Search

Continuing declines in abundance of many waterbird species on wetland ecosystems require explanations to support effective management interventions. We used 6 year survey data from Shengjin Lake National Nature Reserve in the Yangtze River Floodplain, China, to study the effects of ecological and anthropogenic variables as determinants of waterbird species abundance. Our results showed that effects were guild-dependent, although distance to nearest human settlements had the largest adverse effects on bird abundance across all guilds. These results suggested that although the abundance of waterbird species could be affected by habitat conditions and buffalo grazing activities, Yangtze River Wetlands would most likely benefit most from reduced pressure from the proximity to the surrounding human population. We suggest that screening and/or restricting public access at some key sites may be the most cost-efficient way to restrict or reduce human activity in these wetlands, to improve the conservation status and wintering conditions for these waterbirds. [ABSTRACT FROM AUTHOR]

The seasonally flooded Yangtze Valley Floodplain wetlands of China are globally important for wintering waterbirds in the East Asian-Australasian Flyway. These birds have declined in the last 60 years, so understanding factors shaping waterbird distribution and abundance patterns is critical for their conservation. We applied linear mixed models to investigate the effects of climate, winter water area and inundation area (the difference between maximum flooded and winter dry season water area) on waterbird abundance and diversity at 72 lakes in 2005 and 2016. Neither winter water area nor climate featured in the best models, rather inundation area was the key determinant of waterbird abundance and diversity. Future water abstraction and land claim will therefore have greater impacts on waterbird abundance and diversity than likely climate change effects. Significant declines in waterbird abundance and diversity between 2005 and 2016 were not explained by modelled variables and there was no reduction in wetland inundation areas to explain these declines, confirming other factors were responsible. These potentially include declining wetland quality affecting carrying capacity ( e . g . flooding phenology, disturbance, habitat loss and degradation, declining water quality caused by eutrophication and pollution) and/or factors limiting migratory waterbird populations at other stages in their life cycle elsewhere. The studied Yangtze lakes are amongst the best for wintering waterbirds and many are protected for their biodiversity, suggesting such protection cannot fully safeguard these internationally shared populations when threatened by other, currently unknown factors. This confirms the urgent need for more research to safeguard these ephemeral lake systems for their global biodiversity significance. [ABSTRACT FROM AUTHOR]

Summary While wild goose populations wintering in North America and Europe are mostly flourishing by exploiting farmland, those in China (which seem confined to natural wetlands) are generally declining. Telemetry devices were attached to 67 wintering wild geese of five different species at three important wetlands in the Yangtze River Floodplain (YRF), China to determine habitat use. 50 individuals of three declining species were almost entirely diurnally confined to natural wetlands; 17 individuals from two species showing stable trends used wetlands 83% and 90% of the time, otherwise resorting to farmland. These results confirm earlier studies linking declines among Chinese wintering geese to natural habitat loss and degradation affecting food supply. These results also contribute to explaining the poor conservation status of Chinese wintering geese compared to the same and other goose species wintering in adjacent Korea and Japan, western Europe and North America, which feed almost entirely on agricultural land, liberating them from winter population limitation. [ABSTRACT FROM AUTHOR]