Functional Diversity of Neotropical Aquatic Hyphomycetes: Insights Into Environmental Drivers

ABSTRACT Aquatic hyphomycetes species traits are critical for organic matter processing in low‐order streams. This study evaluated the functional diversity of hyphomycetes associated with Nectandra angustifolia leaves in tropical and subtropical streams, presenting data on sporulation rates, species abundance, and decomposition rates. We examined Functional Richness (FRic), Divergence (FDiv), Dispersion (FDis), and Evenness (FEve) in aquatic hyphomycete assemblages, relating these to environmental variables such as temperature, pH, dissolved oxygen, and electrical conductivity. In tropical streams, poor leaf quality promoted wood saprotroph and foliar endophyte dominance. Moreover, our findings indicated increased functional diversity (FRic and FDis) in subtropical streams compared to tropical streams, reflecting larger conidiophores, diverse conidia shapes, and the prevalence of litter saprotrophs. We also linked colder waters to an increase in trait diversification. Additionally, environmental fluctuations, such as cooler temperature, more dissolved oxygen, and neutral pH, increased FRic, which reflects greater dissimilarity among co‐occurring taxa. Our results underscore the significant role of water properties in shaping aquatic hyphomycete assemblage functional diversity.