Search Results (46)

Understanding the impact of climate change on waterbirds, particularly those of conservation concern, is essential for their long-term management and effective conservation. In arid regions such as North Africa, wetlands of international importance have been affected by severe drought events, but their impact on waterbirds is still not well understood. Here, we assess the population dynamics of four emblematic resident species (Aythya nyroca, Marmaronetta angustirostris, Oxyura leucocephala, and Porphyrio porphyrio porphyrio) in a North African Ramsar site (Garaet Hadj Tahar marsh, Northeast Algeria), and determine the climatic variables (temperature, precipitation, and drought index) that best predict the change in abundance in wintering and breeding seasons. We used a long-term survey of regular counts during the wintering and breeding seasons of 2002–2019. The temporal trend of waterbird abundance differed between species and seasons. Species showed different sensitivities to different climatic variables at different time windows preceding the wintering and breeding seasons. We found that the population dynamics of the endangered O. leucocephala in the wintering and breeding seasons were best predicted with the drought index, whereas those of P. p. porphyrio were best correlated with maximum temperature. Population dynamics during the wintering and breeding season of the two other species were best explained with either maximum temperature, precipitation, average temperature, or drought. Species responded differently to warming and drought. The most endangered species (O. leucocephala) showed population declines in drier years, whereas less threatened species (A. nyroca, M. angustirostris, and P. p. porphyrio) exhibited either positive or negative correlations. The observed temporal increase in vegetation cover was positively correlated with the wintering population size of O. leucocephala, as well as the breeding population size of P. p. porphyrio and M. angustirostris. These findings highlight the urgent need for climate-adaptive conservation strategies to sustain wetland biodiversity and ecosystem resilience in the face of increasing climate stressors, aligning with the global sustainability goals for biodiversity conservation and ecosystem management. Our results suggest that future increases in temperatures and drought severity might threaten endangered waterbirds and benefit more common species in the region. Full article

The global degradation and loss of natural wetlands are increasingly threatening wetland-dependent taxa, particularly waterbirds, which are highly vulnerable to environmental changes. In response to these threats, an increasing number of waterbirds are relocating to surrounding satellite wetlands in search of compensatory habitats. However, how waterbirds utilize these satellite wetlands and respond to varying environmental variables remain poorly understood. In the winter of 2022–2023 and summer of 2023, we conducted surveys on waterbird assemblages in 49 satellite wetlands of different types (reservoirs, aquaculture ponds, paddy fields and natural ponds) surrounding Shengjin Lake, a Ramsar site, and analyzed the relationship between community metrics and environmental factors. Large numbers of waterbirds were recorded during both summer and winter, including several threatened and nationally protected species. Species richness and number of individuals varied significantly across wetland types, with aquaculture ponds supporting the highest number of species and individuals. These two metrics showed positive correlations with wetland areas and landscape connectivity in both seasons. Species richness was also positively correlated with habitat diversity in summer. The number of individuals was positively correlated with habitat diversity and negatively with distance to human settlements, but the pattern was in contrast to that in winter. The Shannon–Wiener diversity index displayed a similar pattern among wetland types in winter but did not in summer. We detected no effects of environmental factors on the diversity index. Species composition differed markedly between wetland types in both seasons, especially between reservoirs and aquaculture ponds. To safeguard waterbird communities in the middle and lower reaches of the Yangtze River, we recommend integrating surrounding satellite wetlands into the regional wetland network and reducing human disturbances, particularly during the winter months. Full article

As a habitat for waterbirds, wetlands are key to their survival, reproduction and development. Waterbirds usually prefer breeding, wintering and resting in fixed locations. Siberian cranes (Grus leucogeranus), which are highly dependent on wetlands, have long fed on farmland at migratory stopover sites. To explore the reason for this phenomenon, the time budgets of Siberian crane populations stopping over on farmland or in wetland habitats were studied and compared in this study. The results showed that the farmlands visited by the Siberian cranes are rich in food resources and have experienced low levels of disturbance. The temporal distribution of feeding behavior on farmland (53.50%) was greater than that in wetland habitats (31.96%). The variations in warning, flying and walking behavior on farmland were less than those in wetlands. The feeding efficiency on farmland was significantly greater than that in wetlands. Therefore, Siberian cranes transiting the Songnen Plain leave wetland habitats and stop over on farmland, representing a behavior that occurs more than just occasionally. Instead, they change their foraging habitat choices based on the optimal foraging theory. As a transit feeding area for Siberian cranes, farmland poses a significant risk, and the restoration of wetland habitats and food resources is still needed. This study can provide theoretical support for the conservation of rare and endangered species (the Siberian crane) and the management of stopover sites. Full article

