1) Biology & ecology
- Piersma, T., E. M. A. Kok, C. J. Hassell, H.-B. Peng, Y. I. Verkuil, G. Lei, J. Karagicheva, E. Rakhimberdiev, P. W. Howey, T. L. Tibbitts, and Y.-C. Chan. When a typical jumper skips: itineraries and staging habitats used by Red Knots (Calidris canutus piersmai) migrating between northwest Australia and the New Siberian Islands. Ibis
- Tian, H., D. Solovyeva, G. Danilov, S. Vartanyan, L. Wen, J. Lei, C. Lu, P. Bridgewater, G. Lei, and Q. Zeng. 2021. Combining modern tracking data and historical records improves understanding of the summer habitats of the Eastern Lesser White-fronted Goose Anser erythropus. Ecology and evolution 11:4126-4139.
- Zhang, P., Y. Zou, Y. Xie, S. Zhang, F. Zhu, X. Chen, F. Li, Z. Deng, Y. Yao, and Y. Song. 2021. Phenological mismatch caused by water regime change may explain the population variation of the vulnerable lesser white-fronted goose in east Dongting Lake, China. Ecological Indicators 127:107776.
- Galtbalt, B., A. Lilleyman, J. T. Coleman, C. Cheng, Z. Ma, D. I. Rogers, B. K. Woodworth, R. A. Fuller, S. T. Garnett, and M. Klaassen. 2021. Far eastern curlew and whimbrel prefer flying low – wind support and good visibility appear only secondary factors in determining migratory flight altitude. Movement Ecology 9:32.
- Rasool, M. A., M. A. Hassan, X. Zhang, Q. Zeng, Y. Jia, L. Wen, and G. Lei. 2021. Habitat Quality and Social Behavioral Association Network in a Wintering Waterbirds Community. Sustainability 13:6044.
- Che, X., M. Zhang, X. Zhao, Q. Zhang, Y. Zhao, A. P. Møller, and F. Zou. 2021. Long-term trends in the phylogenetic and functional diversity of Anatidae in South China coastal wetlands. Ecological Applications: e2344.
- Yang, L., W. Wang, P. Sun, S. Huang, R. Gao, D. Kong, W. Ru, T. Wronski, and G. Zhang. 2021. Extrinsic factors, endocrine mechanisms, and behavioral indicators of migratory restlessness in wintering whooper swans (Cygnus cygnus). Scientific Reports 11:12636.
- Zhang, Q., G. Zhang, X. Yu, Y. Liu, S. Xia, Z. Meng, and C. Xu. 2021. How do droppings of wintering waterbird accelerate decomposition of Carex cinerascens Kükenth litter in seasonal floodplain Ramsar Site? Wetlands Ecology and Management.
- Sun, X., W. Liu, S. Li, P. Chen, M. Cao, T. O. Randhir, and Y. Zhang. 2021. Species richness patterns of waterbirds overwintering on the Jiangsu coast for coastal reclamation. Ocean & Coastal Management 205:105488.
- Li, X., R. Cheng, W. Xiao, G. Sun, T. Ma, F. Liu, X. Liu, F. Qian, and K. Pan. 2021. Assessment of the Suitability of Wintering Anatidae Habitats before and after Impoundment in the Three Gorges Reservoir Region. Sustainability 13:4743.
- Wang, C., H. Liu, Y. Li, B. Dong, C. Qiu, J. Yang, Y. Zong, H. Chen, Y. Zhao, and Y. Zhang. 2021. Study on habitat suitability and environmental variable thresholds of rare waterbirds. Science of the Total Environment 785:147316.
- Qiu, X., H. Liu, X. Yin, and J. Qin. 2021. Combining the management of water level regimes and plant structures for waterbird habitat provision in wetlands. Hydrological Processes 35: e14122.
- Brandis, K. J., D. Mazumder, P. Gadd, B. Ji, R. T. Kingsford, and D. Ramp. Using feathers to map continental-scale movements of waterbirds and wetland importance. Conservation Letters: e12798.
- Fang, X., R. Wu, Y. Feng, Y. Huang, S. Liu, L. Yuan, J. Liu, X. Niu, X. Wang, and H. Hu. 2021. Enhancing bird diversity via species differential analysis at the Haizhu National Wetland Park in Guangzhou, China: a case study. Restoration Ecology 29: e13329.
- Martins, C. O., O. E. Olaniyi, and M. Zakaria. 2021. Environmental Factors and Spatial Heterogeneity Affect Occupancy Estimates of Waterbirds in Peninsular Malaysia. Ornithological Science 20:39-55, 17.
- Liang, J., Q. Meng, X. Li, Y. Yuan, Y. Peng, X. Li, S. Li, Z. Zhu, and M. Yan. 2021. The influence of hydrological variables, climatic variables and food availability on Anatidae in interconnected river-lake systems, the middle and lower reaches of the Yangtze River floodplain. Science of the Total Environment 768:144534.
2) Conservation & management
- Kim, J. H., S. Park, S. H. Kim, and E. J. Lee. 2021. Identifying high-priority conservation areas for endangered waterbirds using a flagship species in the Korean DMZ. Ecological Engineering 159:106080.
- Lei, W., Y. Wu, F. Wu, T. Piersma, Z. Zhang, and J. A. Masero. 2021. Artificial Wetlands as Breeding Habitats for Shorebirds: A Case Study on Pied Avocets in China’s Largest Saltpan Complex. Frontiers in Ecology and Evolution 9.
- Sung, Y.-H., C.-c. Pang, T. C.-h. Li, P. P. Y. Wong, and Y.-t. Yu. 2021. Ecological Correlates of 20-Year Population Trends of Wintering Waterbirds in Deep Bay, South China. Frontiers in Ecology and Evolution 9.
- Gong, M., S. Pang, Z. Gao, W. Wen, L. Zhang, G. Liu, H. Li, F. Qian, and W. Wang. 2021. The Path Forward: Conservation of Climate Change-Affected Breeding Habitat of Red-crowned Cranes near Zhalong Reserve, China. Pakistan Journal of Zoology 53:733-742.
- Debela, M. T., Q. Wu, Z. Li, X. Sun, O. Omeno, and Y. Li. 2021. Habitat Suitability Assessment of Wintering Herbivorous Anseriformes in Poyang Lake, China. Diversity 13:171.
- Zhu, Z., W. Huai, Z. Yang, D. Li, and Y. Wang. 2021. Assessing habitat suitability and habitat fragmentation for endangered Siberian cranes in Poyang Lake region, China. Ecological Indicators 125:107594.
