1) 생물학 & 생태학
2) 보전 & 관리
3) 조류 인플루엔자 / 그 외
1) 생물학 & 생태학
Mohd Ros Effendi , Mohammad Saiful Mansor
Abstract: Vanellus vanellus (Linnaeus, 1758) (Aves, Charadriidae), Northern Lapwing, is listed as Near Threatened by the IUCN due to declines in the availability of its habitat since 1980. The species is a widespread Palearctic breeder and an uncommon migrant to Southeast Asia, where it winters in Thailand and Vietnam. We document the first recorded sighting of V. vanellus in Malaysia, marking the southernmost occurrence of the species to date.
Mengdi FU , Jun WANG , Chunfei HOU , Junsheng LI , Jiade BAI , Yuanyuan ZHANG
Abstract: The coastal wetlands of the Bohai Rim region in China serve as critical habitats for breeding, migratory stopovers, and wintering birds along the East Asian-Australasian Flyway. This study surveyed waterbird diversity across 17 coastal wetlands in the Bohai Rim region from 2018 to 2023 to identify community composition, analyze spatial and temporal patterns, and examine the key factors influencing waterbird diversity across various wetland types. A total of 133 species belonging to 18 families and 8 orders were recorded, with migratory species comprising 85.71 % of the total. Scolopacidae, Charadriidae, and Laridae exhibited the highest species richness and abundance, respectively. The number of waterbirds and diversity indices displayed a fluctuating but overall upward trend during the study period. Estuarine wetlands had the highest waterbird diversity, tidal wetlands exhibited the greatest bird density, whereas shallow sea and island wetlands showed comparatively lower diversity and evenness. The primary factors influencing waterbird diversity, ranked by significance, were PM2.5 concentration, vegetation coverage, macrobenthic biodiversity, regional population density, and temperature. High PM2.5 concentrations were significantly associated with reduced waterbird diversity, whereas higher vegetation coverage promoted diversity by improving habitat complexity. Macrobenthic biodiversity influenced food web dynamics via predation and competition, leading to a marginally negative impact on waterbird diversity. Regional population density significantly impacted waterbird diversity in island and tidal wetlands, highlighting the necessity of establishing and managing protected areas to sustain waterbird diversity. Additionally, increased precipitation caused by climate change alters wetland water levels, indirectly impacting habitat conditions for waterbirds. Improved wetland management and pollution control are essential for preserving waterbird diversity. This study provides important insights into how air pollution, water pollution, and climate change affect waterbird diversity, emphasizing the importance of integrated management strategies for maintaining coastal wetland ecosystem stability and the health of waterbird communities.
Zhu, Shiying; Deng, Guangyi; Jiang, Haibo; Gao, Jie; He, Chunguang; Zhang, Yan; Cao, Yingyue
Abstract: 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.
Sub Hur , Dae-Woo Kim , Jong-Gil Park , Hae Rim Lee , Young-Jun Kim , Bae-Keun Lee , Dong-Ha Nam
Abstract: Diving birds, particularly those sharing coastal habitats with fishing grounds, are at risk from oil pollution. Despite documented cases of bird mortality, the specific role of oil pollution in these death remains unclear. To address this knowledge gap, this study examined polycyclic aromatic hydrocarbon (PAH) contamination, its sources, and its impact on loon health. An analysis of 86 carcasses from three species of loons revealed drowning as the leading cause of death, followed by oil pollution and unknown debilitation. While liver concentrations of 16 PAHs (∑PAHs) showed no significant variation by sex, location, species, or cause of death, it was evident that wintering loons were exposed to PAH pollution along South Korea’s eastern coast. The ratio of low (di- and tri-cyclic) to high (tetra-, penta-, and hexa-cyclic) molecular weight PAHs was approximately 3–5 across all three loon species. From 2010 to 2017, the composition of PAHs shifted, with a decline in low molecular weight PAHs (indicative of petrogenic sources) and a concerning increase in high molecular weight PAHs (associated with pyrogenic sources). This trend coincided with a tenfold increase in the toxic equivalency quotient of benzo[a]pyrene (TEQBaP), despite a decrease in overall ∑PAH concentrations. The detection of benzo[a]pyrene diol epoxide (BPDE)-DNA adducts in some loons further suggests potential genotoxic effects from PAH exposure. These findings underscore the persistent PAH contamination affecting wintering loons. Continued research is crucial to understand the evolving threats posed by PAHs and to support the conservation of these migratory birds along the North America-Asia flyway.
Junjie Zhang , Lara Cioni , Veerle L.B. Jaspers , Alexandros G. Asimakopoulos , He-Bo Peng , Tobias A. Ross , Marcel Klaassen , Dorte Herzke
Abstract: Per- and polyfluoroalkyl substances (PFAS) have gained significant global attention due to their extensive industrial use and harmful effects on various organisms. Among these, perfluoroalkyl acids (PFAAs) are well-studied, but their diverse precursors remain challenging to monitor. The Total Oxidizable Precursor (TOP) assay offers a powerful approach to converting these precursors into detectable PFAAs. In this study, the TOP assay was applied to samples from the East Asian-Australian Flyway, a critical migratory route for millions of shorebirds. Samples included shellfish from China’s coastal mudflats, key stopover sites for these birds, and blood and liver samples from shorebirds overwintering in Australia. The results showed a substantial increase in perfluorocarboxylic acids (PFCAs) across all sample types following the TOP assay, with the most significant increases in shorebird livers (Sum PFCAs increased by 18,156 %). Intriguingly, the assay also revealed unexpected increases in perfluorosulfonic acids (PFSAs), suggesting the presence of unidentified precursors. These findings highlight the need for further research into these unknown precursors, their sources, and their ecological impacts on shorebirds, other wildlife, and potential human exposure. This study also provides crucial insights into the TOP assay’s strengths and limitations in studying PFAS precursor dynamics in biological matrices.
Jinjie He , Chang Wang , Ying Han , Wen Zhang , Yucheng Yang , Li Guo , Fengli Li
Abstract: The Liaohe River Estuary (LRE) wetland is a critical stopover on the East Asian-Australasian Flyway (EAAF), vital to coastal ecological balance and biodiversity. However, the drivers of changes in waterbird diversity remain unclear. This study utilised random forests to produce reliable time-series wetland mapping from 2010 to 2023. Spatial and temporal changes in wetlands and landscape structures were analysed using landscape pattern indices—the Alpha and Beta diversity analyses were based on monitoring records that assessed waterbird diversity and community structure. The response of waterbirds to wetland, landscape, and climate changes was quantified using a Generalized Linear Mixed Effects Model (GLMM). Between 2010 and 2023, 78 species of waterbirds from 8 orders and 14 families were recorded. In 2023, waterbird counts reached 1,014,908, marking an increase of 868,102 compared to 2010. Over 14 years, waterbird diversity consistently increased, with community structure becoming more stable. Positive responses to climatic factors, such as seasonal precipitation and mean temperatures (both year and seasonal), were observed, while extreme weather inhibited recovery, like heavy precipitation and strong winds. Changes in Suaeda salsa (Sua) and forested areas significantly impacted waterbird diversity compared to other land cover types. These findings highlight the strong influence of climate, wetland, and landscape changes on waterbird diversity and community structure. Managers are encouraged to prioritise monitoring temperature, precipitation, Sua, and forested landscapes while enhancing artificial wetland management to support waterbird diversity and ecological balance in the LRE.
Flexible host–microbe interaction aid adaptation of black-necked crane to seasonal shifts
Ruifeng Ma , Shujuan Ma , Yujia Zhang , Lei Hu , Keyi Tang , Hongyi Liu , Ke He , Yudong Li , Suolangduoerji , Ying Zhu
Abstract: To elucidate how hosts adapt to changing environments with the assistance of symbiotic microorganisms, we must first understand host–microbe interactions. However, the covariation patterns of gut microbiota and hosts under complex natural conditions are poorly understood. To address this gap in our knowledge, we used metabarcoding of plant RbcL and animal COI regions, along with bacterial 16S rRNA gene and metagenomic analyses. This enabled the analysis of the interactions between the gut microbiota of the black-necked crane (Grus nigricollis), a large migratory bird, and its plant and animal diets to be analyzed. The impact of these interactions on the adaptive strategies of the black-necked crane during different periods in the Zoige wetland, China, was also assessed. We found that the black-necked crane harbored more gut bacterial communities and more diverse plant-derived foods during the post-breeding period than during the pre-breeding period. The gut microbiota and diet covaried throughout the breeding season and exhibited seasonal patterns. Araneae and Cyperaceae were correlated with pre-breeding bacterial profile, whereas Acrididae and Elaeagnaceae were associated with post-breeding bacterial abundance. Sample microbiota distance (between-sample diversity) increased with increasing animal and plant diet distance, and this relationship was enhanced between the plant diet and gut microbiome, with a greater value observed during the pre-breeding period than during the post-breeding period. According to Simpson’s indexes, the gut microbiota was also positively associated with the plant-based diet across the seasons. The plant diet–microbe co-occurrence network was more complex than the animal diet–microbe network. The gut microbiota functional profile revealed that several amino acids, folate, lipids, and metabolic pathways were more abundant during the pre-breeding period, which enriched the nutrient resources of the black-necked crane prior to breeding. In contrast, carbohydrate metabolism was more abundant during the post-breeding period, which helped the black-necked crane to accumulate energy for its upcoming migration. These results suggest flexible host-microbiome-host relationships in two seasons and that host physiological needs interact with foraging strategies to shape the microbiome, ultimately resulting in host adaptations to seasonal shifts. These results provide insights into the role of the gut microbiota in host adaptations to seasonal changes under natural conditions.