In the context of global warming and intensified human activities, the loss and fragmentation of species habitats have been exacerbated. In order to clarify the trends in the current and future suitable wintering areas for hooded cranes (Grus monacha), the MaxEnt model was applied to predict the distribution patterns and trends of hooded cranes based on 94 occurrence records and 23 environmental variables during the wintering periods from 2015 to 2024. The results indicated the following. (1) The elevation (Elev, 43.7%), distance to major water (DW, 39.5%), minimum temperature of the coldest month (Bio6, 9.7%), and precipitation of the wettest month (Bio13, 2.6%) were dominant factors influencing the wintering distribution of hooded cranes. (2) Under current climate and land use scenarios, highly suitable areas for hooded cranes in China cover approximately 1.274 × 10⁵ km², primarily located in inland lakes such as Dongting Lake, Liangzi Lake, Poyang Lake, Shengjin Lake, and Caizi Lake in the middle and lower reaches of the Yangtze River, as well as in coastal wetlands such as Chongming East Beach, Shandong Peninsula, Bohai Bay, and Liaodong Peninsula. (3) Under future climate and land use scenarios, the suitable habitat areas (high and moderate suitability) for hooded cranes are projected to contract substantially in the middle and lower reaches of the Yangtze River and expand slightly in the areas of Shandong Peninsula, Bohai Bay, and Liaodong Peninsula. Under the SSP126 (low emissions), SSP245 (medium emissions), and SSP585 (high emissions) scenarios, the average area reduction percentages were 29.1%, 28.8%, and 31.6%, respectively. (4) The increases in Bio6 and water areas in northern China were the main reasons for the shift of the wintering distribution centroid for hooded cranes toward northeastern China. The minor expansion of suitable habitat in the north covers mainly cultivated land, and this singular foraging habitat could intensify both intraspecific and interspecific competition among waterbirds, thus exacerbating the survival risks for hooded cranes. To more effectively protect the wintering population of hooded cranes in China, the restoration of natural habitats and population monitoring in the middle and lower reaches of the Yangtze River should be strengthened. Additionally, nature reserves or protected areas should be established in the northern expansion regions. Full article

Understanding migratory routes is crucial for the conservation of birds and their habitats. Zhejiang is a crucial stopover and wintering area for birds in the East Asian–Australasian Flyway; however, detailed information on this area, and particularly on connections between coastal areas, is limited. By synthesizing ringed and recapture records from local bird-ringing projects and re-sighting community science data (208 records of 35 species), we established migratory connectivity between the Zhejiang coast and nine countries (i.e., Russia, Mongolia, the United States, Korea, Japan, Malaysia, Singapore, Thailand, and Australia), as well as eleven sites within China, and established its crucial role in this flyway. Stopover fidelity was verified by some species with high recapture frequency (seven species exceeded 1%) and species with duplicated re-sighted records (seven Black-faced Spoonbill, one Dalmatian Pelican, and two Spoon-billed Sandpiper individuals). We identified six areas—Hangzhou Bay, Aiwan Bay, Xuanmen National Park, Wenzhou Bay, the reclaimed area between the Ou and Feiyun Rivers, and the Wenzhou Jiangnan Reclamation Area—as crucial stopovers and wintering refuges for waterbirds. Notably, in Xuanmen National Park and the coastal regions along Wenzhou, there were many recovery records for flagship species, such as the Black-faced Spoonbill and Spoon-billed Sandpiper. There were several cases of the recovery of the same individual studied across the years. These findings indicate that these unprotected wetlands require particular attention. Broadly, our findings highlight the feasibility of integrating comprehensive ringing projects with citizen science data to formulate effective conservation strategies and underscore the critical importance of the Zhejiang Coast for migratory waterbirds, particularly those with high conservation concerns, emphasizing the need to mitigate the threats faced by these vulnerable populations. Full article