- Yu, X., W. Zhu, J. Wei, S. Jia, A. Wang, Y. Huang, and Y. Zhao. 2021. Estimation of ecological water supplement for typical bird protection in the Yellow River Delta wetland. Ecological Indicators 127:107783.
- Wang, C., G. Wang, L. Dai, H. Liu, Y. Li, C. Qiu, Y. Zhou, H. Chen, B. Dong, Y. Zhao, and Y. Zhang. 2021. Study on the effect of habitat function change on waterbird diversity and guilds in Yancheng coastal wetlands based on structure–function coupling. Ecological Indicators 122:107223.
- Fan, J., X. Wang, W. Wu, W. Chen, Q. Ma, and Z. Ma. 2021. Function of restored wetlands for waterbird conservation in the Yellow Sea coast. Science of the Total Environment 756:144061.
3) Avian Influenza /Others
- Wen, F., J. Yang, J. Guo, C. Wang, Q. Cheng, Z. Tang, K. Luo, S. Yuan, S. Huang, and Y. Li. 2021. Genetic characterization of an H5N6 avian influenza virus with multiple origins from a chicken in southern China, October 2019. BMC Vet Res 17:200.
- Hoye, B. J., C. M. Donato, S. Lisovski, Y. M. Deng, S. Warner, A. C. Hurt, M. Klaassen, and D. Vijaykrishna. 2021. Reassortment and Persistence of Influenza A Viruses from Diverse Geographic Origins within Australian Wild Birds: Evidence from a Small, Isolated Population of Ruddy Turnstones. Journal of Virology 95.
- Man, Y. B., K. L. Chow, F. Zhang, K. M. Lei, A. O. W. Leung, W. Y. Mo, and M. H. Wong. 2021. Protecting water birds of wetlands: Using toxicological tests and ecological risk assessment, based on metal/loid (s) of water, sediment and biota samples. Science of the Total Environment 778:146317.
- Nakao, M., and M. Sasaki. 2021. Trematode diversity in freshwater snails from a stopover point for migratory waterfowls in Hokkaido, Japan: An assessment by molecular phylogenetic and population genetic analyses. Parasitology International 83:102329.
- Zhang, N., L. Zhou, Z. Yang, and J. Gu. 2021. Effects of Food Changes on Intestinal Bacterial Diversity of Wintering Hooded Cranes (Grus monacha). Animals : 11:433.
- Yang, Z., and L. Zhou. 2021. Is Intestinal Bacterial Diversity Enhanced by Trans-Species Spread in the Mixed-Species Flock of Hooded Crane (Grus monacha) and Bean Goose (Anser fabalis) Wintering in the Lower and Middle Yangtze River Floodplain? Animals 11:233.
1) Biology & ecology
Theunis Piersma, Eva M. A. Kok, Chris J. Hassell, He-Bo Peng, Yvonne I. Verkuil, Guangchun Lei, Julia Karagicheva, Eldar Rakhimberdiev, Paul W. Howey, T. Lee Tibbitts, Ying-Chi Chan
Abstract: The ecological reasons for variation in avian migration, with some populations migrating across thousands of kilometres between breeding and non-breeding areas with one or few refuelling stops, in contrast to others that stop more often, remain to be pinned down. Red Knots Calidris canutus are a textbook example of a shorebird species that makes long migrations with only a few stops. Recognizing that such behaviours are not necessarily species-specific but determined by ecological context, we here provide a description of the migrations of a relatively recently described subspecies (piersmai). Based on data from tagging of Red Knots on the terminal non-breeding grounds in northwest Australia with 4.5- and 2.5-g solar-powered Platform Terminal Transmitters (PTTs) and 1.0-g geolocators, we obtained information on 19 route-records of 17 individuals, resulting in seven complete return migrations. We confirm published evidence that Red Knots of the piersmai subspecies migrate from NW Australia and breed on the New Siberian Islands in the Russian Arctic and that they stage along the coasts of southeastern Asia, especially in the northern Yellow Sea in China. Red Knots arrived on the tundra breeding grounds from 8 June onwards. Southward departures mainly occurred in the last week of July and the first week of August. We documented six non-stop flights of over c. 5000 km (with a maximum of 6500 km, lasting 6.6 days). Nevertheless, rather than staging at a single location for multiple weeks halfway during migration, piersmai-knots made several stops of up to a week. This was especially evident during northward migration, when birds often stopped along the way in southeast Asia and ‘hugged’ the coast of China, thus flying an additional 1000-1500 km compared with the shortest possible (great circle route) flights between NW Australia and the Yellow Sea. The birds staged longest in areas in northern China, along the shores of Bohai Bay and upper Liaodong Bay, where the bivalve Potamocorbula laevis, known as a particularly suitable food for Red Knots, was present. The use of multiple food-rich stopping sites during northward migration by piersmai is atypical among subspecies of Red Knots. Although piersmai apparently has the benefit of multiple suitable stopping areas along the flyway, it is a subspecies in decline and their mortality away from the NW Australian non-breeding grounds has been elevated.
Haitao Tian, Diana Solovyeva, Gleb Danilov, Sergey Vartanyan, Li Wen, Jialin Lei, Cai Lu, Peter Bridgewater, Guangchun Lei, Qing Zeng
Abstract: The Lesser White-fronted Goose (Anser erythropus), smallest of the “gray” geese, is listed as Vulnerable on the IUCN Red List and protected in all range states. There are three populations, with the least studied being the Eastern population, shared between Russia and China. The extreme remoteness of breeding enclaves makes them largely inaccessible to researchers. As a substitute for visitation, remotely tracking birds from wintering grounds allows exploration of their summer range. Over a period of three years, and using highly accurate GPS tracking devices, eleven individuals of A. erythropus were tracked from the key wintering site of China, to summering, and staging sites in northeastern Russia. Data obtained from that tracking, bolstered by ground survey and literature records, were used to model the summer distribution of A. erythropus. Although earlier literature describes a patchy summer range, the model suggests a contiguous summer habitat range is possible, although observations to date cannot confirm A. erythropus is present throughout the modeled range. The most suitable habitats are located along the coasts of the Laptev Sea, primarily the Lena Delta, in the Yana-Kolyma Lowland, and smaller lowlands of Chukotka with narrow riparian extensions upstream along major rivers such as the Lena, Indigirka, and Kolyma. The probability of A. erythropus presence is related to areas with altitude less than 500 m with abundant wetlands, especially riparian habitat, and a climate with precipitation of the warmest quarter around 55 mm and mean temperature around 14 degrees C during June-August. Human disturbance also affects site suitability, with a gradual decrease in species presence starting around 160 km from human settlements. Remote tracking of animal species can bridge the knowledge gap required for robust estimation of species distribution patterns in remote areas. Better knowledge of species’ distribution is important in understanding the large-scale ecological consequences of rapid global change and establishing conservation management strategies.
