Fungal Community Dynamics in <i>Cyperus rotundus</i>: Implications for <i>Rhizophora mangle</i> in a Mangrove Ecosystem

Mangrove ecosystems are globally significant for their biodiversity and ecosystem services but face persistent threats from invasive species and anthropogenic disturbances. This study investigates the interactions between <i>Cyperus rotundus</i>, a widespread invasive weed, and fungal communities in the mangrove-adjacent wetlands of Isla Santay, Ecuador. Using metagenomic sequencing of the ITS region, we analyzed fungal diversity in samples from an anthropogenically pressured area and a non-impacted site. Results revealed significant differences in microbial assemblages: the rhizosphere sample from the disturbed area exhibited lower fungal richness and was dominated by <i>Magnaporthaceae</i> (9%) and <i>Aureobasidium melanogenum</i> (5%), both associated with stress-tolerant traits. In contrast, the rhizosphere sample from the non-impacted site showed higher species diversity, with <i>Cladosporium dominicanum</i> (62%) and <i>Talaromyces</i> (11%) as dominant endophytic taxa. Principal Coordinates Analysis (PCoA) and co-occurrence networks highlighted distinct fungal partitioning between the two sample tissues, indicating that <i>C. rotundus</i> mediates microbial composition in response to environmental gradients. These findings underscore the role of microbial communities in the plant’s invasive success and suggest that leveraging beneficial fungi could enhance ecosystem resilience and support wetland restoration. By integrating molecular approaches with ecological insights, this work contributes to a deeper understanding of microbial dynamics in coastal wetlands and informs targeted management strategies to preserve mangrove habitats.