Assessing Changes of Habitat Quality for Shorebirds in Stopover Sites: a Case Study in Yellow River Delta, China

The population of shorebirds in the East Asian-Australasian Flyway (EAAF) has severely declined over the past several decades. One reason for this condition is low survival in stopover sites in the Yellow Sea Ecoregion (YSE) due to habitat degradation. Here, we focused on shorebird habitat quality in the Yellow River Delta (YRD), which is a representative shorebird stopover site in the YSE on the EAAF. We used the InVEST model to assess the past and future shorebird habitat quality changes by considering the effects of anthropogenic threats. The entire duration of the study was 1999-2016, and the modeling was done on 2000 and 2015 data. Our results indicate that the abundance of 11 shorebird species had significant downward trends (70-97% reduction) during 1999-2015. Tidal flats in the nature reserve had higher habitat quality than that in the northwestern (NW) and eastern (E) parts of the YRD because major mariculture occurred in NW and E. The mean habitat qualities in NW and E decreased by 27 and 31% during 2000-2015, respectively. The optimal habitat in the YRD declined from 1433km(2) in 2000 to 1154km(2) in 2015. The habitat quality decreased significantly in E and Dongying Port parts during 2015-2020.