Populations change of the Bean Goose (Anser fabalis) wintering at the Upo Wetland, Korea

Abstract

The wintering population of Bean Goose (Anser fabalis) at the Upo Wetland from 2005 to 2010 has been monitored by the long term ecological research (LTER) project in South Korea. The principal objective of this study was to define the primary factors determining the wintering Bean Goose population distribution in the wetland system, such as: usage pattern of habitat in and around the Upo Wetland, and departure timing related to temperature. We conducted a comprehensive literature review regarding Bean Goose population dominance in the wetland, and there was a clear tendency toward an increase in this species' dominance until 2002. The LTER monitoring data also exhibited a similar trend, but not as strongly as was seen in previous research. When the Bean Goose population arrived at the Upo Wetland, they utilized the wetland as their resting site, while they moved to other places surrounding the wetlands to forage for food sources. The flight distance of the Bean Goose for feeding ranged between ca 1 to 25 km from the Upo area. The population changes of the Bean Goose at the Upo were related to the lowest temperatures in winter (r = -0.461, P = 0.009). In particular, the lowest temperature in March was important for creating flocks of the Bean Goose before returning to the northern region. The results of this study can provide us with basic information regarding migratory bird population changes in the Upo Wetland in relation to the land use patterns of human beings, as well as meteorological variations.