“…The global abundance of these systems remains uncertain (Verpoorter et al, 2014), but statistical extrapolation suggest there may be around 16 million artificial reservoirs worldwide (Lehner et al, 2011). Regional-scale inventories indicate that collectively upwards of 8 million farm reservoirs exist in the USA (Brunson, 1999;Smith et al, 2002), China (Chen et al, 2019), India (Anbumozhi et al, 2001), South Africa (Mantel et al, 2017), and Australia alone (Lowe et al, 2005;MDBA, 2008;Grinham et al, 2018a). The density of farm reservoirs can exceed 30 % of agricultural area in some regions such as China where food demand is high (Chen et al, 2019).…”