Figure 2. Population abundance indices of five Anatidae species from 2001 to 2012 in the 25 wetlands differing in protection status in the Yangtze floodplain using Generalized Additive Mixed Models (GAMM). Blue line: wetlands designated as national nature reserves; red line: provincial nature reserves; yellow line: county nature reserves.

The solid line shows the population abundance index of each species and the broken lines show the 95% confidence intervals (barely visible, due to small confidence intervals). (a) bean goose; (b) greater white-fronted goose; (c) lesser white-fronted goose; (d) swan goose; (e) tundra swan. As lesser white-fronted goose was only counted in the national nature reserves, there are no population trends shown in provincial and county nature reserves for this species.