Pingyang Zhang, Yeai Zou, Yonghong Xie, Siqi Zhang, Feng Zhu Xinsheng Chen, Feng Li, Zheng miao Deng, Yi Yao, Yucheng Song
Abstract: Phenological mismatches between migratory birds and food availability driven by global warming have been found to influence the fitness and population dynamics of several herbivorous goose species in Arctic breeding sites. However, the effect of phenological mismatches at wintering sites have been inadequately studied. We used long-term data to explore the consequences of water regime changes on phenological mismatch (i.e., days between arrival of geese and timing of the optimal Normalized Difference Vegetation Index [NDVIopt]) and detect the relative role of the mismatch as a driver of annual variations in abundance and distribution of the Lesser White-fronted Goose Anser erythropus (a vulnerable species on the IUCN Red List) in East Dongting Lake, which is the one of this species’ largest wintering sites worldwide. The NDVI of the Carex meadow (i.e., the dominant vegetation in East Dongting Lake wetland and also the major food resource for the geese) was used as the phenology metric. Results showed that the water recession pattern greatly influenced food conditions when geese arrived at the site. Early water recession led to significantly higher NDVI, whereas late water recession led to significantly lower NDVI than did the optimal water recession. However, the suitable habitat area was significantly larger under the optimal water recession pattern. Both early and late water level recessions caused greater mismatches and resulted in lower geese abundance and a more concentrated distribution. NDVI was positively correlated with aboveground biomass and negatively correlated with N% of Carex spp. High biomass and low N% related to high NDVI caused by early water recession may indicate unfavorable food conditions at the time that geese arrive and reduced sustainable food availability in mid-winter, while a low NDVI and limited habitat area caused by late water recession may indicate an insufficient food supply. In conclusion, non-optimal water recession led to a greater phenological mismatch and resulted in limited habitat quality (e.g., lower leaf N%) under early water recession but limited habitat quantity (e.g., smaller habitat area and lower aboveground biomass) under late water recession, and ultimately threatened the Lesser White-fronted Goose. Our results contributed to explaining the decline of the Lesser White-fronted Goose population in this wintering site.
Batbayar Galtbalt, Amanda Lilleyman, Jonathan T. Coleman, Chuyu Cheng, Zhijun Ma, Danny I. Rogers, Bradley K. Woodworth, Richard A. Fuller, Stephen T. Garnett & Marcel Klaassen
Abstract: Background In-flight conditions are hypothesized to influence the timing and success of long-distance migration. Wind assistance and thermal uplift are thought to reduce the energetic costs of flight, humidity, air pressure and temperature may affect the migrants’ water balance, and clouds may impede navigation. Recent advances in animal-borne long-distance tracking enable evaluating the importance of these factors in determining animals’ flight altitude. Methods Here we determine the effects of wind, humidity, temperature, cloud cover, and altitude (as proxy for climbing costs and air pressure) on flight altitude selection of two long-distance migratory shorebirds, far eastern curlew (Numenius madagascariensis) and whimbrel (Numenius phaeopus). To reveal the predominant drivers of flight altitude selection during migration we compared the atmospheric conditions at the altitude the birds were found flying with conditions elsewhere in the air column using conditional logistic mixed effect models. Results Our results demonstrate that despite occasional high-altitude migrations (up to 5550 m above ground level), our study species typically forego flying at high altitudes, limiting climbing costs and potentially alleviating water loss and facilitating navigation. While mainly preferring migrating at low altitude, notably in combination with low air temperature, the birds also preferred flying with wind support to likely reduce flight costs. They avoided clouds, perhaps to help navigation or to reduce the risks from adverse weather. Conclusions We conclude that the primary determinant of avian migrant’s flight altitude selection is a preference for low altitude, with wind support as an important secondary factor. Our approach and findings can assist in predicting climate change effects on migration and in mitigating bird strikes with air traffic, wind farms, power lines, and other human-made structures.
Habitat Quality and Social Behavioral Association Network in a Wintering Waterbirds Community
Muhammad Awais Rasool, Muhammad Azher Hassan, Xiaobo Zhang, Qing Zeng, Yifei Jia, Li Wen and Guangchun Lei
Abstract: Migratory waterbirds concentrated in freshwater ecosystems in mosaic environments rely on quality habitats for overwintering. At West Dongting Lake National Nature Reserve (WDLNNR), China, land-use change and hydrology alternation are compounding factors that have affected important wintering areas for migratory waterbirds. Presently, changes in the hydrology and landscape have reshaped natural wintering habitats and their availability, though the impact of hydrological management on habitat selection of wintering waterbirds is largely unknown. In this study, we classified differentially managed habitats and calculated their area using the normalized difference vegetation index (NDVI) to evaluate suitable habitat availability over the study period (2016-2017 and 2017-2018 wintering periods). We then used social behavioral association network (SBAN) model to compare habitat quality through species-species social interactions and species-habitat associations in lakes with different hydrological management. The results indicated that social interactions between and within species structured wintering waterbirds communities, which could be dominated by one or more species, while dominant species control the activities of other co-existing species. Analysis of variance (ANOVA) tests indicated significant differences in SBAN metrics between lakes (p = 0.0237) and habitat (p < 0.0001) levels. Specifically, lakes with managed hydrology were preferred by more species. The managed lakes had better habitat quality in terms of significantly higher habitat areas (p < 0.0001) and lower habitat transitions (p = 0.0113). Collectively, our findings suggest that proper hydrological management can provide continuous availability of quality habitats, especially mudflats and shallow waters, for a stable SBAN to ensure a wintering waterbirds community with more sympatric species in a dynamic environment.
