Abstract

Mangrove ecosystems are ecologically important coastal habitats, yet the organization of fungal communities in mangrove sediments remains insufficiently understood. This study investigated the taxonomic composition, community structure, and functional guild distribution of fungal communities in mangrove sediments from five sites in Central Java, Indonesia, using ITS1-based environmental DNA metabarcoding. Sediment samples were analyzed through alpha and beta diversity metrics, taxonomic profiling, shared-versus-unique taxa assessment, and FUNGuild-based functional annotation. Alpha and beta diversity showed no significant differences among sites, indicating weak broad-scale spatial structuring. In contrast, taxonomic profiling revealed pronounced heterogeneity at finer taxonomic levels, with communities dominated by Ascomycota and Basidiomycota and composed of both a conserved core microbiome and numerous site-specific taxa. Genera such as Malassezia, Aspergillus, and Cladosporium were consistently detected across sites. Functional guild analysis showed that fungal communities were dominated by pathotrophic and undefined guilds, whereas saprotrophic fungi formed a secondary but ecologically important component and symbiotrophs remained minor. Overall, these findings indicate that mangrove sediment fungal communities are taxonomically dynamic but functionally more conserved across sites, supporting partial taxonomic–functional decoupling and suggesting a role for functional redundancy in maintaining ecosystem stability.

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