Effect of invasive Hovenia dulcis on microbial decomposition and diversity of hyphomycetes in Atlantic forest streams Cristiane Biasi a, * , Lucas Eug ^ enio Fontana a, b , Rozane Maria Restello a , Luiz Ubiratan Hepp a a Programa de P os-Graduaç~ ao em Ecologia, Departamento de Ci^ encias Biol ogicas, Universidade Regional Integrada do Alto Uruguai e das Miss~ oes, Avenida Sete de Setembro,1621, CEP 99709-910, Erechim, Rio Grande do Sul, Brazil b Programa de P os-Graduaç~ ao em Ecologia, Departamento de Ecologia e Zoologia, Universidade Federal de Santa Catarina, Campus Universit ario, s/n, CEP 88040-900, Florian opolis, Santa Catarina, Brazil article info Article history: Received 10 June 2019 Received in revised form 5 November 2019 Accepted 8 November 2019 Available online xxx Corresponding Editor: Felix B€ arlocher Keywords: Aquatic hyphomycetes Fungal reproduction Beta diversity Alpha diversity Riparian zones Leaf breakdown 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. © 2019 Elsevier Ltd and British Mycological Society. All rights reserved. 1. Introduction The introduction of invasive non-native species in riparian zones is a topic of concern for freshwater ecology (Laitung and Chauvet, 2005; Ferreira et al., 2015, 2018; Gomes et al., 2016; Figueiredo et al., 2018). The pronounced dependence of streams on organic allochthonous material from riparian vegetation is closely related to the ecological processes in forests and streams, and both are affected by forest management (Laitung and Chauvet, 2005; Ferreira et al., 2012; Casotti et al., 2015). Invasive plant species may decrease the diversity of the native forest, becoming regionally dominant and promoting the displacement of intolerant species (Castro-Díez and Alonso, 2017). This effect may be potentiated if the invasive species has allelopathic compounds (Medina-Villar et al., 2017). The invasive plant can cause homogenization of stream allochthonous material and accelerate the substitution of native trees by non-native species with dissimilar traits (e.g. timing of leaf senescence) (Chauvet et al., 2016; Ferreira et al., 2016). Thus, al- terations in riparian composition have the potential to change the abundance, quality and seasonality of litter inputs (Hughes and Fahey, 1994; Ferreira et al., 2016) and thereby affect stream food webs (Ferreira et al., 2012; Figueiredo et al., 2018). Hovenia dulcis is a plant species native to Asia (Kopachon et al., 1996), and is considered invasive in forests of South America and Tanzania (Hyun et al., 2010; Padilha et al., 2015). This species is a fast-growing tree and aggressively proliferates in degraded areas and in native forests. This species is usually cultivated for wood or as a windbreak (Carvalho, 1994). Known as the Japanese raisin tree, H. dulcis has been cultivated in regions of Cfa, Cfb and Cwa sub- tropical climate types, following the K€ oppen classification (Alvares et al., 2013), and it is one of the most aggressive invasive species in subtropical forest (Zenni and Ziller, 2011). The leaves and pseudo- fruits have allelopathic activity (Wandscheer et al., 2011; Ribeiro et al., 2019), and their seeds are widely dispersed by mammals and birds (Schumacher et al., 2008; De Lima et al., 2015). In streams, * Corresponding author. E-mail addresses: cristiane.biasi@gmail.com, cristianebiasi@hotmail.com (C. Biasi). Contents lists available at ScienceDirect Fungal Ecology journal homepage: www.elsevier.com/locate/funeco https://doi.org/10.1016/j.funeco.2019.100890 1754-5048/© 2019 Elsevier Ltd and British Mycological Society. All rights reserved. Fungal Ecology 44 (2020) 100890