| Wetland ecosystems are a natural complex with integrated features of both land and water. These ecosystems have remarkable benefits in economy, society and landscape ecology. Waterfowl are not only an extremely sensitive indicator species of ecological environment of wetlands, but also a sight with aesthetical appreciation. This study conducted surveys of egret habitat selection in three wetland parks including Gouxihe, Huanhuaxi and Bailuxi by using methods like quadrat sampling and factor analysis; then it explored the main impact factors of egret habitat selection for their perching and foraging; and compared differences of their ecological behaviors and habitat selection in natural wetland with those in constructed wetland. The research could provide relevant basis for ecological restoration of natural wetland, egret attraction in constructed wetland, as well as animal landscape construction. Results indicated that:Guarding and flushing distances of egret were longer in natural wetland than those in constructed wetland, which suggested that egret had better tolerance due to human activity disturbance, and they shortened guarding and flushing distances in constructed wetland. Difference significance tests of egret perching habitat factors by using Kolmogorov-Smirnov test, T-test, and Mann-Whitney U-test, showed that in both experimental samples and control samples, the differences of such five habitat factors as distance from disturbed area, vegetation density, vegetation coverage, slope, distance from water surface, were striking (P <0.05). When egret selected perching habitat, they followed their own nature, preferring a habitat with gentle slope, dense vegetation, wide forest belt, short distance from water surface, long distance from disturbed area, and forest near a fork estuary. 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). In constructed wetland, distance from disturbed area was the most limiting perching habitat factor, which greatly influenced utilization of the space with unrestricted resources. All the samples were analyzed by PC A (Principal Component Analysis) which extracted two principal components—distance factor and vegetation factor. These two factors had eigenvalue greater than 1 and cumulatively contributed to 82.42%. Selection index of experimental samples and control samples of egret foraging habitat were tested by Vanderloeg and Scavia selection coefficient. Results suggested that in natural wetland, egret selected farmlands, fishponds, rivers and shallows as foraging sites, and they preferred areas where there was water with large surface and depth of less than 30cm (not above their tarsometatarsus with the lowest feather cover), distance from disturbed area was more than 60m or cover degree was more than 0.5, distance from perching sites was less than 1000m, and distance from rivers was less than 300m. Egret in constructed wetland, compared with those in natural wetland, selected shoals of artificial rivers and lakes as their foraging sites, which reduced requirements for distance from disturbed area and cover degree.The suggestion of attracts egrets in the artifical wetland is building theropencedrymion which ground line gradient <0.1,distance to the human disturb <20m, distance to surface water <20m, vegetation degree of cover> 0.5, vegetation density> 0.3/m2 (Banboo forest would <30/m2), forest belt width> 30m and forest belt length> the 100m as habitat.And building shoal waters area which water depth <0.3m, distance to the human disturb>60m, distance to the habitat <2000m as foraging site. |
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