Effect of invasive Hovenia dulcis on microbial decomposition and diversity of hyphomycetes in Atlantic forest streams

Abstract

The replacement of native vegetation in riparian areas by invasive species may cause homogenization, and change the quality of allochthonous material entering streams. It may also affect colonization by aquatic hyphomycetes, which are essential for leaf decomposition. We tested the effects of non-native Hovenia dulcis on aquatic hyphomycete communities in a field experiment, as well as the litter decomposition mediated by microbial decomposers. Our findings showed that: (i) the Hovenia leaves had a faster decomposition rate than a mixture of leaves from native species; (ii) fungal sporulation rates were lower on the invasive species; (iii) Hovenia reduced the beta diversity of aquatic hyphomycetes; (iv) Hovenia made a greater contribution to alpha diversity (across litter bags) than the native mix (i.e. higher species richness), but the contribution of the native mix to the community beta diversity (across streams) was high. Our results illustrated that the composition of the riparian forest had important effects on hyphomycete communities.