Conclusion
The present study showed that algal growth rate, biomass production, and elemental contents varied depending on the leaf litter leachates from different tree species, due not only to differences in N and P concentrations but also to those of micronutrients. These results suggest that the stoichiometry and composition of leaf litter leachate can cause substantial changes not only in algal fitness and primary production, but also in mass transfer from algae to herbivores. Although we conducted this study using only a single algal species, the responses to the changes in leaf litter leachate may differ between algal species and other heterotrophic organisms that utilize organic matter in leaf litter leachate. This possibility is worth investigating in future studies, as the effects of the change and succession in the surrounding vegetation may have extended to the composition of the entire community in the freshwater ecosystems. In this study, we investigated the short-term and direct effects of leaf litter using leaf litter leachate for 7 days of incubation. In nature, the effects of leaf litter on aquatic ecosystems may last longer through decomposition in soils and sediments. Therefore, to fully understand the effects of vegetation changes on the aquatic community, long-term monitoring studies are needed in aquatic ecosystems where the catchment vegetation has been changed.