From sky to ground: decoding migratory bird’s habitat selection along the multi-scale sequence
Xueman Xing , Fawen Qian , Keming Ma
Abstract: ContextMigratory birds select habitats by observing landscape patterns at different scales as they descend from higher elevations, weighing habitat availability. Understanding how this selection process operates at multiple scales and how decisions at different scales interact is crucial for identifying the optimal scale for efficient habitat conservation.ObjectivesWe aimed to investigate the regularity of changes in migratory birds’ habitat selection in response to landscape variables over multi-scales, using the Oriental White Stork (Ciconia boyciana) as an example.MethodWe developed Scale Response Models and Habitat Selection Models using a sequence of nine scales (5-200 km) within the East Asian-Australasian Flyway to evaluate the stork’s scale-sensitivity and assess the change of explanatory power of landscape variables across scales at different periods.ResultScale-sensitivity of storks was highest during the wintering period. The explanatory power of the suitable habitat indicator is higher at larger scales, but decreases with decreasing scale; while the opposite is true for the unsuitable habitat indicator. At large scales, wetland indicators dominated in breeding period, while water indicators dominated in other periods; at smaller scales, unsuitable habitat indicators had stronger impacts in wintering period.ConclusionsWe revealed a nested relationship in multi-scale habitat selection among storks: “benefit-tendency” decisions at larger scales provide context and constraints; “risk-avoidance” decisions at smaller scales determine settlement. Due to internal and external factors, migratory birds displayed different scale-sensitivities and landscape preferences across periods. Our findings highlight the scale-dependence of organisms’ behavior and landscape characteristics, providing guidance for multi-scale habitat conservation.
Wei Liu , Cheng Zhao , Pengfei Zhang , Ting Liang , Qifeng Huang , Yan Liu , Xiaoshou Liu
Abstract: Microplastic pollution has emerged as a significant environmental concern at the global level, potentially threatening biodiversity conservation and human wellbeing. As an important biological group with a wide global distribution, migratory shorebirds face considerable stress due to plastic and microplastic pollution. However, few studies have explored the ecotoxic impact of microplastic pollution on migratory shorebirds. To investigate the physiological effects of microplastic pollution on migratory shorebirds, this study obtained the morphological data of 79 dunlins at a key stopover site at the midpoint of the East Asian–Australasian Flyway in 2023 autumn. Meanwhile, fecal and blood samples were collected to examine the microplastic abundance accumulated in the body and metabolic levels. Microplastics were detected in 100 % of dunlins, comprising 12 distinct polymer types. The average abundance of microplastics ingested by dunlins was 134.50 items/g, which was higher than the reported abundance of environmental sediment. The present study confirmed that individuals with longer bills ingested more microplastics, resulting in significantly decreased body mass for the same shorebird. Compared to the low contamination group, metabolomic analysis also revealed that dunlins with elevated microplastic contamination exhibited the down-regulation of 10 metabolic pathways, including pyrimidine metabolism, beta-alanine metabolism, and vitamin C metabolism. The findings of this study underscore the potential threat microplastics pose to the health of migratory shorebirds. It is recommended that synergies be developed between microplastic management and biodiversity conservation at global and regional scales, with migratory birds serving as pivotal indicator species.
Li, David; Khoo, Max De Yuan; Lanctot, Richard B; Tomkovich, Pavel S; Ma, Zhijun; Chow, Jun Rui; Soh, Malcolm Chu Keong; Yang, Shufen; How, Choon Beng; Loo, Adrian
Abstract: Shorebird populations are declining across the world due to factors such as habitat loss and climate change. Identification of shorebird migration routes and important stopover sites can facilitate the implementation of strategic and effective conservation measures. Using a satellite transmitter, we successfully tracked the migration of one Grey Plover (Pluvialis squatarola) from its wintering grounds in Singapore north along the East Asian‐Australasian Flyway (EAAF) to its breeding grounds located east of the Taymyr Peninsula in north‐central Siberia. This provides the first evidence that the Singapore plover could be part of the Yamal/Taymyr population that is known to only migrate south via the East Atlantic Flyway and winter in Western Europe. After breeding, the bird took an unexpected westward migration towards northwestern Taymyr Peninsula where it stopped at two locations for 9 and 5 days, respectively, before migrating south through Central Asia. Prior to crossing the Himalayan mountains, however, the plover migrated east again from the Xinjiang Autonomous Region in northwest China to Jiangsu Province along the Yellow Sea, before turning south again to migrate along the EAAF to return to its wintering ground in Singapore. The plover’s westward post‐breeding migration was contrary to prevailing winds, while the eastward migration north of the Himalayas was facilitated by strong easterly winds. The plover’s westward migration post‐breeding may be attributed to acquiring additional food resources prior to its southward migration, and/or because it was searching for future breeding or staging grounds. Both possibilities may be associated with habitat changes occurring on their breeding grounds due to climate change. Further studies on the Grey Plovers wintering in Southeast Asia are needed to understand whether the migration route taken by this individual is representative of the species.
Responses to extreme drought in wintering waterbirds: a multi-species approach
Chenxi Wang , Shaoxia Xia* , Xiubo Yu and Li Wen
Abstract: Background Climate change and anthropogenic activities are accelerating environmental changes, challenging wild animals’ survival. Behavioral plasticity, such as adjusting habitat selection and foraging activity, is a key mechanism for responding to rapid environmental changes in the Anthropocene era. However, this shift may expose animals to new challenges. Moreover, not all behavioral plasticity is adaptive, as evidenced by ecological traps. This study focuses on Poyang Lake, a Ramsar wetland and a critical wintering ground for waterbirds in the East Asian–Australasian Flyway. Historically, the migratory patterns of waterbirds were synchronized with the plant life cycle. However, recent hydrological regime changes have diminished suitable habitats and food resources, thereby posing significant conservation challenges for waterbirds. Methods Utilizing multiyear satellite tracking data, we examined the variations in wintering home range and behaviors of four herbivorous waterbird species between natural and artificial wetlands in Poyang Lake under different hydrological conditions. Results Our results reveal significant differences in home range area and movement speed among species and across hydrological years. All species demonstrated a marked increase in their use of artificial wetlands under unfavorable conditions. Specifically, the Greater White-fronted Goose (Anser albifrons) shifted its distribution to artificial wetlands during drought years while favoring natural wetlands under normal conditions, indicating a stress-induced adaptation. In contrast, the Bean Goose (A. fabalis) and Swan Goose (A. cygnoid) displayed greater behavioral plasticity. Notably, the Siberian Crane (Leucogeranus leucogeranus) increasingly used artificial wetlands, likely due to human protection, raising concerns about potential ecological traps. Additionally, waterbirds foraging in artificial wetlands generally exhibited higher movement speeds during drought conditions. This behavior suggests maladaptation and a more dispersed distribution. Conclusions Our study underscored the critical role of artificial wetlands in supporting migratory waterbirds during drought, though elevated movement speeds observed in these habitats suggest potential maladaptation. Species-specific responses raise concerns about ecological traps if these habitats fail to meet key ecological needs. To ensure long-term conservation, efforts should focus on preserving natural wetlands and enhancing the quality of artificial habitats. Future research should prioritize long-term monitoring to guide habitat management and address species-specific needs in the face of climate change and habitat degradation.
Satellite tracking data reveal the underestimate population size of the ground survey
Wang Chenxi, Xia Shaoxia, Yu Xiubo & Wen Li
Abstract: The population of East Asian geese along migration routes is declining. Accurate understanding of the spatial distribution of wintering geese and estimates of their population numbers are vital for their conservation. Based on satellite tracking data, the migration timing and spatial distribution of geese in Poyang Lake were studied by using time series and home range analysis. We propose a method for estimating goose populations to address the population underestimation in current ground surveys. We found that the utilization intensity of geese is higher within the Protected area than outside, and during the wintering period, spatial overlap in their distributions is evident. This is especially the case in mid-winter, when the overlap area reaches 257.84 km2. There are missing areas in existing ground surveys, resulting in underestimation of the numbers of Greater White-fronted Goose, Bean Goose and Swan Goose by 13,196, 6157 and 3191, respectively. A reevaluation of the numbers using integrated satellite tracking and ground survey data, indicates the high level of importance of Poyang Lake for the protection of East Asian geese, with the numbers of Greater White-fronted Goose, Bean Goose, and Swan Goose wintering there constituting 56.94%, 14.53%, and 49.93%, respectively, of their estimated populations along the migration flyway. This study provided a scientific foundation for the conservation of East Asian geese populations and offers critical support for the development of targeted conservation strategies in the future.
Yang Wu , Weipan Lei , Entao Wu , Han Pan , Yifei Jia , Cai Lu , Yongxiang Han , Junjie Wang , Rong Fan , Zhijun Ma , Zhengwang Zhang , Richard A. Fuller
Abstract: Understanding the population dynamics of migratory species is crucial for their conservation. However, researchers often encounter challenges due to insufficient data, especially when monitoring migratory species throughout their annual cycle. One solution to this issue is to combine multiple types of data. Here we develop and test such an approach, using the Pied Avocet, a migratory waterbird species in East Asia, as a case study. We integrate count data, presence-only records, satellite tracking data, and species distribution models.
