Winter coexistence in herbivorous waterbirds: Niche differentiation in a floodplain, Poyang Lake, China

Abstract

The classical niche theory supports the idea that stable coexistence requires ecological differences between closely related species. However, information on waterbirds coexistence in the entirely landlocked freshwater system of Poyang Lake is not well understood, especially when the available biomass of their food in the area decreases.In this study, we tested the ecological segregation mechanisms in the 2015/2016 and 2016/2017 wintering periods among eight herbivorous waterbirds (including the Siberian crane Grus leucogeranus, hooded crane Grus monacha, white-naped crane Grus vipio, common crane Grus grus, greater white-fronted goose Anser albifrons, bean goose Anser fabalis, swan goose Anser cygnoides, and tundra swan Cygnus columbianus) at Poyang Lake. Using field observations and species niche and foraging habitat selection models, we investigated the abundance, distribution, and food sources of these eight waterbird species to quantify and compare their habitat use and ecological niches. Our results showed that niche segregation among the waterbirds, with respect to food types, time, and spatial location, allow them to coexist and use similar resources. The water level gradually receded in the sub-lakes of the Poyang Lake, which could provide food sources and various habitats for wintering herbivorous waterbirds to coexist. We demonstrated that the differences in habitat use could mitigate interspecific competition, which may explain the mechanism whereby waterbirds of Poyang Lake coexist during the wintering period, despite considerable overlap in the dietary niches of herbivorous waterbirds.

Dynamic simulation of the grassland connectivity and the effects of landscape pattern in China's Poyang Lake from the integrated perspective of habitat and biology

“…Nearly 98% of the world's white cranes, 50% of white‐naped cranes and 60% of swan geese live through winter in Poyang Lake (Zeng et al, 2018). The marshland is flooded when water rises in summer, while the marshland emerge when water falls in autumn and winter, and moist herbs grow rapidly and form vast grassland, which become the main habitat for wintering migratory birds and many unique species (Bai et al, 2021). Under the background of grazing prohibition policy implemented from 2008, the grassland is less disturbed by human activities, which provides an ideal experimental site for our study.…”

“…of the simulation of grassland connectivity coupled with ecological processes. and form vast grassland, which become the main habitat for wintering migratory birds and many unique species (Bai et al, 2021). Under the background of grazing prohibition policy implemented from 2008, the grassland is less disturbed by human activities, which provides an ideal experimental site for our study.…”

Diet drives the gut microbiome composition and assembly processes in winter migratory birds in the Poyang Lake wetland, China

“…One hundred and eighty samples from 17 species were frozen on dry ice immediately and then stored at -80°C until DNA extraction. Migratory bird species associated with feces samples were identified with the assistance of NJNR and DCNR protection station personnel based on methods described by Barter et al (2005) and a waterbird survey manual (Bai et al, 2021). Since the samples were collected by picking up the feces of migratory birds, the effects of age and gender on gut microbes were not considered in this study.…”

The Multi-Kingdom Microbiome of Wintering Migratory Birds in Poyang Lake, China

“…Poyang Lake, located in China, is the largest freshwater lake in the country and serves as a crucial stopover for migratory birds during their journey across the East Asian-Australasian Flyway. Generally, from October to March of the following year, migratory waterbirds from Siberia and Northeast Asia winter at Poyang Lake [ 3 ]. During this period, the lake experiences its dry season, resulting in a reduced water area predominantly composed of herbaceous meadows, mudflats, and isolated water bodies, facilitating pathogen spread [ 4 , 5 ].…”