The EAAFP Science Unit is highlighting some key journal publications in the flyway. The abstract of each journal article is placed following the literature list below.
1) Biology & ecology
- Behavioural plasticity and trophic niche shift: How wintering geese respond to habitat alteration
- Effects of migration and reproduction on the variation in persistent organic pollutant levels in Kentish Plovers from Cangzhou Wetland, China
2) Conservation & management
- Filling knowledge gaps in a threatened shorebird flyway through satellite tracking
- Loss of functional connectivity in migration networks induces population decline in migratory birds
- Where to draw the line? Using movement data to inform protected area design and conserve mobile species
- A network approach to prioritize conservation efforts for migratory birds
- Analyzing Stopover and Wintering Habitats of Hooded Cranes (Grus monacha): Implications for Conservation and Species Dispersion in the East Asia
3) Others
- Characterization of avian influenza H5N3 reassortants isolated from migratory waterfowl and domestic ducks in China from 2015 to 2018.
- New evidence for the east-west spread of the highly pathogenic avian influenza H5N1 virus between Central Asian and east Asian-Australasian flyways in China
1) Biology & ecology
Behavioural plasticity and trophic niche shift: How wintering geese respond to habitat alteration
Jialin Lei, Yifei Jia, Yuyu Wang, Guangchun Lei, Cai Lu, Neil Saintilan, Li Wen
Abstract：
The accelerated rate of human-induced environmental change poses a significant challenge for wildlife. The ability of wild animals to adapt to environmental changes has important consequences for their fitness, survival, and reproduction. Behavioural flexibility, an immediate adjustment of behaviour in response to environmental variability, may be particularly important for coping with anthropogenic change. The main aim of this study was to quantify the response of two wintering goose species (bean goose Anser fabalis and lesser white-fronted goose Anser erythropus) to poor habitat condition at population level by studying foraging behaviour. In addition, we tested whether behavioural plasticity could alter trophic niche. We characterised foraging behaviours and calculated daily home range (HR) of the geese using global positioning system tracking data. We calculated standard ellipse areas to quantify niche width using the delta C-13 and delta N-15 values of individual geese. We linked behavioural plasticity with habitat quality using ANCOVA (analysis of covariance) models. We also tested the correlation between standard ellipse areas and HR using ANCOVA model. We found significant differences in geese foraging behaviours between years in their daily foraging area, travel distance and speed, and turning angle. Specifically, the birds increased their foraging area to satisfy their daily energy intake requirement in response to poor habitat conditions. They flew more sinuously and travelled faster and longer distances on a daily basis. For the endangered lesser white-fronted goose, all behaviour variables were associated with habitat quality. For bean goose, only HR and turning angle were correlated with habitat quality. The birds, especially the lesser white-fronted goose, may have had a higher trophic position under poor conditions. Our findings indicate that wintering geese showed a high degree of behavioural plasticity. However, more active foraging behaviours under poor habitat condition did not lead to a broader trophic niche. Habitat availability could be responsible to the divergent responses of foraging HR and isotopic niche to human-induced environmental change. Therefore, maintaining natural hydrological regimes during the critical period (i.e. September-November) to ensure that quality food resources are available is central to the future of populations of geese within the East Asian-Australasian Flyway.
Wang, Dou; Zheng, Shucheng; Wang, Pu; Matsiko, Julius; Sun, Huizhong; Hao, Yanfen; Li, Yingming; Zhang, Zhengwang; Que, Pinjia; Meng, Derong; Zhang, Qinghua; Jiang, Guibin
Abstract:
Migratory Birds have been considered biovectors of persistent organic pollutants (POPs) from sources to remote areas. In the present study, Kentish Plovers (Charadrius alexandrines) were collected in different periods, including immigration, breeding and emigration, to investigate the effects of migration and reproduction on POP variations in this bird species. Significant differences were found for dichlorodiphenyltrichloroethane (DDT) and hexachlorobenzene (HCB) concentrations in muscles between the immigration and emigration periods (p < 0.01 and p < 0.001, respectively), which could be attributed to the higher pesticide residues in the wintering grounds of plovers. Female plovers could excrete about 20.8-42.7% of POP load into eggs. Nevertheless, the POP levels didn’t exhibit great reduction during the breeding period compared with other seasons, which suggested that the breeding status had little impact on POP levels in female plovers. The estimated mean transport masses of POPs driven by plover migration were at the milligram level (range: 0.02-7.05 mg), suggesting that the migration of plovers had limited impacts on the redistributions of POPs along their migratory routes.
