Abstract: To investigate the characteristics of macrobenthic feeding functional groups and their relationship with environmental factors in the Spartina alterniflora wetland of southern Zhejiang, a comprehensive survey was conducted in July and August 2020 in four sites with extensive S. alterniflora cover: Sanmen Bay, Yueqing Bay, Oujiang Estuary, and Feiyun River Estuary. The survey examined wetland vegetation, macrobenthos, water quality, and sediment characteristics. A total 59 species of macrobenthos were identified, classified into five feeding functional groups: carnivore (CA), detritivore (DE), omnivore (OM), herbivore (HE), and planktivore (PL), comprising 20, 13, 11, 8, and 7 species, respectively. Among these feeding groups, DE and PL were dominated, collectively accounting for 70% of relative abundance, followed by CA and HE, with a total relative abundance of 26%. OM was the least abundant, accounting for only 4%. Notably, only three feeding functional groups were present in the Feiyun River Estuary, whereas all five groups were recorded in the other three sites. Cluster analysis revealed significant differences between the Feiyun River Estuary and the other three regions. Redundancy analysis showed that environmental factors such as S. alterniflora height, interstitial water, and sediment properties played crucial roles in shaping the distribution of feeding functional groups. Among all these factors, total salt content of sediment was the most important one. S. alterniflora facilitated the expansion and survival of Phascolosoma arcuatum, highlighting its ecological influence on microbenthic communities.

Key words: southern Zhejiang, Spartina alterniflora wetland, macrobenthos, feeding functional group, environmental factor