Habitat selection has been a central focus of animal ecology, with research primarily concentrating on habitat choice, utilization, and evaluation. However, studies confined to a single scale often fail to reveal the habitat selection needs of animals fully and accurately. This paper investigates the wintering whooper swan (Cygnus cygnus) in Manas National Wetland Park, Xinjiang, using satellite tracking to determine their locations. The Maximum Entropy model (MaxEnt) was applied to explore the multi-scales habitat selection needs of Manas National Wetland Park’s wintering whooper swans across nighttime, daytime, and landscape scales. This study showed that the habitat selection of the wintering whooper swans varied in different scales. At the landscape scale, wintering whooper swans prefer habitats with average winter precipitations of 6.9 mm and average temperatures of −6 °C, including water bodies and wetlands, indicating that climate (precipitation and temperature) and land type (wetlands and water bodies) influence their winter habitat selection. During daytime, whooper swans prefer areas close to wetlands, water bodies, and bare land, with a more dispersed distribution of water bodies. For nighttime, they tend to choose areas within the wetland park where human disturbance is minimal and safety is higher. This study can provide scientific basis and data support for habitat conservation and management of wintering waterbirds like whooper swans, recommending targeted conservation measures to effectively manage and protect the wintering grounds of whooper swans. Full article

Considering the negative effects of wetland degradation, various measures have been implemented to restore wetland habitats for aquatic organisms, and their effectiveness levels must be assessed. To reduce the effects of aquaculture on aquatic communities, pen culture facilities, which are widely distributed in Yangtze-connected lakes, were removed in 2018. We surveyed and compared waterbird communities in Caizi Lake during the four months before (2017–2018) and after net pen removal (2021–2022) to evaluate their effect on the diversity and species composition of wintering waterbirds. After net pen removal, the richness and number of individual waterbird species increased, whereas the Shannon–Wiener diversity index did not change because the increase in the bird number throughout the year was mostly associated with a few species. The response of individual numbers of different guilds to the removal of net pens differed. The number of deep-water fish eaters, seed eaters, and tuber feeders increased, whereas that of invertebrate eaters decreased. The species composition also changed, particularly in the northeastern and southwestern parts of the lake. Differences in waterbird communities between the winters of 2017–2018 and 2021–2022 indicated that net pen removal had a positive impact on waterbird communities. Full article

Moroccan wetlands host up to half a million wintering birds and provide a stopover for tens of thousands of migrants, while they are inhabited by few nesting species. Most of this avifauna prefers to use the large coastal wetlands or reservoirs, while many species are dispersed across hundreds of small inland wetlands of various types. In this study, we monitored the wintering avifauna of 11 wetlands of the Saïss plain and its adjacent Atlas Mountains (north–center of Morocco), during six wintering seasons (2017–2018 to 2022–2023), with the objective of assessing the importance of this region as a waterbird wintering area. Using the richness of the species, we determine the bird population changes during this pentad and between the different types of wetlands (natural, human-made, and natural wetlands). During this study, we recorded 51 species, belonging to 17 families, among which exist four remarkable birds: the endangered Oxyura leucocephala, the vulnerable Aythya ferina and the near-threatened Aythya nyroca and Limosa limosa. Bird diversity is higher in human-made ecosystems than in peri-urban and natural ecosystems, while the populations’ size is similar in urban and non-urban wetlands. With regard to bird conservation, these inland wetlands, mainly the small ones, are threatened by recurrent droughts and various anthropic stressors, which we describe using our observations of the two last decades (2003–2023). The loss of habitat is significant, reaching 348.5 hectares, while the impacts of reduced precipitation and temperature increase are particularly evident in the mountainous natural lakes. Full article

Wetlands are among the most important habitats of highly wetland-dependent waterbirds but are subject to ongoing habitat loss and degradation owing to intensified anthropogenic activities. The scarcity of human and natural resources makes effective habitat protection an important concern. Here, we aimed to investigate waterbird habitat protection methods for Anhui Province, China, a critical stopover and wintering area on the East Asian-Australasian Flyway that features rich wetland resources subject to significant habitat loss and degradation. We evaluated the status and importance of 306 wintering waterbird habitats and identified the key environmental influences and current protection gaps using the entropy weights method and generalized additive modeling. We found 73 important habitats for waterbirds in Anhui Province, which were classified into levels of importance (descending from I to V) according to the natural discontinuity method. Level I and Level II habitats were mainly located in the Yangtze River floodplain and Level IV habitats in the Huaihe River floodplain. The gap analysis showed that 42 important waterbird habitats had protection gaps, accounting for 57.53% of the total area. Waterbird habitat importance was significantly correlated with elevation, normalized vegetation index, lake area, and lake circumference but not with distance from roads or population density. The results of this study provide scientific information for waterbird habitat conservation planning, which is crucial for maintaining wetland ecosystem functions. Full article