2) Conservation & management
Filling knowledge gaps in a threatened shorebird flyway through satellite tracking
Ying‐Chi Chan, T. Lee Tibbitts, Tamar Lok, Chris J. Hassell, He‐Bo Peng, Zhijun Ma, Zhengwang Zhang, Theunis Piersma
Abstract：
Satellite‐based technologies that track individual animal movements enable the mapping of their spatial and temporal patterns of occurrence. This is particularly useful in poorly studied or remote regions where there is a need for the rapid gathering of relevant ecological knowledge to inform management actions. One such region is East Asia, where many intertidal habitats are being degraded at unprecedented rates and shorebird populations relying on these habitats show rapid declines.
We examine the utility of satellite tracking to accelerate the identification of coastal sites of conservation importance in the East Asian–Australasian Flyway. In 2015–2017, we used solar‐powered satellite transmitters to track the migration of 32 great knots (Calidris tenuirostris), an “Endangered” shorebird species widely distributed in the Flyway and fully dependent on intertidal habitats for foraging during the non‐breeding season.
From the great knot tracks, a total of 92 stopping sites along the Flyway were identified. Surprisingly, 63% of these sites were not known as important shorebird sites before our study; in fact, every one of the tracked individuals used sites that were previously unrecognized.
Site knowledge from on‐ground studies in the Flyway is most complete for the Yellow Sea and generally lacking for Southeast Asia, Southern China and Eastern Russia.
Synthesis and applications. Satellite tracking highlighted coastal habitats that are potentially important for shorebirds but lack ecological information and conservation recognition, such as those in Southern China and Southeast Asia. At the same time, the distributional data of tracked individuals can direct on‐ground surveys at the lesser known sites to collect information on bird numbers and habitat characteristics. To recognize and subsequently protect valuable coastal habitats, filling knowledge gaps by integrating bird tracking with ground‐based methods should be prioritized.
Loss of functional connectivity in migration networks induces population decline in migratory birds
Yanjie XU, Yali SI, Yingying, Yong ZHANG, Herbert H. T. PRINS, Lei CAO, Willem F. de BOER
Abstract：
Migratory birds rely on a habitat network along their migration routes by temporarily occupying stopover sites between breeding and non-breeding grounds. Removal or degradation of stopover sites in a network might impede movement and thereby reduce migration success and survival. The extent to which the breakdown of migration networks, due to changes in land use, impacts the population sizes of migratory birds is poorly understood. We measured the functional connectivity of migration networks of waterfowl species that migrate over the East Asian-Australasian Flyway from 1992 to 2015. We analysed the relationship between changes in non-breeding population sizes and changes in functional connectivity, while taking into account other commonly considered species traits, using a phylogenetic linear mixed model. We found that population sizes significantly declined with a reduction in the functional connectivity of migration networks; no other variables were important. We conclude that the current decrease in functional connectivity, due to habitat loss and degradation in migration networks, can negatively and crucially impact population sizes of migratory birds. Our findings provide new insights into the underlying mechanisms that affect population trends of migratory birds under environmental changes. Establishment of international agreements leading to the creation of systematic conservation networks associated with migratory species’ distributions and stopover sites may safeguard migratory bird populations.