Our findings reveal an 85 % increase in the annual population of Pied Avocets in East Asia over the past 13 years, despite inconsistent trends across their four major wintering sites. Tracking data indicated that the species experiences low migratory mortality and a moderate to high overall survival rates, with survival not differing significantly between first-year birds and adults. We estimated a 109 % increase in suitable wintering habitat extent and a 42 % increase in breeding habitat extent for Pied Avocets over the past 20 years. These changes are primarily attributed to the proliferation of artificial wetlands, with climate change also contributing to the expansion of wintering habitats.
We conclude that multi-dimensional sources of evidence can be combined to assess and explain population changes even though data of any particular type are relatively limited. We emphasize the effectiveness and importance of using diverse methods to obtain comprehensive information on the population dynamics of migratory species, while concurrently establishing and improving long-term monitoring networks.
Xingpei Cao , Yang Wu , Furong Bai , Xiaobo Zheng , Weipan Lei , Zhengwang Zhang , Bi-Xian Mai
Abstract: Bohai Bay is an important stopover on the East Asian-Australasian flyway (EAAF) for migratory birds. In the present study, eggs of three migratory waterbird species, Little Terns (Sterna albifrons), Pied Avocets (Recurvirostra avosetta), and Black-winged Stilts (Himantopus himantopus), and local aquatic organisms from Bohai Bay (Nanpu and Dongying wetlands) were collected to determine stable isotope (13C, 15N, D) signature and concentrations of mercury (Hg), polychlorinated biphenyls (PCBs), dichlorodiphenyltrichloroethane (DDTs), and short-chain chlorinated paraffins (SCCPs). Organisms from Nanpu had significantly higher δD values than Dongying, which was related to local salinity. The pollution profiles showed species-specific difference in the same site, but no spatial difference for the same bird species from two wetlands. Positive correlations were observed between δ15N values and concentrations of Hg and PCBs, but not DDTs and SCCPs, because of the complex pollution sources in migration routes. The pollution exposure in the annual life cycle for Pied Avocets based on migration route information suggests that Hg and PCBs in eggs mainly originate from the breeding site (Bohai Bay), while DDTs are mainly from the wintering sites (the middle and lower reaches of the Yangtze River). Pollutants could pose considerable negative effect on eggshell thickness. The present study promotes the importance of pollutant exposure and risk assessment in the entire migration cycle for migratory birds.
Three subspecies of Black-tailed Godwit share non-breeding sites in the world’s largest river delta
Delip K. Das , Wouter M.G. Vansteelant , Bingrun Zhu , Shariful Islam , Naim Khandakar , Marco van der Velde , Chris J. Hassell , Jesse R. Conklin , Pierrick Bocher , Jos C.E.W. Hooijmeijer , Yvonne I. Verkuil , Theunis Piersma
Abstract: During the non-breeding season (September–April), Black-tailed Godwits (Limosa limosa) are commonly seen in coastal and inland wetlands of the Ganges-Brahmaputra-Meghna Delta in Bangladesh. We hypothesize that the Ganges-Brahmaputra-Meghna Delta, at the overlap between the Central Asian and East Asian–Australasian flyways, may host three subspecies that breed in disjunct areas of temperate and northern Asia: L. l. limosa, L. l. melanuroides, and L. l. bohaii. We used mitochondrial DNA (mtDNA) haplotype network and biometric analysis to determine subspecies in captured individuals, and deployed GPS–GSM transmitters to verify breeding areas of individuals with subspecies assignments. To test for differential habitat preferences, we sampled birds at two ecologically distinct habitats known to host the largest concentrations of non-breeding Black-tailed Godwits in Bangladesh: Nijhum Dweep National Park, a tidal coastal habitat with brackish water on the south-central coast, and Tanguar Haor (‘backmarsh’), a seasonal freshwater floodplain in the north. During the non-breeding seasons of 2021–2022 and 2022–2023, we sampled and measured 93 Black-tailed Godwits, 54 of which were equipped with GPS–GSM transmitters. Our mtDNA haplotype network analysis confirmed the presence of limosa, melanuroides, and bohaii subspecies at the study sites. Thus, indeed, Black-tailed Godwits subspecies, despite having distinct breeding ranges, exhibit (partially) overlapping non-breeding ranges in Asia. The subspecies composition differed significantly between sites, with limosa and bohaii dominating in Tanguar Haor and melanuroides in Nijhum Dweep. Of the 21 individuals that were tracked to their breeding grounds, 18 migrated to the expected breeding range of their respective subspecies. However, one bird with a limosa haplotype migrated to a known breeding area of bohaii, whereas two birds with melanuroides haplotypes migrated to the supposed breeding range of limosa. Therefore, while ecological factors at both ends of the flyways may shape the morphological and behavioural differences between Black-tailed Godwit subspecies, their delineations and possible gene flow require further studies.
Impact of duck predation on the population of Manila clam (Ruditapes philippinarum) in tidal flat
Rikuto Honda , Takehisa Yamakita , Tatsuya Ozaki , Nana Yamashita , Tomohiro Komorita
Abstract: Ducks such as mallards (Anas platyrhynchos), have been the target of predation control, including extermination efforts, on land and in coastal regions, because they fly in colonies and prey on a wide variety of agricultural crops and marine products, including Manila clams (Ruditapes philippinarum). To date, stomach content analysis and behavioral observations have primarily been used to assess duck predation on clams. Although ducks appear to respond to water depth, their response to short-term changes in water depth (i.e., tidal height) has not been assessed in tidal flats. Therefore, a quantitative evaluation of the effects of duck predation on clams is needed to clarify the behavior of ducks on tidal flats and to conserve ducks and clams. In this study, the influence of duck predation on the clam population was investigated using anti-predation experiments on the Midorikawa River tidal flat in Ariake Bay, Kyushu, Japan. Furthermore, the relationships among water depth, duck activity, and duck flock density were investigated using a trail camera and a drone. In the anti-predation experiment during the study period, no significant difference in clam density was found between the experimental and control clam density. This study showed that duck predation may have a small impact on the Manila clam population in the tidal flats of the Midorikawa River.
The Changes in the Breeding Behaviour of the Microcarbo Pygmaeus, Nycticorax Nycticorax, Ardeola Ralloides Bubulcus Ibis, Egretta Garzetta Species on the South-Western Coast of the Caspian Sea
AN Taghiyev, NA Karimova, SV Badalova
Abstract: IN 2008-2023, the changes in breeding behavior of the migratory -nesting bird populations of I Microcarbo pygmaeus, Nycticorax nycticorax, Ardeola ralloides, Bubulcus ibis, Egretta garzetta on biotopes were studied on the South -Western coast of the Caspian Sea. Hundreds of thousands of bird populations from Africa and South -East Asian countries migrate to the Azerbaijani sector of the South -Western part of the Caspian Sea every year. Among the above -mentioned bird species only Bubulcus ibis has a migratory -nesting population in the Gizilaghaj Bay of the Caspian Sea. The rest of the species have migratory -nesting and sedentary populations. The number of migratorynesting populations in the study area is a hundred times more than that of sedentary populations. During this period, intra-species and inter -species competition intensifies in the struggle for nesting, feeding, roosting, resting, shelter and other living conditions between migratory -nesting and sedentary bird populations. The water level reduction and the related destruction of reeds and tamarisks, intraspecies and inter -species competition lead to changes in the breeding behaviour of migratory -breeding bird populations. As a result, the continuous, sustainable reproduction of these species becomes difficult, and the adoption of new nesting places by the species makes conservation problems more urgent.
Sub Hur , Dae-Woo Kim , Jong-Gil Park , Hae Rim Lee , Young-Jun Kim , Bae-Keun Lee , Dong-Ha Nam
Abstract: Three of the five global loon species commonly winter along the Korean coast, where they have increasingly been found dead or moribund. This study investigated hepatic elemental concentrations in 86 Arctic Loon (Gavia arctica), Pacific Loon (G. pacifica), and Red-throated Loon (G. stellata) carcasses collected from Korean coastal areas between 2010 and 2017 to assess the potential ecological impacts of elemental exposure. We analyzed 11 elements, focusing on toxic heavy metals and vanadium (V), which is a potential biomarker for hydrocarbon contamination. Hepatic concentrations of 10 elements showed no significant differences among causes of death, species, or geographic locations. Uranium was not detected in any samples. Notably, V accumulation patterns aligned with previous findings on polycyclic aromatic hydrocarbons (PAHs) in these birds, and weak, but significant correlation was observed between ∑16PAHs and V. This suggests that V from marine oil pollution may contribute to its accumulation in loons. The study found elevated levels of mercury and cadmium in all three loon species, but lead levels were not concerning. Temporal trend analysis over eight years showed no clear patterns in any examined element. Given the extensive breeding and migration routes of loons across Northeast Asia, North America, and Russia, this research underscores the importance of continuous ecotoxicological studies to address potential risks of environmental contamination for these migratory birds. Our findings contribute to understanding elemental exposure in wintering loons along the Korean coast and highlight the need for continued monitoring and international collaboration in migratory bird conservation efforts.