Xianli Che, Min Zhang, Xuebing Zhao, Qiang Zhang, Yanyan Zhao, Anders Pape Møller, Fasheng Zou
Abstract: Species loss has attracted much attention among scientists for more than half a century. However, we have little information on the trends in phylogenetic and functional changes behind the species loss although this information is always asynchronous and important for conservation and management. We measured community trends in Anatidae (ducks and geese) for the last 50 yr to quantify trends in phylogenetic and functional diversity patterns coinciding with taxonomic historical dynamics. We used one-way ANOVAs to test if there was a significant historical trend in communities of Anatidae. We characterized taxonomic, phylogenetic, and functional diversity of communities. For taxonomic diversity, we used species richness (SR). For phylogenetic diversity, we calculated the standardized effect size of mean pairwise distances (ses.MPD) and the standard effect size of mean nearest taxon distances (ses.MNTD) in communities. For functional diversity, we calculated functional richness (FRic), functional evenness (FEve), functional divergence (FDiv), and the community-level weighted means (CWM) of trait values for diet, foraging stratum, and body mass, separately. From the 1950s to 2010s, species richness declined without significant trends. The ses.MNTD of Anatidae communities showed no clear trends. However, ses.MPD of Anatidae communities declined dramatically during this period. For functional diversity, functional evenness of diet, foraging stratum, body mass, and functional dispersion of diet, foraging stratum did not increase or decline significantly. However, functional evenness of all traits, functional richness, and functional dispersion of body mass showed declined trends. The basic phylogenetic diversity and species body mass of Anatidae communities declined significantly because of a declining trend in the relative independent branch of geese. This makes it more challenging for implement community recovery in the future. More attention in conservation biology should consider taxonomic diversity and asynchrony in phylogenetic and functional diversity.
Liangliang Yang, Wenxia Wang, Ping Sun, Songlin Huang, Ruyi Gao, Desheng Kong, Wendong Ru, Torsten Wronski & Guogang Zhang
Abstract: Extrinsic factors, endocrine mechanisms, and behavioral indicators of migratory restlessness were studied in wintering whooper swans (Cygnus cygnus) in the Sanmenxia Swan National Wetland Park in western Henan Province, central China. First, the fecal glucocorticoid metabolite (FGM) concentration was established and related to mean air temperature or photo period (day length) using simple linear or non-linear regression models. After a model selection procedure, the best fitted model revealed that an increase of FGM concentration was associated with an increase in the squared mean air temperature (R2=0.88). Other models showed an increasing FGM concentration to correspond with increasing values of day length, squared day length, and mean air temperature-however without statistical support. In a second step, behavioral frequencies of seven behaviors were condensed into three behavioral principal components (PCs) using principal components analysis. Behavioral PCs largely corresponded to three activity phases described for wintering whooper swans in central China and were correlated with the FGM concentration using Spearman’s rank-order correlations. Results revealed a significant correlation between FGM and behavioral PC2 (positive factor loadings from vigilance and preening, negative loading from foraging). Finally, we tested for an effect of behavioral PCs on changes in winter home range size using a set of multiple linear regression models. Results of averaged model parameter estimates showed only the behavioral PC3 (positive factor loadings from fighting and calling, negative loading from locomotion) had a marginal significant effect on home range size. Results confirmed findings of previous studies on migratory restlessness in whooper swans. However, due to the small sample size (N=15weeks) the effect of PC3 on home range size was weak and should be viewed with caution.
Quanjun Zhang, Guangshuai Zhang, Xiubo Yu, Yu Liu, Shaoxia Xia, Zhujian Meng & Ce Xu
Abstract: The decomposition of wetland plant litter is pivotal in the functioning of wetland ecosystems in terms of organic matter mineralization progress and nutrient cycling. Aiming to investigate the effects of the droppings of wintering herbivorous waterbirds on the decomposition of Carex cinerascens Kukenth litter a newly designated Ramsar Site, decomposition patterns of three types of samples were characterized and compared by waterbird dropping addition and litterbag in situ experiment. The three types of samples are OCL (only C. cinerascens litter), OWD (only waterbird droppings) and CMD (C. cinerascens litter mixed with waterbird droppings), respectively. A total of 105 decomposition bags were placed and the experiment lasted 150 days. The results showed that the average decay rate of C. cinerascens cellulose increased by approximately 32.12% by the addition of bird droppings, while the C. cinerascens lignin decay rate increased by approximately 83.05%. And the release of carbon, nitrogen and phosphorous of C. cinerascens increased by approximately 18.3%, 61.09%, and 66.71%, respectively. We concluded that the addition of waterbird droppings significantly accelerated the decomposition of C. cinerascens litter and the release of carbon, nitrogen, and phosphorus. We have a preliminary deduction that waterbird droppings (1) altered the original stoichiometric ratio of the litter, (2) increased the available nutrient content, (3) increased the colonization ability of the microorganisms, and (4) stimulated the production of a series of extracellular degradation enzymes. This study provides a thinking that the important role of waterbirds should be given full attention in wetland restoration planning and management.
Species richness patterns of waterbirds overwintering on the Jiangsu coast for coastal reclamation
Xiaoping Sun, Wei Liu, Shuang Li, Peng Chen, Mingchang Cao, Timothy O.Randhir, Yinlong Zhang
Abstract: It is vital to identify factors that affect the overwintering of waterbirds for conservation purposes. In this study, during the winter of 2018?2019, we documented 177,414 individuals of 74 species of waterbirds in the Jiangsu coastal area, an important but poorly known overwintering location. Of the species observed, 12 were listed as threatened. We found that natural wetlands loss is a significant contributor to population declines among overwintering waterbird species in the Jiangsu coastal area, greater than anthropogenic disturbance. This loss has forced waterbirds to choose artificial wetlands, where a total of 47 species were detected. Sorted by key zones for overwintering waterbirds, 16 surveying zones were identified in the area, and most are not fully protected. Thus, conservation efforts aimed at waterbirds should focus on at least 12 conservation gaps in diversity hotspots, emphasizing the management of artificial wetlands in the Jiangsu coastal area.
Xiuming Li, Ruimei Cheng, Wenfa Xiao, Ge Sun, Tian Ma, Fuguo Liu, Xiaoyun Liu, Fawen Qian and Kaijun Pan
Abstract: In this study, we aimed to understand the distribution of and changes in the habitats suitable for Anatidae wintering in the Three Gorges Reservoir Region (TGRR), China, and to explore the impact of the impoundment during different impoundment periods. Based on species occurrence data for four dominant species of Anatidae and environmental factors, a maximum entropy (MaxEnt) model was used to analyze the suitability of habitats during five impoundment periods. The results show that the main factors affecting Anatidae distribution were temperature and roads before the Three Gorges Project (TGP) and elevation after the TGP. After the TGP, the area of the suitable habitat declined rapidly and then gradually increased with increasing water level. After impoundment, the primary area of increased habitat suitability was the main stream of the Yangtze River from Changshou District to Yunyang County and its tributary in the Kaizhou area. Among the habitats, the central water regions were more suitable than the marginal shoal areas. Anatidae habitats in the TGRR were distributed mainly within the Yangtze River main stream and the surrounding areas before the TGP, and the surrounding areas largely disappeared after the TGP, particularly in Chongqing City and Jiangjin District. In this context, it is challenging to create new protected areas within the habitat suitable for Anatidae in the main stream of the Yangtze River; we propose adding the Anatidae as conservation targets within the existing conservation agencies and implementing a waterbird monitoring program for scientific waterbird conservation and the sustainable development of the reservoir.
