Quantify Wetland Bird Habitat Selection in Urban Environment

Background: As the importance of wetlands is recognized by society, the awareness of protecting wetlands is gradually awakening. Wetland conservation actions have been taken around the world, which brought the upsurge of urban wetland construction. However, the lack of research on habitat selection of wetland species results in poor construction or restoration of wetlands habitat in cities. The aims of this work are: (1) to unveil main factors affect habitat selection for the egrets dwelling and foraging. (2) to quantify their preference of habitat factors natural and urban wetland at multi scale. Methods: Quadrat sampling are used to collect the data of habitat factor selection. Factor analysis and component analysis for the preference and the difference of habitat selection in natural and urban wetland.Results: Guarding and flushing distances of egret were longer in natural wetland than those in constructed wetland. Difference significance tests of egret perching habitat factors showed that the habitat factors as distance from disturbed area, vegetation density, vegetation coverage, slope, distance from water surface, were striking (P〈0.05). In natural wetland and constructed wetland, the differences of three habitat factors including distance from disturbed area, ground coverage and vegetation coverage were striking (P〈0.05). PCA (Principal Component Analysis) extracted two principal components—distance factor and vegetation factor. Vanderloeg and Scavia coefficient analysis results suggested that Egrets intended to inhabit at areas with gentle slope, dense vegetation, wide forest belt, short distance from water surface, long distance from disturbed area, and forest near a fork estuary. They preferred to selected farmlands, fishponds, rivers, and shallows as their foraging sites in natural wetland, while in artificial environment the requirement for distance from disturbed area and hiding cover were loosened. The shoals of artificial rivers and lakes in urban wetlands are their choice. Conclusion: This study suggest that distance and vegetation were two principal components for egrets dwelling habitat selection. The disturbance distance from human was the most limiting factor for egret habitat selection in urban wetlands.