The influence of tidal action and reclamation activities on the home range selection of shorebirds
Cheng Wang , Hanwei Wang , ZhiHeng Shen , Guanqing Gong , Yong Zhou , Yu Xia , Wenxu Shen , Bin Wang
Abstract: The Tiaozini area is an important transit point for shorebirds on the East Asian – Australasian Flyway. The area has a long history of reclamation and development due to its unique marine landform and rich mudflat resources. However, the mechanisms of tidal and reclamation influences on shorebirds remain unclear. Therefore, this study used GPS data of four shorebirds in the Tiaozini area from 2018 to 2020, using the Dynamic Brownian Bridge Motion model to identify core home ranges. We applied the Normalized Difference Water Index (NDWI) and the Canny edge detection algorithm on 11 phases of Landsat-8 OLI and 17 phases of Sentinel-2 MSI remote sensing images to detect waterlines, simulating instantaneous waterlines based on multi-temporal data. Moran’s index was used to assess the impact of reclamation on shorebird home range selection. Results showed: (1) Home range selection of shorebirds varied interannually and seasonally, with total home range decreasing from 200.75 km2 to 193.67 km2 (2) Waterline fluctuations remained stable from 2018 to 2020, with intertidal zones decreasing from 55.46 % in 2018 to 38.66 % in 2020, and utilization rates of 18.92 % in spring and 45.80 % in autumn; (3) The bivariate Moran’s index between the intensity of reclamation and the probability of home range selection for each period was negative. The higher probability of shorebirds distribution was found in the eastern constructed wetlands, the central and eastern shallow water and reed marsh habitats. The areas with lower distribution probabilities concentrated in the industrial areas and urban residential areas in the southern part of the study area. This study provided a new perspective for exploring the mechanism of natural and human factors influencing home range selection at key nodes of important waterbird groups in migration routes and a reference for the conservation and restoration of waterbird habitats in World Heritage sites.
Haifeng Xu , Bin Dong , Zhili Xu , Jinji Ma , Fei Shen
Abstract: The Poyang Lake National Nature Reserve (PLNNR) is the most important reserve for wintering migratory birds in the Poyang Lake basin. The analysis of the spatial distribution of rare crane habitats and their response mechanisms to environmental variables is crucial for the conservation and restoration of both species and habitats. This study focuses on the rare crane species in the PLNNR, including Siberian Cranes (Grus leucogeranus), Hooded Cranes (Grus monacha), White-naped Cranes (Grus vipio) and Common Cranes (Grus grus). Based on occurrence data and environmental variables, the Maximum Entropy (Maxent) model was used to analyze the habitat suitability of the four crane species and to discuss their response mechanisms to key environmental variables. In addition, an ecological network was constructed for the four crane species using circuit theory and the Minimum Cumulative Resistance (MCR) model. The research results indicated that the highly suitable habitats for the four crane species were distributed along the edges of lake wetlands, with an area ranging from 63.97 to 128.21 km2, accounting for 15.31 to 30.69 %. The unsuitable areas were located in Wucheng town and along the waterways, with each area exceeding 25 %. Land use types, including reed beach, mudflat, waters, and cultivated land, were the main factors influencing crane habitat, with a contribution rate ranging from 15.9 to 36.3 %. In addition, the significant environmental variables varied among crane species. For the Siberian Crane, key factors included distance from grassland, aspect of slope, and distance from water. The Hooded Crane was primarily influenced by distance from water. The White-naped Crane was significantly affected by distance from grassland, cultivated land, and waterways. For the Common Crane, distance from water and construction land were the main influencing factors. Ecological networks were constructed for the four crane species and the PLNNR. The ecological network of the PLNNR consisted of 9 ecological sources, 13 ecological corridors, and 27 ecological nodes. Overall, the construction of the ecological network in the PLNNR was superior to that of individual crane species.
Migration and population characteristics of white-naped cranes wintering on the Korean Peninsula
Hyung-Kyu Nam, Hwa-Jung Kim, Batmunkh Davaasuren, Tseveenmyadag Natsagdorj, Nyambayar Batbayar, Jugdernamjil Nergui, Jin-Young Park, OtgonbayarTsend, Wee-Heang Hur, Dong-Won Kim* & Yu-Seong Choi
Abstract: The white-naped crane (Antigone vipio), distributed across East Asia, is classified into two distinct populations: eastern and western. The eastern population breeds in the Amur region of China and Russia and winters in Korea, whereas the western population breeds in northeastern Mongolia and winters at Poyang Lake in China. The aim of this study was to examine the population characteristics of white-naped cranes wintering in Korea and clarify the migratory behavior of the western population, which has been poorly understood. Population trends were assessed using data from the Winter Waterbird Census of Korea. In 2022 and 2023, the migratory routes were tracked using GPS transmitters attached to 12 cranes captured in eastern Mongolia. The analysis revealed a remarkable 2313.7% increase in the number of cranes wintering in Korea between 2000 and 2024 and demonstrated an expansion in their wintering range. The findings also confirmed that some individuals from the western population migrate to Poyang Lake and Korea. Systematic habitat management and improved wintering conditions on the Korean Peninsula could have been crucial factors in this increase. This study highlights the Korean Peninsula as a key wintering site for white-naped cranes in East Asia, providing valuable insights for future conservation strategies.
Shen Zhang , Xiaotong Ren , Ziyin Xiong , Tao He , Kar-Sin Katherine Leung , Wenjie Xue , Li Tian , Lifeng Zhuang , Yi-Chien Lai , Chia-Hsiang Lin , Chi-Yeung Choi
Abstract: Migratory shorebirds are experiencing rapid population decline. Monitoring programs along shorebird flyways provide information on their population dynamics and habitat requirements at different life stages, which is important for conservation plans. Such surveys often occur at several high-tide roosts during daytime high tide, when birds are more concentrated and easier to count. However, it remains unclear whether these surveys can cover the entire shorebird community within a site and represent shorebirds’ preferences during both day and night. Here, we tested two community-level hypotheses: 1) surveys at high-tide roosts can adequately represent the community within a site; and 2) daytime surveys can adequately represent birds’ preferences over the whole day, by combining GPS tracking data of four species – nine common redshanks (Tringa totanus), three grey plovers (Pluvialis squatarola), two greater sand plovers (Charadrius leschenaultii) and two red knots (Calidris canutus) – with community-level shorebird survey data in aquaculture ponds and nearby tidal flats on their overwintering grounds in southern China. Our results showed that in an area with extensive artificial roosting habitats, shorebirds using the same feeding area on the tidal flat may choose different roosts, even when alternative roosts are available nearby. Individuals within the three tracked species exhibited marked differences in roost selection between daytime and night, and the factors influencing roost selection varied both among species and between day and night. Therefore, daytime high-tide surveys alone are insufficient to assess habitat use and preferences at the species level. Management of shorebird roosting habitats should not assume uniform preferences across species.
2) 보전 & 관리
Zihan Zhang , Cheng Wang , Yonglian Qian , Qiuyue Zhang , Chaoran Song , Qingyu Li , Yutong Wu , Bin Dong
Abstract: The middle and lower reaches of the Yangtze River is an important stopover along the East Asian-Australasian Flyway. But this region is also a rapidly developing area in terms of economic level. The construction and simulation of the endangered species habitat network will be beneficial for future regional species habitat conservation and human activity management. The conservation and management also contribute to advancing the United Nations’ 2030 Sustainable Development Goals and the conservation of biodiversity hotspots. Therefore, based on crane habitats and environmental data in 2000∼2020, the study used circuit theory and PLUS model to construct (2000–2020) crane habitat networks and simulate (2030) land use data. Then, the study predicted the habitat networks in 2030. The results indicated that: (1) The sources from 2000 to 2020 were mainly distributed in Caizi Lake, Shengjin Lake, and Longgan Lake. From 2000 to 2020, the area of sources reduced from 103.48 km2 to 52.61 km2 which decreased by 49.16%. The number of corridors decreased by 48.15%. The total length of corridors decreased by 47.69%. The integrity of the habitat networks was weakened. (2) In 2030, the area of shoal increased by 0.77% in nature conservation scenario. In inertial development and urban expansion scenarios, construction land increased by 6.50% and 23.80%, respectively, mainly located in the northern area of Caizi Lake. (3) In nature conservation scenario, the number of sources increased from 7 to 10 relative to inertial development and urban expansion scenarios, and the number of corridors increased by 28.57% relative to 2020. The network closure index (α) in nature conservation scenario was 0.60 which was better than inertial development (0.56) and urban expansion (0.44) scenarios. Therefore, this study proposed sustainable optimization policies for sectional functional impairments of crane habitat networks based on the nature conservation scenario in 2030. It will provide an important reference for crane habitat conservation and wetlands structural restoration in the middle and lower reaches of the Yangtze River.
Xianglin Ji , Dingyong Zhang , Lizhi Zhou
Abstract: The natural hydrological rhythms of lakes play a crucial role in the aggregation of waterbirds. However, artificial controls of gate-controlled lakes alter water level fluctuations in the natural lakes and affect the diversity of waterbird communities. Wuchang Lake, a gated-controlled lake in the middle and lower Yangtze River floodplain, is an important wintering site for waterbirds on the East Asian–Australasian Flyway. Lake water level control during the wintering period in 2021–2022 was different than that in 2022–2023. We collected waterbird data from two wintering periods, based on functional alpha and beta diversity and waterbird functional groups, we analyzed the impact of water level regulation on wintering waterbird communities. By remote sensing data of foraging habitats we further analyzed the effects of changes in habitat structure to waterbird communities at different water levels. The results showed that during high lake water level, the numbers of deep water swimmers feeding on fish (G3) and swimmers feeding on seeds (G7) increased significantly, the number of large wading birds feeding on fish (G2) decreased significantly. And high lake water level decreased functional richness indices (FRic), functional evenness indices (FEve) and functional divergence indices (FDiv). Among them, in January and February 2023, the functional divergence indices significantly decreased. Functional beta diversity analysis showed that the total dissimilarity among communities decreased significantly in 2022–2023, with the functional nestedness component increasing significantly in October and February and the functional turnover component decreasing significantly in October, December, and February. Generalised linear mixed models (GLMM) showed that high lake level expanded the water area and favored the habitat of swimming birds, while decreased mudflat area, limiting the habitat space for wading birds. In contrast, lake water level decreased to increase the mudflat area and promoted the differences among communities. This study analysis a coupling relationship among water levels, habitats, and waterbirds, the results show that appropriate lake level regulation is an effective method to protect waterbirds. It provides scientific information for the lake wetland management and waterbird conservation.
