“…Wetlands are receiving increasing attention due to the multiple ecosystem services they provide (MEA, 2005; Maltby and Acreman, 2011), especially in urban areas where they act as critical green infrastructures for flood control, water purification, aesthetics, cooling effect and recreation (Taha, 1997; Bolund and Hunhammar, 1999; Lee and Scholz, 2006; Sun et al, 2012; McLaughlin and Cohen, 2013). Empirical evidence shows that wetland ecosystem services related to water quality are generally improved by higher plant diversity, including increased nitrogen removal as well as reduced phosphorus loss and methane efflux (Engelhardt and Ritchie, 2001; Bouchard et al, 2007; Brisson et al, 2020). Yet, wetlands are generally highly vulnerable to invasion by exotics (Zedler and Kercher, 2004; Loiselle et al, 2020; Price et al, 2020) and wetland plants are more widely distributed than upland ones (Santamaría, 2002; Ricklefs et al, 2008), which suggests that these ecosystems are prone to biotic homogenization.…”