This study was designed to determine the fragmentation of sub-lakes in winter and its effects on wintering waterbirds in Poyang Lake. Poyang Lake becomes fragmented in winter, which forms many seasonal sub-lakes every year, and have different environmental characteristics. These sub-lakes significantly impact winter bird habitats and result in susceptibility to various changes, because birds have different distribution responses. A total of 24 sub-lakes were surveyed from one to five vantage points using point count methods in each sub-lake with binoculars, monocular, and a spotting scope for four consecutive winter seasons. The multi-site dissimilarity Sorensen index measures overlapped between two populations, and the R software “iNEXT” package was used to evaluate the sample coverage test of the study area. We observed 58 wintering waterbird species belonging to 9 orders and 15 families from 2016 to 2020. Spearman correlation analysis showed that the species richness of wintering waterbirds was significantly positively correlated with the sub-lake areas and associated with the richness of habitat type. The WNODF analyses were considerably correlated for sites of waterbirds, mainly with the abundance of forage and conservation of habitat form. The outcomes of this study showed that Maying Lake has the highest local beta diversity, whereas Dacha Lake has the lowest local beta diversity contribution (0.007). This study’s findings demonstrate Poyang Lake’s role in waterbird the habitat suitability of waterbirds, especially for foraging and conservation. Full article

The edaphic and environmental changes in Bujagh grasslands have led to a gradual decline in the wintering waterbird populations in the associated national park. This has particularly affected forage habitats for birds, especially migratory geese. Our aim was to identify the reasons for the loss of habitat quality by examining the structure of the plant community and the edaphic factors that have been instrumental in shifting the grass community pattern to a Rush–Rubus type along the succession route. Bujagh National Park is surrounded by marine, riverine fresh water, and lagoon habitats, and the seasonal floodings of the Sefidrud and Ushmak rivers impact the grassland area along the deltaic pathway to the Caspian Sea. We used the TWINSPAN classification function to extract plant groups and their dominant species. Subsequently, we analyzed land cover changes in the study area over two times (2010 and 2020) to identify alterations in the coverage of main plants and land uses. Following the evaluation of unconstrained ordination methods and the selection of NMDS ordination, we compared the dominant species of groups to the main edaphic predictors. The results indicated that the chemicals and heavy metals in the soil did not play a direct role in the shift from grassland to Rush–Rubus plant type. However, these elements could have a significant impact on the evolution of the structure and the competitive capability among the main dominant species of the grass group. In conclusion, the dominance of the Rush–Rubus type is likely related to other unmeasured environmental and anthropogenic factors that support and enhance their reproductive attributes and herbal proliferation in the grassland territory. Full article

Global climate change has significantly impacted waterbird communities in the warming and humidifying wetlands of the Qinghai–Tibet Plateau. However, further research is needed as these wetlands transition to warmer and drier states. This study focused on the diversity and richness of wintering birds in the alpine wetlands of the Yamzho Yumco Lake. By analyzing data collected from 17 sampling sites over seven years, we examined the abundance changes of waterbirds in the lake and surrounding land and determined the relationship between the structure of waterbird communities and climate data. The results have shown that the abundance, richness, and α-diversity index of wintering waterbirds fluctuated. Wintering waterbirds were positively correlated with monthly mean temperature and monthly mean higher temperature and negatively correlated with monthly total precipitation and water level. Principal component analysis (PCA) showed that temperature contributed the most to the wintering waterbirds. Bird abundance and diversity in the drying wetlands of Yamzho Yumco Lake showed the same results. As temperatures continue to increase and precipitation decreases, the number of wintering waterbirds may also increase. We have highlighted the indicative role of Yamzho Yumco Lake in climate change responses from warming and humidification to warming and aridification and suggest that decision makers strengthen monitoring of the Yamzho Yumco Lake Reserve, restrict human activities, improve water resource management, and actively respond to the challenges brought about by climate change. Full article