Jia Guo , Waner Liang , Yan Zhou , Yifei Jia , Hongyan Yang , Lili Sun , Qing Chen , Ting Fu , Sicheng Ren , Wenkui Jiang , Guangchun Lei , Li Wen
Abstract: Land reclamation has significantly reduced tidal flats globally, leading to a sharp decline in shorebird populations and highlighting the urgent need for habitat restoration. Following reclamation, tidal flats are predominantly submerged during high tides, forcing shorebirds to seek roosts. To evaluate the effectiveness of various restoration and management methods on high-tide roosts, we studied shorebird utilization in Southern Jiangsu, China, a crucial staging site along the East Asian-Australasian Flyway. We conducted bird surveys during the autumn migration at six high-tide roosts: aquaculture pond using environmentally-friendly farming (EFF) (Site 1), restored and reserved roost (Site 2), unused reclaimed land (Site 3), unrestored flat (Site 4), restored flat (Site 5), and reclaimed farmland (Site 6). We used Bayesian generalized additive mixed effect models (GAMM) to analyze the effects of tide height and proportion of bare ground on shorebird density at the roost sites, and Permutational Multivariate Analysis of Variance (PERMANOVA) and nonmetric multidimensional scaling (NMDS) to compare community composition between roosts. Results showed that Sites 2 and 3 emerged as the most preferred roosting habitats. The model showed that shorebird density peaks when the proportion of bare ground is at 39 % in a roost. Our results showed that different management practices support different shorebird assemblages and highly variable abundance, with the relative proportion of bare ground, water and vegetation as critical factors in the extent to which shorebirds utilize high-tide roots. Continuous management is essential for the long-term success of restoration efforts, contributing to the understanding of sustainable practices in habitat restoration.
Short-term flooding in non-rice croplands provides stopover habitats for migrating waterbirds
Takehiko Shimizu , Masayuki Senzaki , Shunsuke Hori , Kota Sueda , Shintaro Ichihara , Ryugo Ishida , Jou Yoshigai
Abstract: Substantial areas of inland wetlands have been transformed into croplands globally. Although seasonal flooding in rice fields is well known to provide alternative habitats for species dependent on wetlands and aquatic environments, it remains unclear whether temporal flooding in other non-rice croplands, such as wheat fields, can serve a similar function. By focusing on the latest farming policy of short-term flooding on non-rice croplands in Japan, we investigated the diversity of a whole avian community and the major functional groups including waterbirds and globally declining migratory shorebirds in flooded croplands and conventional dry croplands from flooding to after-dried-out periods. We showed that species richness and abundance of waterbirds and shorebirds were significantly higher in the flooded croplands than in conventional dry croplands and dried-out croplands after flooding. The density of shorebirds in flooded non-rice fields was equivalent to that in the flooded rice fields in other regions. In contrast, terrestrial bird abundance and species richness were not significantly different between the land use types in both periods. Moreover, shorebird abundance and species richness decreased with the progressing season, which indicates their stopover habitat utilization might be highest at the peak of the migration. These results emphasize that short-term flooding even in non-rice fields is effective for serving artificial habitats to migrating waterbirds, potentially contributing to expanding waterbird conservation to broader regions and periods in which rice has not been growing.
Faid Rahman , Ahmad Ismail , Saiful Arif Abdullah , Aldrie Amir , Nuriah Abd Majid
Abstract: Birds are an excellent bio-indicator of biodiversity changes. Migratory shorebirds in particular cover a large distances traversing different types of habitats, from the tundra region in the most northern part of the world, to tropical and temperate areas in the southern most area. Kuala Gula, a sanctuary for more than 200 bird species is part of an Important Bird and Biodiversity Areas (IBAs) along the East-Asian Australian Flyway. Despite its importance, the area including its coastline is continuously pressured by anthropogenic activity. As such, there is a need to critically review Kuala Gula’s environmental status to highlight its potential, along with understanding the issues and threats particularly to the migratory shorebirds population in the long run. This is important not just to maintain Kuala Gula’s relevance as part of the important IBA in the Southeast Asia, but also to ascertain its qualification to meet its recognition’s goal. Throughout this review, we found that there are several issues that need to be addressed urgently, particularly ones related to pollution activity. Furthermore, the studies done so far are not coordinated well enough and lack continuity. As such, certain important information is still lacking making the protection and conservation of the area a big challenge. It is concluded that, the stability and sustainability of Kuala Gula’s habitats and its coastline is at stake, and there is a hope that this review will help related stakeholders to understand the current issues, and work together effectively to conserve the area.
Wenyi Tang, Jun Zhai
Abstract: Rivers are pivotal ecosystems for migratory waterbirds, with the habitat preferences of piscivorous species heavily influenced by hydrodynamic factors such as water depth and flow velocity. These variables directly impact food availability and the foraging behaviours of waterbirds. While the integration of hydrodynamic and habitat suitability models has been effective in assessing river conditions and guiding restoration efforts, research specific to instream-dependent piscivorous waterbirds at the reach scale is scarce. This research concentrates on the scaly-sided merganser (Mergus squamatus), an endangered species on the IUCN Red List, identifying crucial habitat factors—water depth, flow velocity and human disturbance distance—based on their significance in shaping wintering habitat choices for this bird. Through a coupled hydrodynamic habitat suitability model deployed in a segment of the Xitiaoxi River in southeastern China, the study seeks to create a tailored model for the scaly-sided merganser, assess distribution and landscape features of suitable instream habitats and suggest restoration and management tactics. Results show that despite the dry season revealing suitable areas for water depth (31.1%), flow velocity (16.8%) and human disturbance (80.5%) respectively, the combined suitable habitat only occupies 5.1%, predominantly in shallow regions like riffles and sandbanks. The study proposes strategies to enhance habitat suitability for the scaly-sided merganser, presenting a pragmatic approach for reach-scale river restoration, management and proactive conservation efforts beneficial for waterbirds. The findings are relevant not only for southern rivers in China but also for rivers in other countries that support migratory waterbirds and similar piscivorous waterbird habitats.
Spatially Diverse Water Levels Enhance Habitat Heterogeneity for Wintering Waterbirds
Zijian Wang, Jiaying Zhou, Ying He, Yangsirui Zhang, Peizhong Liu, Yifei Jia, Cai Lu, Guangchun Lei
Abstract: 1. Rising global temperatures and the increasing frequency of climate extremes pose significant challenges to waterbird conservation. These effects might be mitigated by managing habitat heterogeneity through diverse water levels in waterbird habitats. East Dongting Lake (EDL), a critical wintering site within the East Asian–Australasian Flyway, has experienced a significant drop in winter water levels due to extreme drought and operation of the Three Gorges Dam. This study aimed to determine optimal water levels for supporting waterbird populations under these changing conditions.
Qiu, Jingfeng; Li, Yu; Liu, Xinggen
Abstract: Poyang Lake, the largest freshwater lake of China, serves as a crucial wintering site for migratory birds in the East Asian–Australasian Flyway, where habitat quality is essential for maintaining diverse bird populations. Recently, the frequent alternation of extreme wet years, e.g., 2020, and dry years, e.g., 2022, have inflicted considerable perturbation on the local wetland ecology, severely impacting avian habitats. This study employed the spatiotemporal fusion method (ESTARFM) to obtain continuous imagery of Poyang Lake National Nature Reserve during the wintering seasons from 2020 to 2022. Habitat areas were identified based on wetland classification and water depth constraints. The results indicate that both extreme wet and dry conditions have exacerbated the fragmentation of migratory bird habitats. The shallow water habitats showed minor short-term fluctuations in response to water levels but were more significantly affected by long-term hydrological trends. These habitats exhibited considerable interannual variability across different hydrological years, affecting both their proportion within the overall habitat and their distribution within the study area. This study demonstrates the ability of ESTARFM to reveal the dynamic changes in migratory bird habitats and their responses to extreme hydrological conditions, highlighting the critical role of water depth in habitat analysis. The outcomes of this study improve the understanding of the impact of extreme water levels on migratory bird habitats, which may help expand knowledge about the protection of other floodplain wetlands around the world.
