Description:
<jats:title>Abstract</jats:title><jats:p><jats:list><jats:list-item><jats:p><jats:italic>Eucalyptus</jats:italic>is one of the most cultivated genera globally. Conversion of native forests into<jats:italic>Eucalyptus</jats:italic>spp. monocultures leads to species‐specific changes in the quality of the litter that contributes to the structure and function of allochthonous‐based aquatic systems.</jats:p></jats:list-item><jats:list-item><jats:p>We used a microcosm approach to compare the relative importance of structural and chemical leaf trait variability among congeneric exotic<jats:italic>Eucalyptus</jats:italic>species (<jats:italic>E. camaldulensis</jats:italic>,<jats:italic>E. globulus</jats:italic>,<jats:italic>E. grandis</jats:italic>, and<jats:italic>E. nitens</jats:italic>) and two Portuguese native species—alder (<jats:italic>Alnus glutinosa</jats:italic>) and oak (<jats:italic>Quercus robur</jats:italic>)—on microbial‐mediated decomposition and invertebrate shredder (Trichoptera:<jats:italic>Sericostoma vittatum</jats:italic>) consumption.</jats:p></jats:list-item><jats:list-item><jats:p>Structural leaf traits, rather than chemical characteristics, appeared to be the main determinants of leaf‐processing dynamics. Differences between the exotic species were mainly determined by the persistence (<jats:italic>E. globulus</jats:italic>,<jats:italic>E. grandis</jats:italic>, and<jats:italic>E. nitens</jats:italic>) or detachment (<jats:italic>E. camaldulensis</jats:italic>) of the cuticular barrier soon after immersion. Detachment favoured an earlier and higher level of fungal colonisation, as well as a higher mass loss.</jats:p></jats:list-item><jats:list-item><jats:p><jats:italic>Sericostoma vittatum</jats:italic>exhibited higher consumption rates when fed by the nitrogen‐rich and softer alder leaves,<jats:italic>E. camaldulensis</jats:italic>, and oak. Consistently lower consumption rates were observed in the other three<jats:italic>Eucalyptus</jats:italic>species (64–77% lower than<jats:italic>E. camaldulensis</jats:italic>). Leaf litter from these species was colonised by a lower number of fungal species and was dominated by<jats:italic>Flagellospora curta</jats:italic>.</jats:p></jats:list-item><jats:list-item><jats:p>Results suggest that streams adjacent to<jats:italic>E. camaldulensis</jats:italic>monocultures receive a continuous supply of easily degradable organic matter throughout the year. The potential effect of subsidies from this species in alleviating the general negative impacts of<jats:italic>Eucalyptus</jats:italic>plantations on native bordered aquatic systems remains to be evaluated.</jats:p></jats:list-item></jats:list></jats:p>