Abstract

Mangrove sediments represent dynamic coastal microbiomes that harbor diverse microbial communities under fluctuating environmental conditions. Unlike extensively studied bacterial communities, yeast microbiomes in mangrove habitats remain poorly understood. This study evaluated the diversity, community dynamics, environmental associations, and ecological interaction networks of yeast assemblages in mangrove sediments from Central Java, Indonesia, using ITS metabarcoding and multivariate ecological analyses. Environmental DNA extracted from sediment samples was sequenced using the Illumina NovaSeq 6000 platform, followed by ASV delineation, taxonomic curation, diversity analyses, ordination, variation partitioning, and co-occurrence network inference. Malassezia-associated taxa dominated mangrove sediment yeast communities, with pronounced geographic variation in subordinate taxa among ecosystems. Alpha- and beta-diversity analyses revealed heterogeneous community patterns and compositional tendencies across mangrove sediments. Salinity, total dissolved solids, Pb, and Cu were evaluated as potential environmental gradients; however, permutation tests indicated that the measured variables did not significantly explain yeast community composition. Co-occurrence network analysis revealed predominantly positive and modular associations, with several highly connected taxa potentially contributing to network connectivity and ecological organization. These findings expand current understanding of fungal microbiome organization in tropical mangrove ecosystems while emphasizing the need for cautious interpretation of environmental drivers in DNA-based sediment metabarcoding studies.

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