Study on habitat suitability and environmental variable thresholds of rare waterbirds
Cheng Wang, Hongyu Liu, Yufeng Li, Bin Dong, Chunqi Qiu, Jialing Yang, Ying Zong, Hao Chen, Yongqiang Zhao, Yanan Zhang
Abstract: The conservation level of rare waterbirds reflects the quality of the regional ecological environment and wetlands, and suitable habitat patches and good environmental conditions are bases to support the activities of rare species in habitats. Establishing these conditions is also an important goal of habitat landscape and functional restoration. However, lack of these conditions limits population protection and habitat restoration of rare species. Based on the random forest (RF) algorithm and threshold indicator taxa analysis (TITAN), this paper performed habitat suitability assessment and environmental variable threshold analysis of rare waterbird species in Yancheng coastal wetlands. The results showed that the suitable area proportion of three waterbird species at different habitat sites was less than 20%. The unsuitable area proportions of red-crowned cranes and oriental storks at the CA habitat site were the highest, reaching 86.73% and 85.17%, respectively. In addition, analysis of the importance of environmental variables showed that the main influencing variables affecting the suitable habitat distribution of the three rare waterbirds were habitat type (T_hab), habitat area (A_hab), vegetation coverage (P_fvc), distance to farmland (D_far), distance to reeds (D_ree), ponds density (Ponds), distance to water surface (D_wat) and distance to main roads or seawalls (D_swa). These variables covered the type, area, coverage and distance indicators. With the exception of D_far, Ponds and D_swa, rare waterbirds had response thresholds to each environmental indicator, and these results supported the restoration of landscape structure and function of each habitat site. This study emphasized the importance of foods, water resources and hidden conditions for habitat selection in rare waterbirds. Finally, we proposed the maintenance and restoration patterns of the landscape structure and function of rare waterbird habitats, which are available for other coastal tidal wetlands.
Xintian Qiu, Hongrui Liu, Xinan Yin, Jinglan Qin
Abstract: The survival of waterbirds depends heavily on habitat, particularly aquatic plants. For each kind of aquatic plant, there are specific water level regime requirements to meet its germination and growth. Previous studies usually focused on the use of water level management to achieve protection and restoration of aquatic plants. However, the water level regimes in many wetlands have been greatly changed and their ecological objectives usually cannot be achieved by water level management alone. Accordingly, this study combined water level management and artificial planting for waterbird habitat provision in wetlands. The Hongze Lake National Wetland Nature Reserve was taken as the research area. In this study, we considered the needs of waterbirds for nesting and foraging, and determined the aquatic plant species to be planted. According to the seasonal water level requirements of these plants, we simulated the plantable areas of different aquatic plants under different water level regimes. We then further optimized the water level regimes according to the needs of waterbirds, and determined the optimal water level management scheme. In addition, we formulated planting principles, explored the planting structure under each water level regime, so that the plant structure can better serve the waterbirds. The results showed that the current water level regime of Hongze Lake is not consistent with the growth rhythm of aquatic plants. Because of the human regulation, the water level of the wetland is high in winter and low in summer, which is contrary to the requirements of aquatic plant growth. A combination of water level regimes and plant structure management, however, could effectively expand the area for waterbird habitat. The results of this study will help wetland managers to make informed decisions about how to restore the waterbird habitat in other similar regulated wetlands.
Using feathers to map continental-scale movements of waterbirds and wetland importance
Kate J. Brandis, Debashish Mazumder, Patricia Gadd, Boyu Ji, Richard T. Kingsford, Daniel Ramp
Abstract: Waterbirds are highly mobile, moving over large distances to access resources. Although consistent migration routes are observed in highly seasonal and predictable environments, movement patterns to utilize ephemeral resources in dryland environments are largely unknown. This makes conservation planning and water policy challenging as the relative importance of widely dispersed wetlands is difficult to rank. We addressed this challenge by combining a citizen science project with the novel application of X-ray fluorescence of feathers to detect continental scale movement of waterbirds using elemental signatures. By doing so, we gained important insight into the movements of 24 waterbird species, including the significance of the Murray-Darling basin as a key source of waterbirds across the continent. Our approach highlights the benefits of elemental signatures to identify key areas of habitat use and priorities for wetland management.
Jae Hyun Kim, Shinyeong Park, Seung Ho Kim, Eun Ju Lee
Abstract: The Hangang River and Imjingang River estuaries in Korea are part of the main transit route for many migratory birds that use the East Asia-Pacific flyway. Despite the global importance of this area as a seasonal bird stopover site and resting area, conservation areas have not been established in this area based on ecological properties. This study aimed to examine the umbrella effect of the white-naped crane (Antigone vipio), which is one of the best-known flagship species in East Asia, and to determine the effectiveness of establishing a conservation plan in the western DMZ based on the distribution of white-naped cranes. Species distribution modeling was performed for the white-naped crane; other threatened waterbirds wintering in the western DMZ; Group 1, including species with ecological traits similar to those of the white-naped crane; and Group 2, including species with ecological traits different from those of the white-naped crane. The modeling was based on field survey data from a citizen science project, and a systematic conservation planning approach was adopted for each species group. The results showed no significant differences between the plan for the target species and the plans for the other species groups, indicating that protecting white-naped cranes habitat can also protect the habitat of other threatened waterbirds.
Xiaoshan Fang, Renzhi Wu, Yongjun Feng, Yuanxin Huang, Shuang Liu, Li Yuan, Jincheng Liu, Xiaojun Niu, Xiangchun Wang, Huijian Hu
Abstract: The Haizhu National Wetland Park (HNWP) is the only national wetland park in a central megalopolis area in China. It was established to restore and conserve a damaged composite wetland ecosystem comprising urban rivers, inner lakes, and semi-natural forests with fruit trees in central Guangzhou. In 2013, our survey at HNWP revealed that the bird diversity was poor, which indirectly reflected the low habitat quality. Therefore, we proposed a restoration workflow based on species differential analysis (SDA) and implemented it in this area in 2013. The SDA method determined the bird species (i.e. target species) for which habitat could be restored by analyzing the existing, surrounding, and historical bird community in the area. We screened for target species using SDA and used these species as a basis for site zoning, habitat restoration projects, and recruitment measures. Both species richness and species diversity of the birds in the HNWP increased rapidly from 2014 to 2016 and remained stable in 2017 to 2018. In contrast, the species richness and species diversity in the control area where the SDA method was not used only reached the values of the area where this method was used in 2017. This shows that the SDA-based method could improve bird diversity effectively and rapidly. In addition, the proportion of waterbirds and migratory birds in the park also increased, indicating that the habitats that were restored for the waterbirds showed an improvement in quality.
