状类别中，洞穴和沉积物饲养者主导河口。注意到春季春季悬浮喂食器的逐渐增加。采用带有第四角分析的RLQ方法来揭示性状与环境参数之间的关系。因此，本研究为这种动态生境中的物种组成及其特征类别提供了一个全面的思路。这可能是长期监测地球上最大三角洲大型底栖动物组合的第一步。