Study on Habitat Quality of Chongming Dongtan Based on InVEST Model in Shanghai, China
Jianshen Qu, Bin Dong, Xiao Liu & Zhili Xu
Abstract: Chongming Dongtan in Shanghai is one of the few remaining developing estuarine wetlands globally and serves as a crucial habitat along the Asia–Pacific migratory bird route. However, rapid economic and social development, coupled with direct and indirect human activities, has severely degraded the ecological environment of Chongming Dongtan. This study utilizes remote sensing images from 1996, 2002, 2008, 2014, and 2020 to construct a land use database for Chongming Dongtan. By integrating geographic information and data processing technologies, we analyze the land use changes in this region over time. Furthermore, we employ the InVEST model to investigate the changes in habitat quality over the past two decades. The results reveal that: (1) From 1996 to 2020, significant changes occurred in the land use types of Chongming Dongtan. Over 25 years, the areas of reed marshes, paddy fields, forest land, and construction land showed an overall increasing trend, while the area of Spartina alterniflora marshes decreased. Overall, in both 1996 and 2020, water bodies and Spartina alterniflora marshes were the largest and smallest land use types, respectively. (2) Analysis using the InVEST model indicates that the proportion of areas with poor habitat quality increased from 33.72% in 1996 to 41.62% in 2020, while the proportion of areas with excellent habitat quality decreased from 47.58% to 24.41% over the same period, demonstrating a general decline in habitat quality. (3) The drastic changes in land use and the increasing degree of landscape fragmentation in Chongming Dongtan have collectively led to changes in habitat quality. The study finds that regions experiencing significant ecological changes are closely linked to the expansion of construction land and Spartina alterniflora marshes. The increase in construction land has gradually deteriorated the internal habitat quality, while the external habitat quality has significantly changed with the growth and management of Spartina alterniflora marshes. This study can provide a reference for future decision-making in small-scale wetland ecological management.
Weipan Lei , José A. Masero , Ziwen Chai , Bing-Run Zhu , Tong Mu , He-Bo Peng , Zhengwang Zhang , Theunis Piersma
Abstract: The global expansion of human activities has led to a dramatic reduction in natural wetlands. While effectively managed artificial wetlands hold the potential to counteract this decline, there is often a lack of knowledge regarding how to enhance their value for wildlife. To bridge this gap, we studied one of the world’s largest saltworks in the Yellow Sea, China. This region has experienced significant natural wetland losses, resulting in marked declines in waterbird populations across the East Asian-Australasian Flyway (EAAF). Our research examined the impact of biotic factors such as prey abundance, and abiotic factors including water depth and management practices of saltpans, on the distribution of foraging shorebirds, as well as other waterbirds. Findings reveal that shorebirds, accounting for 95% of all waterbirds, heavily utilize saltpan evaporation ponds. Although various factors affect the distribution of shorebirds and other waterbirds, water depth and abandoned ponds (with low water depth) emerged as the primary factors. Notably, prey biomass (and abundance) did not exhibit a significant correlation with bird distribution across all shorebirds and other waterbirds, indicating that prey accessibility is more crucial than biomass in determining habitat suitability in these saltpans. Based on these insights, we propose tailored management strategies for the Yellow Sea saltpans that enhance conditions for shorebirds without impeding salt production, including lowering water levels through modifications to pond structures and reducing the volume of water evaporated during each stage of production. These straightforward, bird-friendly strategies provide practical solutions for adapting artificial wetlands to support migratory waterbirds in the EAAF and offer valuable insights for global waterbird conservation.
Feihong Yu , Jiancheng Zhai , Zhiqiang Huang , Jimei Chen , Fuqiang Han , Liaobo Wang
Abstract: Poyang Lake is one of the most typical seasonal inflow-outflow lakes in China. The cyclical rhythm of water level changes determines the dynamic variations in the wetland landscape pattern of Poyang Lake, directly impacting the habitat and survival of wintering migratory birds, particularly wading birds, which are most sensitive to these changes. This study employs an Artificial Neural Network (ANN) algorithm to interpret wetland landscapes using the Gao-Fen Satellite Images across 14 different water levels. Methods such as Pearson correlation and linear fitting are used to analyze the effects of water level changes on the habitat of wintering wading birds, aiming to explore scientifically based optimum water level. The ultimate goal is to provide a scientific basis for determining the optimum water level regulation scheme for the proposed Poyang Lake Hydraulic Project. The results indicate that the area and shape of Poyang Lake’s wetlands are highly plastic, with landscape heterogeneity decreasing and homogeneity increasing as water levels rise. The habitat area for wintering wading birds shows an inverted “V” shape variation with rising water levels, reaching a maximum of 1796.02 km² at a water level of 9.86 m, which accounts for about 48.40 % of the study area. The water level changes in Poyang Lake significantly impact the landscape pattern of the wading bird habitats (p < 0.01). When 6.83 ≤WL→WLx m, wading bird habitats become increasingly fragmented, with habitat patch type diversity, evenness, and connectivity gradually improving. When WLx→WL≤ 15.46 m, the degree of fragmentation moderates, but the diversity, evenness, and connectivity of habitat patches gradually decrease. At water levels between 8.15 and 13.56 m, the habitat structure for wintering wading birds is complex, with high diversity, large habitat area, and good landscape connectivity, providing favorable food acquisition resources and adequate space for wintering wading birds. Based on the need for wintering waterbird conservation, the proposed optimal optimum water level regulation threshold for the Poyang Lake Hydraulic Project is suggested to be between 8.15 and 13.56 m.
Taiyu Chen , Wei Hu , Dawei Wu , Changhu Lu*
Abstract: Introduction The coastal wetlands in eastern China are important feeding and resting sites for migratory waterbirds. Intertidal aquaculture in this region has various effects on waterbird communities, yet research on the impact of coastal restoration on waterbird communities remains limited.Methods To explore the impacts of coastal restoration in the Lianyungang coastal wetland, an important staging area for migratory birds along the East Asian-Australasian Flyway (EAAF), we conducted comparative studies on changes in waterbird community structure, behavior composition, and intertidal food resources before and after the removal of laver racks during autumn months from 2020 to 2023.Results The results were as follows: (1) A total of 11544 birds belonging to 37 species were recorded in the study area, including 8 globally threatened or near-threatened species. (2) Following restoration, species richness, abundance, Shannon-Wiener diversity index, and Margalef richness index of waterbirds were significantly higher compared to pre-restoration levels. Notably, the numbers of ducks, plovers, and sandpipers increased significantly, while gull numbers decreased significantly, likely due to habitat structure loss. (3) The proportion of foraging behaviors of 4 common waterbird species increased significantly after restoration, while the percentage of resting behavior significantly decreased. (4) No significant differences in macrobenthos species richness, abundance, biomass or alpha-diversity indices were detected post-restoration, but the macrobenthos in laver racks area (lower tidal zone) were significantly more abundant than those in the non-racks area (middle tidal zone).Discussion The laver farming racks not only occupied intertidal zones with abundant food resources but also limited the ability of some waterbird species to fly and evade predators, while the removal of these racks could restore foraging habitat accessibility by removing physical barriers. Our study revealed the trends in changes in waterbird communities before and after the removal of laver racks, providing practical insight and references for coastal restoration.
Estimating setback distances for a threatened, cryptic, data-sparse migratory shorebird
Hansen, Birgita D
Abstract: Cryptic fauna species using highly modified habitats face many conservation challenges, with disturbance from human use being an ongoing issue across many global settings. Setbacks or buffers are a key planning tool for protecting habitat, and are often specified under law. However, for many species using modified and urban habitats there are no published data on how wide setbacks should be. Latham’s Snipe (Gallinago hardwickii) is a case in point. It is a threatened, cryptic, migratory shorebird that breeds in Japan and spends its non-breeding season almost entirely in Australian wetlands and grasslands. Many sites used by snipe are within urban areas, potentially triggering protections under national law and there is an urgent need for information on setbacks to inform planning and conservation management. The aim of this project was to derive transparent, scientifically-derived buffer recommendations for mitigating disturbance to Latham’s Snipe, by estimating Alert Distances (AD; the first sign of behavioural disruption associated with human proximity) from measures of flush distances (FIDs; the distance at which flight occurs). ADs are almost impossible to observe in this cryptic species which uses dense habitat. We used 1529 FIDs to estimate AD from: (1) a within-species regression of FID against the few available ADs for this species (n = 8), and (2) cross-species associations between AD and FID of Scolopacidae from analysis of an unpublished dataset. FIDs varied between site and observers, so we resampled using bootstrapping to account for this variation and produce estimates of AD. Based on these estimates, we recommend minimum buffer widths between 75 – 110 m, which would prevent 80 – 95% of vigilance responses by Latham’s Snipe, respectively. The methods we employ may be useful in determining appropriate buffer widths for other cryptic fauna species. These buffers should be monitored for effectiveness and adapted as required.
Shu Zhang , Chao Sun , Jialin Li , Yongchao Liu , Xingru Shen , Chenwei Zhao
Abstract: The loss of coastal wetlands and the degradation of their ecological functions have posed a serious threat to the habitats of global migratory waterbirds, particularly the red-crowned cranes (Grus japonensis). Exploring dynamic changes in the habitat of this flagship species is essential for conserving waterbird diversity and improving wetland ecosystem functions. Therefore, using the Yancheng Biosphere Reserve (YBR)—the largest overwintering site for red-crowned cranes along the East Asian-Australasian Flyway—as a case study, we expanded beyond traditional habitat suitability assessments to include ecological networks, establishing a comprehensive evaluation framework. Specifically, we first enhanced the Habitat Suitability Index (HSI) by incorporating a fuzzy analytic hierarchy process based on the habitat preferences of red-crowned cranes. Ecological corridors were then extracted using the Minimum Cumulative Resistance (MCR) model and their importance was prioritized through a combination of gravity models and landscape connectivity indices. Additionally, circuit theory was employed to identify critical stepping stones and delineate key regions for protection. Our results demonstrated that the current ecological network exhibits poor stability and connectivity, characterized by the fragmentation and loss of ecological sources, degradation and breakup of ecological corridors, and increasing risks to stepping stones. Specifically, during 1991–2022, the total area of ecological sources significantly decreased from 1161.98 km2 to 221.81 km2, and the ecological sources in the southern YBR entirely loss after 2013. Optional low-importance, weak-connectivity corridors largely disappeared, while a few single high-importance, strong-connectivity corridors gradually emerged in their place, as a result of largely decreasing of key ecological corridors from 43 to 15. The proportion of stepping stones associated with natural wetlands decreased from 55.47 % to 38.37 %, accompanied by a reduction in area of the northern YBR. Based on the above analysis, we proposed three categories of conservation areas, aiming to bolster wetland conservation efforts and enhance waterbird biodiversity.