Chukwuemeka Onwuka Martins, Oluwatobi Emmanuel Olaniyi, Mohamed Zakaria
Abstract: In Malaysia, multiple land use by humans has caused substantial losses of wetland ecosystems, and shrinkage of the populations, habitat and food bases of avian species. However, studies of avian populations, especially of waterbirds, is important, allowing us to understand the complexity of the wetland ecosystem structure, and also develop appropriate management techniques with robust monitoring tools to ensure the ecological sustainability of wetlands. This study aimed to determine the eco-climatic factors influencing the occurrence of waterbirds and to develop habitat suitability models for the Paya Indah (PIW) and Putrajaya wetlands (PW), Malaysia. A distance sampling point count technique using stratified random design was employed to survey the wetlands from November 2016 to January 2019. A total of 57 sampling points at 14 lakes at PIW and 54 sampling points at 24 lakes at PW were chosen. An automatic linear modelling algorithm and geographic information systems were employed to compute the importance ratios of 17 eco-climatic factors (hydrology 9; climate 5; waterscape 1 and landscape 2). The results revealed that all individual and estimated indices for observed waterbirds were significant. The automatic linear modelling algorithm results for PIW waterbirds also showed that the maximum and minimum weights of the factors were land cover and water dissolved oxygen, while in PW they were atmospheric pressure and Normalized Difference Water Index (NDWI). The maximum and minimum weights of the factors for waterbirds in PIW were water turbidity and electrical conductivity, while at PW they were atmospheric pressure and six water parameters. Large areas of Putrajaya Wetland were classified as more suitable for waterbirds than Paya Indah Wetland due to the favourable water pH, atmospheric pressure and land cover (forage availability). Thus, the models’ adoption as a management tool can help in the maintenance of the wetlands’ habitat quality and management effectiveness of waterbird species.
2) Conservation & management
Weipan Lei, Yang Wu, Fuxing Wu, Theunis Piersma, Zhengwang Zhang and José A. Masero
Abstract: Artificial wetlands such as coastal saltpans have replaced a number of coastal natural habitats worldwide and may have accommodated specific waterbird populations in the East Asian-Australasian Flyway (EAAF). The role of saltpans in the EAAF as foraging grounds for shorebirds is widely recognized, although their role as breeding grounds for waterbirds is very limited and contradictory. The Nanpu saltpans in northern Bohai Bay, China, are one of the largest saltpan complexes in the world. In this study, we monitored the nesting success (852 nests) of pied avocets (Recurvirostra avosetta) during three breeding seasons (2015, 2016, and 2018) in the Nanpu saltpans. The nest daily survival rate (DSR) was 0.970; hence, nest survival over the 27 exposure days was 44%. The apparent nest success was 51%. Surprisingly, 55% of nests failed during the laying period. Flooding and nest abandonment were the main causes of nest failure during both the laying and incubation periods. We found a strong positive relationship between the DSR and nest age, with nests that approached hatching having a greater probability of survival than freshly started nests. We also found a strong negative relationship between the DSR and precipitation, with the highest DSR observed for nests that experienced no precipitation. The DSR decreased over the course of the 71-days nesting season and followed a linear trend. The DSR was also density dependent and decreased slightly when nests were denser. A literature review showed that nest survival in the Nanpu saltpans was average compared with that of other studies and that nest success in artificial wetlands was significantly higher than that in natural wetlands or both habitats. Nevertheless, nest success decreased with the study date, suggesting that that breeding conditions for the pied avocet are worsening with time. The loss of saltpans could negatively affect the population of avocets and other ground-nesting waterbird species; therefore, conservation actions and research efforts should be strengthened to understand and conserve these functional wetlands for waterbirds.
Ecological Correlates of 20-Year Population Trends of Wintering Waterbirds in Deep Bay, South China
Yik-Hei Sung, Chun-chiu Pang, Tom Chung-hoi Li, Paulina Pui Yun Wong and Yat-tung Yu
Abstract: Along the East Asian-Australasian flyway (EAAF), waterbirds are threatened by a wide range of human activities. Studies have shown that wintering populations of many species have declined in Australia and Japan; however, long term data along China’s coast are limited. In this study, we analyzed data collected from monthly bird surveys to quantify population trends of wintering waterbirds from 1998 to 2017 in the Deep Bay area, South China. Of the 42 species studied, 12 declined, while nine increased significantly. Phylogenetic comparative analysis revealed that population trends were negatively correlated to reliance on the Yellow Sea and body size. Further, waterbird species breeding in Southern Siberia declined more than those breeding in East Asia. These findings, coupled with a relatively high number of increasing species, support the continual preservation of wetlands in the Deep Bay area. This study provides another case study showing that data collected from wintering sites provide insights on the threats along migratory pathway and inform conservation actions. As such, we encourage population surveys in the EAAF to continue, particularly along the coast of China.
Minghao Gong, Shiliang Pang, Zhongyan Gao, Wanyu Wen, Ling Zhang, Gang Liu, Huixin Li, Fawen Qian and Wenfeng Wang
Abstract: The endangered red-crowned crane (Grus japonensis, RCC) has the smallest population of all Chinese cranes, and is also susceptible to climate change because of its large body size, short migration distance, and specialized diet. We examined climate change-induced RCC habitat shifts and suggested some purposeful, resolute and crucial improvements needed to protect appropriate areas that ensure the RCC’s long-term survival. Based on monitored data of nesting locations and climate variables gathered from 2014 to 2017 around Zhalong Reserve on the Songnen Plain in northeast China, we used four General Circulation Models in Maxent modeling to project changes, including suitability and fragmentation, in RCC breeding habitat up to the year 2050. Based on climate change, we predicted a decline in 2050 of suitable and sub-suitable habitat from the current 26.2% to 14.3%-19.7% in the study area, but an even larger loss (from 71.3% to 27.3%-32%) of suitable habitat in Zhalong Reserve. The predictions also showed a northward movement of RCC habitat and a loss of current suitable habitat southeast of Zhalong Reserve, resulting in a discrepancy between future habitat areas and currently protected areas. In addition, climate change will further fragment RCC habitat, thus decreasing habitat suitability and carrying capacity, especially within Zhalong Reserve. Our study indicated that the most suitable breeding habitat is currently restricted to the Reserve. This finding partially explains that the low rate of RCC population growth is likely because of the limit of RCC’s expansion due to spatial patterns of suitable habitat. We confirmed that temperature, rather than precipitation, had the most impact on RCC breeding. To cope with climate change, we recommend that new refuges be designed within the study area and the transformation of wetland to farmland in the area be banned. Also, organic agriculture methods and crop species that consume less water than rice should be adopted to mitigate the adverse climate changes that accompany global warming and will contribute to RCC habitat degradation.