Chi-Yeung Choi , He-Bo Peng, Peng He, Xiao-Tong Ren, Shen Zhang, Micha V. Jackson , Xiaojing Gan, Ying Chen, Yifei Jia, Maureen Christiek, Tony Flaherty, Kar-Sin Katherine Leung, Chenxing Yun, Nicholas J. Murray, Theunis Piersma, Richard A. Fuller, Zhijun Ma
Abstract：
Protected areas (PAs) are a cornerstone of modern conservation. For PM that are established to conserve mobile species, it is important to cover all the key areas regularly used by these species. However, zonation and boundaries of PM have often been established with limited knowledge of animal movements, leaving the effectiveness of some PM doubtful. We used radio tracking data to evaluate the extent to which two coastal PM in mainland China encompassed the full range of habitats used by migratory shorebirds during non-breeding seasons. The core zone (highest restriction on human activities) of the Yalu Jiang Estuary National Nature Reserve (Liaoning) incorporated only 22 +/- 6% (n = 34) of the diurnal home range (95% kernel density) of the endangered great knots Calidris tenuirostris. In contrast, the core zone of Chongming Dongtan (Shanghai) incorporated 73 +/- 24% (n = 25) of the home range of dunlins Calidris alpina. During high tide, great knots in Yalu Jiang mostly occurred in the experimental zone (least restriction on human activities) or sometimes outside the PA boundary altogether, where the birds could face substantial threats. By investigating satellite tracking records, consulting published literature, interviewing local experts and mapping habitat composition in different coastal PM in China, we found that wet artificial supratidal habitats were frequently used by migratory shorebirds but the coverage of these habitats in coastal PM was low. These PA boundaries and/or zonations should be revised to conserve mobile species more effectively. With the increasing number of tracking studies, analysing the spatial relationships between PM and the movement ranges of mobile species can increasingly inform the development of a representative, comprehensive PA network.
A network approach to prioritize conservation efforts for migratory birds
Xu, Yanjie; Si, Yali; Takekawa, John; Liu, Qiang ; Prins, Herbert H. T.; Yin, Shenglai; Prosser, Diann J.; Gong, Peng; de Boer, Willem F.
Abstract:
Habitat loss can trigger migration network collapse by isolating migratory bird breeding grounds from nonbreeding grounds. Theoretically, habitat loss can have vastly different impacts depending on the site’s importance within the migratory corridor. However, migration-network connectivity and the impacts of site loss are not completely understood. We used GPS tracking data on 4 bird species in the Asian flyways to construct migration networks and proposed a framework for assessing network connectivity for migratory species. We used a node-removal process to identify stopover sites with the highest impact on connectivity. In general, migration networks with fewer stopover sites were more vulnerable to habitat loss. Node removal in order from the highest to lowest degree of habitat loss yielded an increase of network resistance similar to random removal. In contrast, resistance increased more rapidly when removing nodes in order from the highest to lowest betweenness value (quantified by the number of shortest paths passing through the specific node). We quantified the risk of migration network collapse and identified crucial sites by first selecting sites with large contributions to network connectivity and then identifying which of those sites were likely to be removed from the network (i.e., sites with habitat loss). Among these crucial sites, 42% were not designated as protected areas. Setting priorities for site protection should account for a site’s position in the migration network, rather than only site-specific characteristics. Our framework for assessing migration-network connectivity enables site prioritization for conservation of migratory species.
Tianlong Cai, Falk Huettmann, Kisup Lee and Yumin Guo
Abstract:
The hooded crane (Grus monacha) is a vulnerable species. However, its stopover habitat receives little attention and is not well known or protected even. Here, we present the spatial distribution of the stopover habitats for hooded cranes in the East Asia. A machine learning modeling algorithm of maximum entropy (MaxEnt) was applied and evaluated with Stochastic Gradient Boosting and Random Forests based on 115 every year used occurrence points (1990-2013) and 14 environmental layers as predictors. Results show that the Songnen Plain and Korea Peninsula are the most important stopover habitats. Four other major areas are also suitable for stopover: (i) the coastal area of the Bohai Sea, (ii) the Three Rivers Plain-Amur River Basin, (iii) the Torey Lake Basin and the (iv) Zeya River-Heilongjiang River. The gap analysis revealed that existing nature reserves conserve merely 16.7% of the suitable habitat and 26.7% of the core habitat. However, much more suitable habitat is still located widely outside nature reserves. Based on our predictions, a total of 22 priority areas should be considered when developing new nature reserves or expanding the existing nature reserves. In addition, we suggest that seven regions located at the Korean Peninsula are also suitable for dispersing hooded cranes from Izumi, Japan. Artificial feeding, including setting up feeding stations with grain, artificial cranes (decoys) and artificial flowing water impoundments can be used to attract wintering hooded cranes at these seven sites. Theoretically, our models show that these habitats can accommodate approximately 3,713 wintering individuals (ca. 35% of the wintering population in Izumi).
