Changes in the functional feeding groups of macrobenthic fauna during mangrove forest succession in Zhanjiang, China

Understanding the relationships between mangrove forest succession and the functional diversity of mangrove fauna could facilitate the restoration of mangrove ecosystems, which have been severely damaged in recent decades. The current report describes changes in macrobenthic functional diversity in a mangrove chronosequence that included a primary community (unvegetated shoal), an early community (Avicennia marina), a middle community (Aegiceras corniculatum), and a late community (Bruguiera gymnorrhiza+Rhizophora stylosa) in Zhanjiang, China. Phytophages were the dominant macrobenthic functional feeding group regardless of mangrove succession stage, sampling season, or macrobenthic faunal parameter (species richness, abundance, and biomass). As mangrove succession progressed, the proportions of macrobenthic species richness, abundance, or biomass represented by omnivores significantly increased (except for biomass and in the late stage; ranged from 0.065 to 0.230 and 0.033 to 0.368, respectively in wet season, and 0.000 to 0.192 and 0.000 to 0.396, respectively in dry season), while the proportions significantly decreased for detritivores during the dry season (ranged from 0.156 to 0.056, 0.107 to 0.019, and 0.066 to 0.005, respectively). Non-metric multi-dimensional scaling and PERMANOVA also indicated that the structure of macrobenthic faunal functional feeding groups was significantly affected by mangrove succession. Further analyses indicated that the changes in the relative dominance among macrobenthic faunal functional feeding groups during mangrove succession were mainly associated with changes in plant density, coverage/canopy density, and total nitrogen content of sediment, i.e., they were mostly associated with changes in food sources. The results increase our understanding of the relationship between benthic functional diversity and mangrove succession and could help guide mangrove restoration in China and around the world.