Microalgae on anuran skin: evidence of potential epizoochorous transport in coastal wetlands

Abstract Freshwater microalgae are key components of aquatic ecosystems, but their dispersal mechanisms remain poorly understood. Animal-mediated dispersal of microalgae has been documented for birds, mammals, and invertebrates, yet the role of amphibians in microalgal transport under natural conditions remains largely unknown. We conducted a field survey in coastal wetlands of the southern Brazilian Coastal Plain to investigate potential epizoochorous transport by eight anuran species across grassland and dune habitats. A total of 320 individuals were sampled, and microalgae adhered to 12.81% of frogs. Eleven taxa from three classes (Zygnematophyceae, Chlorophyceae, and Ulvophyceae) were recorded, with filamentous Ulothrix and Oedogonium being the most frequent and abundant. Microalgal richness and abundance per frog skin did not differ between habitats, but community composition differed significantly: assemblages on grassland frogs were more heterogeneous, whereas those on dune frogs were more homogeneous and dominated by filamentous taxa. All microalgae recorded were freshwater species, suggesting that contact with aquatic environments drives potential transport. These results provide field-based evidence that amphibians can act as potential vectors of freshwater microalgae, and indicate that even low-frequency transport events may contribute to the local redistribution of viable algal cells and the connectivity of microalgal communities across wetland mosaics.