3) Others
Li, Xuyong; Cui, Pengfei; Zeng, Xianying; Jiang, Yongping; Li, Yubao; Yang, Jiaxin; Pan, Yudi; Gao, Xinxin; Zhao, Conghui; Wang, Jinhui; Wang, Kai; Deng, Guohua; Guo, Jing
Abstract：
Wild and domestic aquatic birds are the natural reservoirs of avian influenza viruses (AIVs). All subtypes of AIVs, including 16 hemagglutinin (HA) and nine neuraminidase (NA), have been isolated from the waterfowls. The H5 viruses in wild birds display distinct biological differences from their highly pathogenic H5 counterparts. Here, we isolated seven H5N3 AIVs including three from wild birds and four from domestic ducks in China from 2015 to 2018. The isolation sites of all the seven viruses were located in the region of the East Asian‐Australasian Migratory Flyway. Phylogenetic analysis indicated that the surface genes of these viruses originated from the wild bird H5 HA subtype and the N3 Eurasian lineage. The internal genes of the seven H5N3 isolates are derived from the five gene donors isolated from the wild birds or ducks in Eastern‐Asia region. They were also divided into five genotypes according to their surface genes and internal gene combinations. Interestingly, two of the seven H5N3 viruses contributed their partial internal gene segments (PB1, M and NS) to the newly emerged H7N4 reassortants, which have caused first human H7N4 infection in China in 2018. Moreover, we found that the H5N3 virus used in this study react with the anti‐serum of the H5 subtype vaccine isolate (Re‐11 and Re‐12) and reacted well with the Re‐12 anti‐serum. Our findings suggest that worldwide intensive surveillance and the H5 vaccination (Re‐11 and Re‐12) in domestic ducks are needed to monitor the emergence of novel H5N3 reassortants in wild birds and domestic ducks and to prevent H5N3 viruses transmission from the apparently healthy wild birds and domestic ducks to chickens.
Weiyue Meng, Qiqi Yang, Bram Vrancken, Zhuo Chen, Dongping Liu, Lixia Chen, Xiang Zhao, Sarah François, Tian Ma, Ruyi Gao, Wendong Ru, Yunfeng Li, Hongxuan He, Guogang Zhang, Huaiyu Tian & Jun Lu
Abstract：
The spread of highly pathogenic avian influenza (HPAI) H5N1 virus is associated with wild fowl migration in East Asian-Australasian (EA) and Central Asian (CA) flyways. However, the spread of H5N1 virus between the two flyways is still unclear. Here, the movements of wild waterfowl were obtained from satellite tracking data covering seven bar-headed geese and three great black-headed gulls breeding in the Qinghai Lake area (along the EA flyway), and 20 whooper swans wintering in the Sanmenxia Reservoir area (at the CA flyway). From the 2688 samples that were screened from wild birds at Qinghai Lake after an outbreak of H5N1 in July 2015, four genomes of H5N1 virus were obtained from bar-headed geese. The results of phylogenetic analysis indicated that these H5N1 viruses belonged to clade 2.3.2.1c and their gene fragments were highly homologous with A/whooper swan/Henan/SMX1/2015 (H5N1) virus (ranging from 99.76% to 100.00%) isolated from a dead whooper swan from the Sanmenxia Reservoir area along the EA flyway in January 2015. Furthermore, the coincidental timing of the H5N1 outbreak with spring migration, together with phylogenetic evidence, provided new evidence of the east-to-west spread of HPAI H5N1 between the EA and CA migratory flyways of China.