Vertebrates and their gut bacteria interact in complex and mutually beneficial ways. The intestinal microbial composition is influenced by several external influences. In addition to food, the abiotic elements of the environment, such as temperature, humidity, and seasonal fluctuation are also important determinants. Fecal samples were collected from two captive duck species, Baikal teal (Sibirionetta formosa) and common teal (Anas crecca) across four seasons (summer, autumn, winter, and spring). These ducks were consistently fed the same diet throughout the entire experiment. High throughput sequencing (Illumina Mi-seq) was employed to analyze the V4–V5 region of the 16sRNA gene. The dominant phyla in all seasons were Proteobacteria and Firmicutes. Interestingly, the alpha diversity was higher in winter for both species. The NMDS, PCoA, and ANOSIM analysis showed the distinct clustering of bacterial composition between different seasons, while no significant differences were discovered between duck species within the same season. In addition, LefSe analysis demonstrated specific biomarkers in different seasons, with the highest number revealed in winter. The co-occurrence network analysis also showed that during winter, the network illustrated a more intricate structure with the greatest number of nodes and edges. However, this study identified ten potentially pathogenic bacterial species, which showed significantly enhanced diversity and abundance throughout the summer. Overall, our results revealed that season mainly regulated the intestinal bacterial community composition and pathogenic bacteria of captive ducks under the instant diet. This study provides an important new understanding of the seasonal variations in captive wild ducks’ intestinal bacterial community structure. The information available here may be essential data for preventing and controlling infections caused by pathogenic bacteria in captive waterbirds. Full article

Poyang Lake wetland in the middle and lower Yangtze River floodplain provides important wintering sites for migratory waterbirds. Extreme climatic events and human activities have resulted in the degradation and redistribution of habitat over the last few decades. However, the effects of habitat changes on the abundance of waterbirds remain unclear. We used long-term waterbird monitoring data and Landsat remote-sensing data to characterize changes in abundance and the relationship between habitat variation and abundance. A total of 113 waterbird species were recorded in the wintering period between 1999 and 2021, including 23 globally threatened species. Greater White-fronted Goose (Anser albifrons), Swan Goose (Anser cygnoides), Bean Goose (Anser fabalis), and Tundra Swan (Cygnus columbianus) were the dominant species. A total of 46 species with more than 6 annual surveys and average abundance >100 were recorded between 1999 and 2021. For most species, the mean abundance across all sub-lakes was higher in the first year than in the last year, and no obvious changes were observed over the last 20 years. The mean abundances of the vulnerable species Hooded Crane (Grus monacha) and White-naped Crane (Grus vipio) significantly declined between 1999 and 2021. No significant changes in the mean abundance of all foraging groups were observed. The area of water bodies increased, and the area of mudflats decreased. For most species with significant changes in abundance, habitat change did not greatly contribute to variation in mean abundance. The reduction in the area of mudflats greatly contributed to declines in the mean abundance of the gray heron (Ardea cinerea) and gadwall (Anas strepera). Full article

The Guizhou Caohai Wetland plays a crucial role as a wintering site for migratory birds in the Yunnan–Guizhou Plateau and ranks among the largest wintering spots globally for black-necked cranes (Grus nigricollis). To better understand the factors influencing waterbird populations and ecosystem changes, we conducted a comprehensive analysis of historical waterbird population variations over a 30-year period spanning from 1992 to 2022. The current investigation revealed a downward trend in the abundance index curve of the total number of waterbirds during this observation period. Among the five waterbird guilds examined, dabbling ducks, diving ducks, and coots (Fulica atra) experienced declines in their populations, while wading birds and shorebirds saw an increase. Moreover, we observed a rise in species richness within the community over time, accompanied by smaller compositional changes. Additionally, the findings indicated positive growth trends in wintering endangered species such as black-necked cranes and common cranes (Grus grus) in Caohai. Furthermore, we observed an increase in the occurrence and persistence of rare species, such as Eurasian spoonbills (Platalea leucorodia), black-faced spoonbills (Platalea minor), and black storks (Ciconia nigra) wintering in Caohai. These occurrences suggest that the wetland environment provides favorable conditions for a diverse range of species. Despite the rise in species richness, these trends in the abundance and species composition of wintering waterbirds over the past thirty years are still of concern. This study serves as fundamental scientific support for waterbird conservation and the restoration of ecological wetlands in the Guizhou Caohai Wetland. Full article