Response of herbivorous geese to wintering habitat changes: conservation insights from long-term population monitoring in the East Dongting Lake, China

Abstract

The majority of Eastern China’s herbivorous geese overwinter in the East Dongting Lake, China, and there is growing concern about how changes in their habitats can affect the goose populations. General linear regressions were used to analyze the relationship between changes in the abundances of three herbivorous geese (Eastern Tundra Bean Goose Anser fabalis serrirostris, Lesser White-fronted Geese Anser erythropus, and Greater White-fronted Goose Anser albifrons frontalis) and their wintering habitats in the East Dongting Lake during 2002/2003–2014/2015. The fluctuations in three herbivorous goose abundances exhibited negative correlations with changes in interval duration (i.e., days between complete sedge meadow exposure and goose arrival in the study areas), but positive correlations with the normalized difference vegetation index (NDVI) of sedge meadow in late wintering seasons. Comparing to Eastern Tundra Bean Goose, Lesser White-fronted Geese and Greater White-fronted Geese were more sensitive to habitat changes. No significant correlations were observed between goose abundances and both mean water levels and sedge meadow areas. Results indicate that the variations in herbivorous goose abundances may be caused by changes in the NDVI of sedge meadows and the interval durations between sedge meadow exposure and goose arrival. The earlier flood recession can accelerate the exposure, growth, and withering of sedge meadows (low NDVI in late January), thereby creating unsuitable feeding conditions for the geese in the wintering seasons. These findings are important as efforts are made to protect these valuable species from the effects of human intervention, and in particular, the Three Gorges Dam project.