The Population Viability Analysis, Distribution And Habitat Selection Of Chinese Water Deer(Hydropotes Inermis) In Poyang Lake

The Chinese water deer(Hydropotes inermis) in Poyang Lake is an isolated population which was one of the largest population of water deer in China. Due to the impact of changes of natural environment and human activities, the Chinese water deer populations showed a decreasing trend in Poyang Lake, Jiangxi.The China water deer has been less studied in Poyang Lake region. In history, the China water deer was once fairly abundant throughout Poyang Lake area. A few surveys showed that the number of China water deer populations was between 2 000 to 3 000 in Poyang Lake region in 1987. In recent years, its range and population size was seriously reduced due to flood, excessive poaching and habitat destruction.The general purpose of this study was to address the fundamental ecology of the China water deer in Poyang Lake region. Specifically, the three goals of the study were:(1) to present a qualitative distribution map and examine distribution patterns in Poyang Lake region;(2) to analyze patterns of habitat use indifferent period;(3) to compare the dynamic survival of Chinese water deer population in different scenario by population viability analysis(PVA).PVA: We collected the population parameters of this water deer population and the potential determinant factors on this population from published literatures, and conducted population viability analysis for Chinese water deer in Poyang Lakes. We predicted the population dynamics in 100 years by VORTEX 9.99 model. The results indicated that the extinction probability of this population would be 0.37 in the next 100 years. However, the extinction probability would increase substantially if its habitat was to be further destroyed. The high mortality of offsprings would result in the extinction probability up to 100% in the next 100 years. The population is sensitive to disasters, and the extinction probability would be higher if the flooding frequency continues increasing.Distribution: in flood season,the Chinese water deer was mainly distributed in Jishan Island and Jiniu Island, and a small part of the population were in the Wucheng Island and Xizhang in Poyang Lake National Nature Reserve. In dry season, the Chinese water deer was mainly distributed in glassland and did not use the habitats in islands within the Poyang Lake National Nature Reserve and Nanjishan Wetland National Nature Reserve.Habitat selection: we analyzed the potential impact of ecological factors such as vegetation type, vegetation height,vegetation coverage,distance to main road,and distance to main human disturbance. The results indicated that a significant different among vegetation type, vegetation height and vegetation coverage. In flood period,Chinese water deer showed preferred to bush fallow and grass fallow, vegetation height ranging from 90 to100 cm,and vegetation coverage >90%. In dry period,the Chinese water deer preferred to Phragmites australis, Triarrhena lutarioriparia, vegetation height ranging from 0 to 30 cm and >80 cm,and vegetation coverage ranging from 40% to 80%.Seasonal movements of Chinese water deer between the flood and the dry season were mainy caused by the water level change of the Poyang Lake. The Chinese water deer moved to the island in flood period,and moved to the grassland in dry period which have different habitat selection pattern during different periods.