Avian‐Mediated Microalgal Dispersal in Neotropical Wetlands: The Case of the Southern Screamer ( Chauna torquata )

ABSTRACT Dispersal is the process of movement of organisms among habitats across the landscape, and passive dispersal occurs when the transport of organisms or their propagules is mediated by vectors. Research on the role of waterbirds in the dispersal of microalgae through epizoochory and endozoochory remains scarce. We evaluated the ability of a large‐bodied, resident Neotropical waterbird species, the southern screamer ( Chauna torquata ), to disperse microalgae through both epi‐ and endozoochory in Neotropical wetlands. The study was conducted in a Ramsar Site located in the southernmost region of Brazil. Microalgal samples were collected from a natural wetland for reference, from two body regions (toes and feathers) of five adult birds, and from 15 fresh faecal samples of the species. All samples were collected in the same locality and during the cold season. A total of 92 microalgal taxa were recorded in the wetland, while 61 taxa and 154 individuals were found on the toes, 44 taxa and 93 individuals on the feathers, and 18 taxa and 194 individuals in faeces. Microalgal richness differed among the wetland, toes, feathers, and faeces, with the highest richness observed in the wetland. Richness observed on the toes and feathers was higher than that in faeces, whereas richness did not differ between toes and feathers. Pairwise comparisons revealed that the composition of microalgae found in faeces differed significantly from that found in the wetland, toes, and feathers. Our findings demonstrate that southern screamer has a strong potential to disperse microalgae through both epizoochory and endozoochory, although each pathway operates under distinct selective filters. This study highlights the importance of waterbirds in maintaining microalgal connectivity across wetland ecosystems.