Map of distribution of the four most representative fish species in the 2000s and 2010s, respectively. The dots represent where the species has been recorded in the corresponding oxbow lakes. Carassius langsdorfii: native species with the most significant SCBD increase; Lefua nikkonis: native species with the most significant SCBD decrease; Misgurnus anguillcaudatus: non-native species with the most significant SCBD increase; Pseudorasbora parva: non-native species with the most significant SCBD decrease.