Abstract
Migratory waterbird communities are quick to respond to ecosystem degradation, and they are widely considered to be important bioindicators of complex environmental changes. The swan goose (Anser cygnoides) has been listed as a globally vulnerable species in the International Union for Conservation of Nature (IUCN) Red List of Threatened Species. This species currently winters almost exclusively in China and is mostly concentrated on lakes in the middle and lower catchment of the Yangtze River floodplain, especially in Poyang Lake, Jiangxi province and some sites in Anhui province. In the past few years, the population of A. cygnoides has fluctuated. To protect this fragile Anatidae species, long-term and accurate population estimation is both necessary and urgent. In this study, we evaluated the change in numbers and distribution of A. cygnoides by comparing surveys conducted in 2004 and 2005 with more recent ones conducted in 2015 and 2016. A reduction in the count number of this species occurred in the survey sites. After a statistical Mann-Whitney U test, the count numbers of A. cygnoides decreased significantly at the survey sites in Anhui province and the abundance decrease at the survey sites in Poyang Lake was only marginally significant. The inaccessibility of the new sites revealed by satellite tracking impeded a more prudent and comprehensive estimate of the population change. Satellite tracking technology may be a tool to consider for increasing the efficiency of data acquisition. Information transmitted from satellite tracking devices can help us to better understand the species’ behavior and wintering habitat. This technology has the potential to substitute costly and time-consuming field surveys. Conservation designs and management plans must be created for specific national nature reserves and key wintering sites. A more efficient long-term species monitoring system with improved spatial coverage should be conducted to safeguard wintering A. cygnoides.
Highlights
Migratory waterbird communities are quick to respond to ecosystem degradation and they are widely considered to be important bioindicators of complex environmental changes [1,2,3]
Anhui and Jiangxi provinces had the highest number of A. cygnoides; namely, 95% of total A. cygnoides number
The vast majority of the birds was concentrated in Jiangxi province, especially in the area of Poyang Lake
Summary
Migratory waterbird communities are quick to respond to ecosystem degradation and they are widely considered to be important bioindicators of complex environmental changes [1,2,3]. Compared to other Anatidae species, such as the greater white-fronted goose (Anser albifrons) and the bean goose (Anser fabalis), the A. cygnoides population has decreased steeply [15,16] The reasons behind this population decrease include wetland degradation, food source shortages and hydraulic changes in wintering areas [14,17]. The count data derived from field surveys were the primary data source for species population estimation and distribution confirmation Such surveys were typically costly and time-consuming. We report our newly-acquired census results from field surveys and compare them with historical data on numbers and distribution changes of wintering A. cygnoides in the middle and lower Yangtze River floodplain. The basic information from this study may be useful in further advancing the conservation prospects of this species
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
