Invasive Acacia Tree Species Affect Instream Litter Decomposition Through Changes in Water Nitrogen Concentration and Litter Characteristics

Non-native nitrogen-fixing Acacia species have been invading riparian ecosystems worldwide, potentially threatening stream communities that strongly depend on allochthonous litter. We examined the effects of invasion native deciduous temperate forests by litter decomposition and associated fungal decomposers in streams. Litter (Alnus glutinosa Quercus robur) invasive (Acacia melanoxylon) were enclosed fine-mesh bags immersed three invaded streams, for 14–98 days. rates, biomass, aquatic hyphomycete sporulation rates higher than likely due to water nitrogen concentration found Alnus had richness, probably because they soft rich. robur also high but lower Al. glutinosa, polyphenol carbon:nitrogen ratio. melanoxylon most it was very tough. Thus, varied order: > Q. Ac. melanoxylon. The community structure differed between among species, suggesting microbes sensitive characteristics. Overall, increases alterations characteristics promoted may affect activity microbial decomposers, instream decomposition, thus altering functioning ecosystems.