The invasive aquatic fern Azolla filiculoides negatively impacts water quality, aquatic vegetation and amphibian larvae in Mediterranean environments

Quantifying the ecological impacts of alien aquatic macrophytes: A global meta‐analysis of effects on fish, macroinvertebrate and macrophyte assemblages

“…In addition, the fibrous litter produced by many invasive emergent taxa indirectly displaces native macrophytes through nutrient enrichment and light reduction (Farrer & Goldberg, 2009; Holdredge & Bertness, 2011; Larkin et al, 2012; Vaccaro et al, 2009). Floating and submerged invasive macrophytes may also displace native vegetation (Boylen et al, 1999; Houston & Duivenvoorden, 2002; Pinero‐Rodríguez et al, 2021; Silveira et al, 2018), probably via superior resource acquisition (Madsen, 1998) and/or phenotypic plasticity (Fleming & Dibble, 2015; Riis et al, 2012). Displacement of native macrophytes by aliens may also be promoted by the production of plant secondary metabolites which defend the invader from herbivores (Erhard et al, 2007; Grutters et al, 2017) or inhibit the growth of native macrophyte competitors (Dandelot et al, 2008; Thiébaut et al, 2018).…”

Ecosystem services provided by freshwater macrophytes

“…Invasive macrophytes may also impact negatively diversity of native invertebrates (Coetzee et al, 2014), native fish (Carniatto et al, 2013;Velle et al, 2021) and threaten rare animal species (e.g., birds; Reinert et al, 2007). Economic damage, including negative impacts for fishing, navigation, swimming, tourism and a variety of other water uses, have also been recorded as a result of excessive macrophyte growth (Pieterse & Murphy, 1990;Verhofstad & Bakker, 2019). Macrophytes can even complicate the restoration of lakes (Sarvala et al, 2020).…”

“…For example, non-native invasive species usually become a nuisance (Hussner et al, 2021). Eutrophication increases the growth of freefloating macrophytes (Thomaz et al, 2006) including non-native species (Villamagna & Murphy, 2010;Coetzee & Hill, 2012), while dams provide habitat for submerged macrophytes (Thomaz et al, 2009;Pitelli et al, 2014) that can grow excessively and negatively affect multiple uses of water bodies (Pieterse & Murphy, 1990;Marcondes et al, 2003). There is also evidence that disease transmission is enhanced by alien invasive macrophytes (Stone et al, 2018), suggesting that even the decrease in the service of disease vector regulation may be related to human interference (i.e., species introductions).…”

“…The macrophyte community (hereafter ''macrophytes'') is considered a key element in freshwater ecosystems, especially in shallow ones (Scheffer, 2004;Jeppesen et al, 2007a, b). These plants change the physical and chemical environment (Bini et al, 2010;Pinero-Rodriguez et al, 2020), participate intensively in nutrient cycling (Carignan & Kalff, 1980;Wetzel, 2001;Wahl et al, 2021), produce biomass which is used by herbivores and detritivorous (Martinez et al, 2013;Peel et al, 2019;Franceschini et al, 2020) and provide habitat for other communities (Dibble et al, 2006;Dibble & Thomaz, 2009;Gething et al, 2020;Deosti et al, 2021), with consequences for higher trophic levels (Gomes et al, 2012;dos Santos et al, 2020;Paz Cardozo et al, 2021;Yofukuji et al, 2021).…”

Hydrocharis laevigata in Europe

“…There is a common consensus, supported by the Red List of European Habitats [ 6 ], that the key threats to European aquatic and wetland habitats are alterations to hydrological systems, climate change, pollution, and invasive species [ 7 ]. In Europe, native freshwater biota are facing increasing competitive pressure due to the arrival and spread of floating-leaf aquatic plants (e.g., Azolla filiculoides and Eichhornia crassipes ) in inland water bodies [ 8 , 9 , 10 , 11 , 12 , 13 , 14 , 15 ]. Of particular concern is the recent appearance of an aggressive invasive alien species (AIS), Hydrocharis laevigata , whose common names include South American spongeplant, smooth frogbit, or Amazon frogbit.…”