Yifei Jia , Lili Sun , Jia Guo , Sicheng Ren , Hongyan Yang , Geng Huang , Li Wen , Neil Saintilan , Qing Chen , Yuyu Wang , Guangchun Lei
Abstract: The Spoon-billed Sandpiper (Calidris pygmaea) is one of the world’s most critically endangered migratory shorebirds, facing severe threats along the East Asian-Australasian Flyway (EAAF). In recent years, many observations of this species were reported in new areas of southeast coasts in Asia, suggesting that there is large uncertainty in the current estimation of its nonbreeding habitats (i.e., staging and wintering grounds), presenting a knowledge gap for effective conservation. Using historical sightings collated from multiple sources, this study aimed to better understand the distribution of the shorebird’s suitable habitats by creating a random forest species distribution model utilizing landcover and topographic predictors. The predictions were then overlain with the current protection area network to identify gaps in conservation planning. Our results show that only 59 % of the suitable non-breeding habitats for Spoon-billed Sandpiper EAAF are located in the intertidal zone. Only 15 % of the predicted nonbreeding habitats are located within the current protection network. Moreover, we found that human disturbance pressure was high at both the protected and unprotected habitats. For suitable habitats outside protection areas, Thailand, Republic of Korea, and Bangladesh had highest human disturbance pressure. For suitable habitats within the current protection network, Democratic people’s Republic of Korea, Republic of Korea, and China had highest human disturbance pressure. Our results suggest that the staging sites along the Yellow Sea coasts and wintering grounds in the Thailand and Myanmar are the conservation priority areas, and management actions such as reducing human footprints in both protected and none-protected habitats, controlling the expansion of the invasive Spartina alterniflora, and maintaining tidal flats facing inundation by sea level rise are essential to sustain the population of this critically threatened shorebird.
3) 조류 인플루엔자 / 그 외
Novel H16N3 avian influenza viruses isolated from migratory gulls in China in 2023
Peng Peng , Jinyan Shen , Jinyan Shen , Wenjun Shi , Jing Guo , Mengjing Wang , Wenxi Li , Zhiqin Yue , Xiaohong Sun , Mengdi Guan , Lili Liu , Hongke Xu , Yujiao Xie , Anran Ren , Mingfeng Liu , Wenqiang Liu , Zhibin Zhang , Zhishu Xiao* , Xuyong Li*
Abstract: As a rare subtype of avian influenza virus, H16 viruses are predominant in gulls but rarely found in domestic birds. The low prevalence of H16 viruses has limited our understanding of their epidemiology and evolutionary dynamics. In this study, we isolated three novel H16N3 viruses from migratory gulls in East Asian–Australasian Flyway in eastern China in 2023, which are significantly different from previously identified isolates. To fully understand the epidemiology and genetics characteristics of the global H16 viruses, we compared the host divergence of several rare subtypes and determined that the H13 and H16 subtypes were predominantly pooled into different species of gulls by sharing their internal genes, whereas the waterfowl of Anatidae served as the primary natural reservoirs of the H8, H11, H12, H14, and H15 subtypes. Detailed phylogenetic analysis revealed the evolutionary divergence of globally circulating H16 viruses and their frequent gene reassortment. Furthermore, the gull origin H13 and H16 viruses collectively served as gene donors for the newly emerged highly pathogenic clade 2.3.4.4b H5N1 viruses because the H13/H16-like PA, NP, and NS genes have been introduced into circulating H5N1 viruses since May 2022 in Europe. To date, the H5N1 reassortants containing the H13/H16-like gene segments have been detected in wild and domestic birds and resulted in mammal and human infections. These results improve our knowledge of the ecology and genetics of H16 viruses and emphasize the need for surveillance to monitor the emergence of novel avian influenza viruses in migratory birds.
Weijie Chen , Shuiping Lu , Haiyan Xiong , Zhiyu Xiang , Yuxi Wang , Jingjing Hu , Yue Pan , Yanjiao Li , Qile Gao , Qi Chen , Siru Hu , Weibing Wang , Chenglong Xiong
Abstract: On January 30, 2024, China announced the first human case of H10N5 influenza infection. Prior to this, human cases of H10N7 and H10N8 had been reported. It is now appropriate to re-examine the evolution and future epidemiological trends of the H10 and N5 subtypes of avian influenza viruses (AIVs). In this study, we analyzed the reassortment characteristics of the first human-derived H10N5 AIV (A/Zhejiang/ZJU01/2023), as well as the evolutionary dynamics of the wild bird-derived H10 and N5 subtypes of AIVs over the past decade. Our findings indicate that the human-derived H10N5 AIV exhibited low pathogenicity. A/bean_goose/Korea/KNU-10/2022(H10N7) and A/mallard/Novosibirsk_region/962k/2018(H12N5) were identified as the potential reassortment parents. The virus has existed since 2022 and several isolations have been reported in Bangladesh. Phylogenetic analysis showed that H10Ny and HxN5 AIVs in China are clustered differently based on the East Asian-Australian (eastern) and Central Asian-Indian (western) migratory flyways. The H10Ny and HxN5 AIV reassortant strains may cause human infections through accidental spillover. It is possible that another center of AIV evolution, mutation, and reassortment may be developing along the migratory flyways in northeastern Asia, distinct from Europe, the Americas, and China’s Yangtze River Delta and Pearl River Delta, which should be closely monitored to ensure the safety of the public.
Takekawa, John Y; Chang-Yong, Choi; Prosser, Diann J; Sullivan, Jeffery D; Batbayar, Nyambayar; Xiao, Xiangming
Abstract: Wild waterfowl are considered to be the reservoir of avian influenza, but their distinct annual life cycle stages and their contribution to disease dynamics are not well understood. Studies of the highly pathogenic avian influenza (HPAI) virus have primarily focused on wintering grounds, where human and poultry densities are high year-round, compared with breeding grounds, where migratory waterfowl are more isolated. Few if any studies of avian influenza have focused on the molting stage where wild waterfowl congregate in a few selected wetlands and undergo the simultaneous molt of wing and tail feathers during a vulnerable flightless period. The molting stage may be one of the most important periods for the perpetuation of the disease in waterfowl, since during this stage, immunologically naïve young birds and adults freely intermix prior to the fall migration. Our study incorporated empirical data from virological field samplings and markings of Swan Geese (Anser cygnoides) on their breeding grounds in Mongolia in an integrated agent-based model (ABM) that included susceptible–exposed–infectious–recovered (SEIR) states. Our ABM results provided unique insights and indicated that individual movements between different molting wetlands and the transmission rate were the key predictors of HPAI perpetuation. While wetland extent was not a significant predictor of HPAI perpetuation, it had a large effect on the number of infections and associated death toll. Our results indicate that conserving undisturbed habitats for wild waterfowl during the molting stage of the breeding season could reduce the risk of HPAI transmission.
Zhifeng Peng , Chunyan Gao , Hongxing Qiao , Han Zhang , Huimin Huang , Yamin Sheng , Xiaojie Zhang , Baojun Li , Baoliang Chao , Jingjing Kang * and Chuanzhou Bian *
Abstract: Aeromonas veronii (A. veronii) is a ubiquitous bacterium in terrestrial and aquatic environments. It has a significant impact on animal and human health, with it becoming an emerging crucial pathogen worldwide. However, there have been no reports of mute swan infections. In the present study, after an observation of pathological changes, one bacterial strain isolated from a dead migratory mute swan was identified as A. veronii HNZZ-1/2022 based on its morphology, matrix-assisted laser desorption ionization–time of flight mass spectrometry (MALDI-TOF MS), and sequence analysis of the 16S rRNA and gyrB genes. To explore its pathogenicity, virulence gene detection and a gosling infection experiment were subsequently carried out, respectively. Six virulence genes for cytotonic enterotoxins (alt), lateral elastase (ela), lipase (lip), cytotoxic enterotoxin (act), aerolysin (aerA), and polar flagellin (fla) were present in the template DNA of A. veronii HNZZ-1/2022. Experimentally infected goslings exhibited hemorrhages of various different degrees in multiple organs. The half-maximal lethal dose (LD50) value of A. veronii strain HNZZ1/2022 was estimated to be 3.48 × 108 colony forming units (CFUs) per mL for goslings. An antimicrobial susceptibility test showed that the A. veronii HNZZ-1/2022 strain was resistant to meropenem, ampicillin, and enrofloxacin. To date, this is the first report of A. veronii in migratory mute swans, thus expanding the currently known host spectrum. These results suggest that the migratory mute swan is a new host for A. veronii and demonstrate the need for extensive surveillance and research of A. veronii to minimize its transmission between animals, the environment, and humans.
