| Located in the northern part of Jiangxi Province, Poyang Lake Nature Reserve lies in the northwest of Poyang Lake, which is the largest freshwater lake in China. This nature reserve, which serves as a key over-wintering habitat for waterfowls, is considered as a vital part in the Asia-Australia migratory route. Since established in 1980s, there have been several investigations to the avian resources conducted by ornithologists, research institutes and international funds. Those investigations mainly focused on the endanger species and the distribution of waterfowls. For our part, a survey was conducted in purpose of finding out the dynamics of over-wintering white-fronted goose population, the typical wintering behaviors and the foraging spots selection strategies in Poyang Lake Nature Reserve from October 2009 to March 2011. The main results showed as follow:1,The migration dates of greater white-fronted geese colonies in Dahuchi Lake, Changhuchi Lake and Zhushihu Lake and the dynamics of the whole population were recorded from October 2008 to March 2011. The results showed that the wintering period in Dahuchi Lake was the longest among those three lakes, while the average wintering period lasted for 166.7 days. The population dynamics for greater white-fronted goose was in uni-modal distribution shape. The wintering period begins in October. Continue increasing, the largest wintering population comes into being during November and December, and then it gradually decreases. The wintering period finishes in March. Take the population in Dahuchi Lake as sample, it is found that the population dynamics of sample totally keep in step with that of the whole population. The colonies in Dahuchi Lake showed minor increase during the end of January to February.The water level at channel gate of the Dahuchi Lake and the local daily temperature were considered as ecological factors in research to the relationship between them and the colonies dynamics in Dahuchi Lake during the wintering period in 2009 to 2010. The result of Pearson correlation analysis shows that there was significant negative relationship between the water level and the local colonies dynamics (p=0.042,r=-0.514), while there was not significant correlation between daily temperature and the local dynamics.2,Investigation on the Carex grassland in the east bank of Dahuchi Lake, the west bank of Changhuchi Lake and the southeast bank of Shahu Lake were conducted in purpose of analyzing the diurnal rhythm of white-fronted geese's wintering behaviors from November 2010 to January 2011. The investigation usually starts at 7:00am, and finishes at 5:00pm. Using scanning sampling,523 samples were recorded. The results showed that there were active behaviors and inactive behaviors. The typical wintering behaviors include foraging, alerting, strolling, preening and resting, among which the foraging takes the largest proportion.A research to the alerting behavior was carried out. The result showed that there was significant correlation between the number of alerting birds and the whole population (one-way ANOVA). When the population was less than 100, there were 1-3 birds responsible for the vigilance. When the population was less than 200, the proportion of alerting birds was the largest. When the population was larger than 5000, there was no evident alerting bird. An artificial disturbance experiment was designed to measure the watching distance and fleeting distance of white-fronted goose. The result showed that both of the watching distance and fleeting distance was increasing with the disturbance rising up.A research to white-fronted goose's forage was carried out. Using random sampling, individual foraging behavior was survey constantly in lmin, and the foraging frequency was recoded. The results showed the high foraging frequency appeared during 9:30am to 10:30am and 1:30pm to 2:30pm.3,The habitat in Poyang Lake Nature Reserve was divided into 5 parts, including woods and farmland, reed shore, Carex grass shore, water-stand mudflat and water body. Occurrence rates for white-fronted goose were recorded in these habitats, among which the highest rate (93%) occurred in Carex grass shore.An investigation to the vegetation was conducted. The result showed the main plants include Carex, Potentilla, Polygonum, Phragmites, Triarrhena, Ranuculus. There are Triarrhena lutarioriparia-Carex association and Triarrhena lutarioriparia-Phragmites australis-Carex ovatispiculata-Potentilla tanacetifolia association.Using belt transects methods, there were 9 transects set on the Carex grass shore in Dahuchi Lake, Changhuchi Lake, Zhushihu Lake and the southeast bank of Shahu Lake. Each transect was divided into two parts.54 samples were collected on those transects. The density, height, coverage and the biomass per unit area of Carex were investigated. The results showed that there were significant difference in height, coverage, and biomass per unit area among samples with different density.4,Based on the results of research and investigations, the major treats to wintering greater white-fronted goose population in Poyang Lake Nature Reserve were:herbing in grassland, illegal hunting, industrial pollution, economic construction & development, ineffectiveness of protective measures. Relevant protection suggestions had been proposed upon those problems. |
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