Wading Bird Habitat, Water Depth Utilization and Niche Separation in Poyang Lake, China
Wading Bird Habitat, Water Depth Utilization and Niche Separation in Poyang Lake, China
Zhi Yijin, Shao Mingqin* and Li Quanjiang
ABSTRACT
From October to December 2018, and March to May of 2019, habitat, water depth utilization and niche separation of wading birds in Poyang Lake, China, was assessed. A total of 38 bird species, including 4 class I and 3 class II Chinese nationally protected bird species were identified. Of six habitats, 64% (15,435 individuals) of the total number of wading birds counted occurred in water-covered areas. The common crane Grus grus has the widest habitat niche (0.727), utilizing grasslands and farmland after crops were harvested, where it ate vegetation (roots) or seeds. Shorebirds have narrow habitat niches, and are limited largely to shallow water areas. Of species pairs, the pied avocet Recurvirostra avosetta and Eurasian spoonbill Platalea leucorodia have the highest habitat niche overlap, as their diet and foraging pattern are similar; these two species reduce competition by foraging in different areas. Three small-sized shorebirds are recorded in each water depth category. Both spotted redshank Tringa erythropus and common greenshank Tringa nebularia have high water depth niche breadth (> 0.7), with high tolerance to water level variation; both species segregate spatially to reduce competition. Of mid- and large-sized wading birds, the Eurasian spoonbill prefers V-grade waters and has a narrow water depth niche breadth. The water depth overlap of these mid- and large-sized wading birds ranged from 0 to 0.691. Grey heron Ardea cinerea, Eurasian spoonbill, and the common crane are spatially or trophically separated in Poyang Lake. We conclude with suggestions for improved wading bird conservation and habitat management in and around Poyang Lake.
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December 2020
Vol. 52, Iss. 6, Pages 2027-2426