Saki Sakuma , Junki Mine , Yuko Uchida , Asuka Kumagai , Yoshihiro Takadate , Ryota Tsunekuni , Hayate Nishiura , Kohtaro Miyazawa
Abstract: Migratory water birds are considered to be carriers of high pathogenicity avian influenza viruses (HPAIVs). In Japan, mallards are often observed during winter, and HPAIV-infected mallards often shed viruses asymptomatically. In this study, we focused on mallards as potential carriers of HPAIVs and investigated whether individual wild mallards are repeatedly infected with HPAIVs and act as HPAIV carriers multiple times within a season. Mallards were experimentally infected with H5N1 and H5N8 HPAIVs that were isolated recently in Japan and phylogenetically belong to different hemagglutinin groups (G2a, G2b, and G2d). All of these strains are more infectious to mallards than to chickens, and the infected mallards shed enough virus to infect others, regardless of whether they exhibited clinical signs. Serum antibodies to the homologous antigen, induced by a single infection with a low virus dose (10 times the 50% mallard infectious dose), were maintained at detectable levels for 84 days. Immunity at 84 days post-inoculation fully protected the mallards from a challenge with the homologous strain, as demonstrated by a lack of viral shedding, and antibody levels did not increase significantly in most of these birds. Protection against heterologous challenge was also observed despite undetectable levels of antibodies to the challenge strain. Our findings suggest that repeated infections with homologous and heterologous HPAIV strains do not occur frequently in individual wild mallards within a season, particularly at low viral doses, and the frequency with which they act as carriers may be limited.
Jie Hu , Yuting Xu , Min Ma , Chenyao Zhao , Yue Yuan , Guimei He
Abstract: The H9N2 subtype of avian influenza virus poses significant challenges to global poultry and human health. During the active surveillance of avian influenza virus in wild birds in Shanghai from 2020 to 2023, a total of nine H9N2 viruses were identified. To better understand the genetic characteristics of these H9N2 viruses in Shanghai, the whole genome sequences were analyzed. Phylogenetical analysis showed that the nine H9N2 viruses have undergone complicated reassortment with waterfowl viruses along the East Asian-Australasian flyways. The nine H9N2 viruses were classified into seven genotypes, and some of them could contribute internal genes to recently circulating HPAI A(H5N8) and A(H5N1) viruses of clade 2.3.4.4b. These results highlight the importance of active surveillance of AIVs in wild birds to comprehend viral ecology and evaluate potential transmission risk in poultry and humans.
Zile Cheng , Yiwen Chen , Min Li , Chao Lv , Nan Zhou , Weiye Chen , JieWen Huang , QingTian Li , Zijing Gao , Xuesong Feng , Li Shi , YuFeng Yao , Xiaokui Guo , Yongzhang Zhu
Abstract: Migratory birds play a pivotal role in the global dissemination of antimicrobial resistance genes (ARGs), with shorebirds relying on coastal wetlands during their long-distance migrations, environments often contaminated and conducive to ARG transmission. However, systematic investigations into antimicrobial resistance (AMR) in shorebirds remain scarce. During spring and autumn of 2023, we collected 893 throat and cloacal swabs from 480 shorebirds, representing 28 species, at Chongming Dongtan, a critical stopover along the East Asian-Australasian Flyway. Our analysis identified six strains, including four extra-intestinal pathogenic E. coli (ExPEC) and two K. pneumoniae, that exhibited resistance to third-generation cephalosporins, with three ExPEC strains exhibiting significant virulence in Galleria mellonella infection assays. We identified two conjugative plasmids: E042113F_p1, carrying the blaCMY-2 gene in E. coli, and M50_p2, carrying the blaKPC-2 gene in a hypervirulent K. pneumoniae with a virulence plasmid harboring the aerobactin system. Bioinformatic and experimental analyses confirmed that these plasmids could transfer without any fitness cost, remaining stable for at least 30 passages. Surprisingly, genomic tracing revealed that among the plasmids similar to E042113F_p1 (blaCMY-2), the earliest was identified in a Chinese swallow in 2015, with subsequent detections in wild birds from Mongolia (2017), Russia (2018), and Australia (2019). Notably, these E04-CMY-like/M50-KPC-like plasmids predominantly originated from human sources, underscoring the pivotal role of human activity in the cross-species transmission of AMR. This human-mediated transmission of resistance elements into wildlife posed a substantial risk for amplifying and disseminating AMR through long-range migratory bird movements, highlighting the urgent need for international collaboration under a One Health framework. Integrated surveillance, environmental management, and stringent antibiotic stewardship are critical to mitigating the risks posed by migratory birds in amplifying and spreading AMR across ecosystems.
Yunbo Qiu , Chenlong Lv , Jinjin Chen , Yanqun Sun , Tian Tang , Yuanyuan Zhang , Yufeng Yang , Guolin Wang , Qiang Xu , Xiaoai Zhang , Feng Hong , Simon I. Hay , Liqun Fang , Wei Liu
Abstract: Background: Wild birds are significant vectors in global pathogen transmission, but the diversity and spatial distribution of the pathogens detected in them remain unclear. Understanding the transmission dynamics and hotspots of wild-bird-associated pathogens (WBAPs) is crucial for early disease prevention. Methods: We compiled an up-to-date dataset encompassing all WBAPs by conducting an extensive search of publications from 1959 to 2022, mapped their diversity and global distribution, and utilized three machine learning algorithms to predict geospatial hotspots where zoonotic and emerging WBAPs were prevalent. Findings: Based on 1,834 selected studies, a total of 760 pathogens associated with 1,438 wild bird species were identified, including 387 emerging and 212 zoonotic pathogens. Migratory birds exhibited higher pathogen richness (593 species) but a lower proportion of zoonotic pathogens (27.2%) compared to resident birds (303 species and 39.3%, both p < 0.01). When comparing different ecological groups, waterfowl had the highest richness of zoonotic pathogens (128 species), followed by songbirds (76 species). The distribution of WBAPs was significantly influenced by the habitat suitability index of wild birds, mammalian richness, and climatic factors. The potential geographical hotspots of zoonotic and emerging WBAPs were widely distributed in tropical areas of Asia, Africa, and South America, with zoonotic WBAPs having a wider distribution in South America. Conclusions: Our study illustrates that the geographical hotspots of WBAPs are more widespread than reported, especially in low-income areas, and that the identification, surveillance, and prevention of WBAP infections should be prioritized.
Highly Pathogenic Avian Influenza A(H5N1) Outbreak in Endangered Cranes, Izumi Plain, Japan, 2022–23
Mana Esaki, Kosuke Okuya, Kaori Tokorozaki, Yuko Haraguchi, Taichi Hasegawa and Makoto Ozawa
Abstract: During the 2022–23 winter season, >1,500 endangered cranes, including hooded cranes (Grus monacha) and white-naped cranes (Grus vipio), were found debilitated or dead in the Izumi Plain, Japan. Most of the cranes, particularly those collected in November, were infected with highly pathogenic avian influenza (HPAI) H5N1 viruses; virus shedding was higher from the trachea than from the cloaca. The isolation rate from the cranes’ roost water was not markedly higher than that of previous seasons, suggesting that the viruses might be more effectively transmitted among cranes via the respiratory route than through feces. Most wild bird–derived H5N1 isolates were phylogenetically distinct from viruses isolated on nearby chicken farms, indicating limited relationship between the wild bird and chicken isolates. Serologic analyses suggested that herd immunity had little effect on outbreak subsidence. This study deepens our understanding of the circumstances surrounding the unexpected HPAI outbreaks among these endangered cranes.
Subrata Barman, Jasmine C. M. Turner, M. Kamrul Hasan, Sharmin Akhtar, Trushar Jeevan, John Franks, David Walker, Nabanita Mukherjee, Patrick Seiler, Lisa Kercher, Pamela McKenzie, Robert G. Webster, Mohammed M. Feeroz & Richard J. Webby
Abstract: Avian influenza active surveillance was conducted in Bangladesh from January 2022 to November 2023 in live-poultry markets (LPMs) and Tanguar Haor wetlands. The predominant viruses circulating in LPMs were low pathogenic avian influenza (LPAI) A(H9N2) and clade 2.3.2.1a highly pathogenic avian influenza (HPAI) A(H5N1) viruses. Non-H9N2 LPAIs were found at Tanguar Haor and at a lower prevalence in LPMs. Starting from June 2023, we detected novel genotypes of clade 2.3.4.4b A(H5N1) viruses from ducks in LPMs. The HA, NA, and M genes of these viruses are related to those of 2020 European clade 2.3.4.4b H5N1 viruses such as A/Eurasian Wigeon/Netherlands/1/2020 (Netherlands/1). However, analyses of the other five gene segments’ sequences identified three distinct genotypes (BD-G2, BD-G3, and BD-G4). BD-G2 viruses were closely related to the clade 2.3.4.4b H5N1 viruses that have been detected in Japan and nearby regions since November 2022. BD-G3 viruses were reassortants, with gene segments from other Eurasian LPAI viruses. BD-G4 viruses were similar to BD-G2 viruses, but their NS gene was accrued from contemporary Bangladeshi clade 2.3.2.1a A(H5N1) viruses. The ability of any of the clade 2.3.4.4b viruses to displace the long-entrenched 2.3.2.1a A(H5N1) viruses in Bangladesh is unknown.
덩스옌(Deng Shiyan) 님께서 정리하셨습니다