Habitat Suitability Assessment of Wintering Herbivorous Anseriformes in Poyang Lake, China
Megersa Tsegaye Debela, Qingming Wu, Zhe Li, Xueying Sun, Opelele Omeno and Yibin Li
Abstract: To design a good conservation strategy for herbivorous Anseriformes wintering in Poyang Lake, knowledge of habitat suitability is essential. Therefore, this study aimed to assess the habitat suitability of herbivorous Anseriformes of China’s Poyang Lake. Landsat images with a resolution of 30 m downloaded from the United States Geological Survey, and other ancillary data were used. The ENVI 5.3 software and ArcGIS 10.2 software were used for preprocessing, classifying the satellite image, and mapping habitat suitability. The study reveals that land cover types were divided into vegetation, mudflats, water, and sand. Similarly, the study area’s habitats were also divided into unsuitable, fair, good, and best grades. However, the distribution of the habitat suitability for each grade reveals significant spatial variations. For instance, vegetation indicated the areas with the best habitat grade, followed by mudflats, and these areas cover (47.93%, 2015 and 55.78%, 2019) the majority of the study area. The unsuitable grades cover the smallest areas (0.48%) of the lake. Similarly, this study results showed a slight change in habitat suitability areas. Therefore, this study highlighted that Poyang Lake has valuable importance for the conservation of herbivorous Anseriformes. Extending the years of study and including some ecological variables from different stopovers could improve the results.
Zhengtao Zhu, Wenxin Huai, Zhonghua Yang, Da Li, Yisen Wang
Abstract: Poyang Lake is located in the middle and lower reaches of the Yangtze River in China. It is the most important wintering area for the endangered Siberian cranes. Identifying the scale characteristics of habitat selection for Siberian cranes is essential for habitat conservation. In this study, a habitat suitability index (HSI) model based on multiscale habitat features was developed to assess the distribution and fragmentation degree of the suitable habitat for Siberian cranes before and after the construction of the proposed Poyang Lake Hydraulic Project (PLHP). The habitat of the entire lake area was divided into four ranks on the basis of HSI values. 2D shallow-water equations (SWEs), combined with remote sensing and geographic information system technology, were utilized to determine the key habitat features. Results indicated that the established HSI model could effectively recognize the potentially suitable habitats for Siberian cranes in Poyang Lake. The highly suitable habitat in the wet year was larger than that in the dry year, and the complexity of patch shapes and patch fragmentation increased. The influence of the PLHP on the suitable habitat for cranes mainly depended on its regulated water level, and this project could promote the formation and reduce the fragmentation degree of the suitable habitat under a properly regulated water level in the dry year. However, a higher regulated water level may cause a considerable negative impact on the distribution of suitable habitats in both years. This study provided a quantitative method to evaluate the potentially suitable habitats for Siberian cranes, and it could serve as a reference for the water level management of the proposed PLHP.
Jie Liang, Qianfang Meng, Xin Li, Yujie Yuan, Yuhui Peng, Xiaodong Li, Shuai Li, Ziqian Zhu, MingYan
Abstract: Hydrology-climate changes and food availability are expected to be the primary drivers that result in a loss of waterbirds diversity. Non-biological factors are vital to food availability in interconnected river-lake systems, so in addition to identifying the ecological response to drivers, it is also important to analyze and quantify relationships between drivers. In order to explore the impacts of these drivers on the wintering waterbirds, we selected Dongting Lake (DTL) as a study area, which is a typical interconnected river-lake system in the middle and lower reaches of the Yangtze River Floodplain. The Anatidae species, most of which are herbivorous, were chosen as the representative waterfowl. The Pearson correlation coefficient was applied to select variables related to the timing of water recession and food availability, which have significant influences on the Anatidae. Then, the structural equation model (SEM) was carried out to quantify the relationships among the food availability, hydrological variables, and climatic variables. The results showed that unseasonably early or late water recession had a negative impact on the diversity of the Anatidae, and in particular affected population dynamics of the Lesser White-fronted goose Anser erythropus. Significant changes in Anatidae populations in DTL occurred in response to maximum NDVI (r = 0.53, p<0.01) and the interval time of water recession (r = -0.43, p<0.1). Water level, flow, and interval time of water recession explained 71% of maximum NDVI in DTL. In addition, hydraulic interactions between the mainstream and each lake jointly affected the inundation pattern and the vegetation growth stage oldie lake after the flood season, thus affecting foraging suitability. Our findings suggest that water compensation should be carried out within an appropriate range of hydraulic gradient to optimize the time of water recession and improve the suitability of the habitat effectively. (C) 2021 Elsevier B.V. All rights reserved.
Xiaoyu Yu, Wenbin Zhu, Jiaxing Wei, Shaofeng Jia, Andong Wang, Yanbo Huang, Yajie Zhao
Abstract: With abundant resources in the wetland, the Yellow River Delta provides important habitats for various kinds of rare bird species. However, due to climate change and human water withdrawal activities, no-flow events of the Yellow River occurred frequently since the 1970s, resulting in serious wetland degradation and biodiversity losses. Ecological water supplement has been regarded as one of the most effective measures to cope with these environmental problems. Accordingly, how much water is required for the ecological restoration becomes an essential question to be answered. Since the primary function of the Yellow River Delta Natural Reserve (YRDNR), the typical wetland in the Yellow River Delta, is to provide suitable habitats for various rare birds, the purpose of this paper is to propose a method based on water balance analysis to specify monthly ecological water supplement for the habitats of typical birds in the YRDNR. Specifically, three typical birds were selected as the protection objects, including Grus japonensis, Ciconia boyciana, and Larus saundersi. Monthly water supplement was determined by monthly long-term time series data (2003-2018) of evapotranspiration product derived from remote sensing and meteorological data (precipitation and pan evaporation) acquired from National Meteorological Information Center. The results showed that the annual ecological water supplement for 10 km2 ideal habitats was 666.17 x 104 m3, 1165.22 x 104 m3, and 664.48 x 104 m3 for G. japonensis, C. boyciana, and L. saundersi, respectively. Besides, it was found that annual precipitation generally had a significant negative relation with annual ecological water supplement, which suggested that local precipitation should be considered as a key factor in determining the amount of annual water supplement. The frequency analysis was then implemented to provide reasonable scheme of actual ecological water supplement under different precipitation scenarios. The results indicated that annual ecological water supplement for the whole YRDNR was 1.81 x 108 m3, 1.94 x 108 m3, 2.10 x 108 m3 and 2.25 x 108 m3 respectively under wet, average, dry and extreme dry conditions. If water storage measurements are implemented to store surplus precipitation under rainy season, the average volume would reduce by nearly 10%.
