“…The disruption of urban stream networks, together with the lack of headwaters, can therefore modify the riparian community structure along the entire stream network due to the lack of upstream source populations and decreased potential for hydrochory (dispersal by water), both of which have been shown to drive downstream riparian plant community composition and diversity patterns in forested landscapes (Kuglerová, Jansson, Sponseller, Laudon, & Malm-Renöfält, 2015;Nilsson et al, 1994). These effects are exacerbated by forest fragmentation and overland dispersal from species pools situated in urban parks, gardens, and other human-made habitats, which can contribute novel non-native species (Maskell, Bullock, Smart, Thompson, & Hulme, 2006;Moffatt, McLachlan, & Kenkel, 2004;Rouquette et al, 2013;Schwoertzig, Poulin, Hardion, & Trémolières, 2016). Finally, soils in urban riparian areas are exposed to extensive loads of sediment as well as organic and inorganic pollutants and contaminants (Kaushal & Belt, 2012;Wenger et al, 2009).…”