Cheng Wang, Gang Wang, Lingjun Dai, Hongyu Liu, Yufeng Li, Chunqi Qiu, Yi Zhou, Hao Chen, Bin Dong, Yongqiang Zhao, Yanan Zhang
Abstract: In recent years, due to human activities and global climate change, the number and area of waterbird habitats in Yancheng coastal wetlands, a newly established world natural heritage site, have been shrinking, the function of the waterbird habitats has been degraded to varying degrees, and the safety of waterbird populations and habitats has been threatened. Therefore, in this study, waterbird habitat functions at the regional scale were assessed by using spatial principal component analysis (SPCA). According to the load matrix of principal components and the Redundancy analysis (RDA) method, the driving force of habitat function change and the mechanisms of their effects on waterbird guilds and diversity were revealed. The results showed that the areas of the highest and high habitat function grades continued to decline from 1987 to 2019, and the areas of the lowest and low grades of habitat function continued to increase. The overall habitat functions in the waterbird distribution areas were high, but the functional grades within different habitat sites were obviously decreasing. The main driving factors affecting habitat function change in Yancheng coastal wetlands from 1987 to 2019 were habitat types, habitat area, habitat diversity, habitat fragmentation, number of residential areas and reclamation intensity. The effects of these driving factors on the population diversity and distribution of waterbird guilds were different. Finally, countermeasures and suggestions for the functional maintenance and key node restoration of waterbird habitats in Yancheng coastal wetlands were proposed.
Function of restored wetlands for waterbird conservation in the Yellow Sea coast
Jun Fan, Xiaodan Wang, Wei Wu, Weipin Chen, Qiang M, Zhijun Ma
Abstract: To reduce the harm to wildlife caused by habitat loss and degradation, significant resources have been invested in habitat restoration worldwide. However, whether restored habitats can support wildlife communities similar to those natural ones remains unclear. Providing habitat for waterbirds, which are dependent on wetland for their survival, is a major target in many wetland restoration practices. Here we conducted a year-round waterbird survey at Chongming Dongtan, a national nature reserve established for waterbird conservation in the south Yellow Sea, in order to compare the characteristics of waterbird communities in four wetland types: restored wetlands, natural tidal wetlands, and two artificial wetlands (fish ponds and farmlands). We determined whether waterbird diversity and species composition differed among the wetland types. The results indicated that waterbird diversity, in terms of species richness, individual density, Shannon-Wiener diversity, functional diversity, and phylogenetic diversity, was generally similar in the restored and natural wetlands and was higher in the restored and natural wetlands than in fish ponds or farmlands. Most threatened species and exclusive species occurred in both natural and restored wetlands, but the overall species composition significantly differed between natural and restored wetlands. Non-metric multidimensional scaling analysis also indicated that waterbird community significantly differed among the wetland types. The results suggest that restored wetlands support substantial waterbird diversity but cannot replace natural wetlands because they lack the period tides that many tideland specialists (shorebirds) depend on. This study highlights the importance of protecting natural wetlands for waterbird conservation. We propose that both the diversity and species composition of wildlife communities should be considered in evaluating the effectiveness of habitat restoration for wildlife. (C) 2020 Elsevier B.V. All rights reserved.
3) Avian Influenza / Others
Feng Wen, Jing Yang, Jinyue Guo, Congying Wang, Qing Cheng, Zheng Tang, Kaijian Luo, Sheng Yuan, Shujian Huang & Yong Li
Abstract: Background Highly pathogenic avian influenza viruses (HPAIVs) of H5 subtype pose a great threat to the poultry industry and human health. In recent years, H5N6 subtype has rapidly replaced H5N1 as the most predominate HPAIV subtype circulating in domestic poultry in China. In this study, we describe the genetic and phylogenetic characteristics of a prevalent H5N6 strain in Guangdong, China. Results Nucleotide sequencing identified a H5N6 subtype HPAIV, designated as A/chicken/Dongguan/1101/2019 (DG/19), with a multibasic cleavage site in the hemagglutinin (HA). Phylogenetic analysis revealed DG/19 was a reassortant of H5N1, H5N2, H5N8, and H6N6 subtypes of avian influenza viruses. A number of mammalian adaptive markers such as D36N in the HA were identified. Conclusions Our results showed that HPAIV H5N6 strains still emerge in well-managed groups of chicken farms. Considering the increasing prevalence of H5N6 HPAIV, and the fact that H5N6 HPAIVs are well adapted to migratory birds, an enhanced surveillance for the East Asian-Australasian flyway should be undertaken to prevent potential threats to the poultry industry and human health.
Bethany J. Hoye, Celeste M. Donato, Simeon Lisovski, Yi-Mo Deng, Simone Warner, Aeron C. Hurt, Marcel Klaassen, and Dhanasekaran Vijaykrishna
Abstract: Australian lineages of avian influenza A viruses (AIVs) are thought to be phylogenetically distinct from those circulating in Eurasia and the Americas, suggesting the circulation of endemic viruses seeded by occasional introductions from other regions. However, processes underlying the introduction, evolution and maintenance of AIVs in Australia remain poorly understood. Waders (order Charadriiformes, family Scolopacidae) may play a unique role in the ecology and evolution of AIVs, particularly in Australia, where ducks, geese, and swans (order Anseriformes, family Anatidae) rarely undertake intercontinental migrations. Across a 5-year surveillance period (2011 to 2015), ruddy turnstones (Arenaria interpres) that “overwinter” during the Austral summer in southeastern Australia showed generally low levels of AIV prevalence (0 to 2%). However, in March 2014, we detected AIVs in 32% (95% confidence interval [CI], 25 to 39%) of individuals in a small, low-density, island population 90 km from the Australian mainland. This epizootic comprised three distinct AIV genotypes, each of which represent a unique reassortment of Australian-, recently introduced Eurasian-, and recently introduced American-lineage gene segments. Strikingly, the Australian-lineage gene segments showed high similarity to those of H10N7 viruses isolated in 2010 and 2012 from poultry outbreaks 900 to 1,500 km to the north. Together with the diverse geographic origins of the American and Eurasian gene segments, these findings suggest extensive circulation and reassortment of AIVs within Australian wild birds over vast geographic distances. Our findings indicate that long-term surveillance in waders may yield unique insights into AIV gene flow, especially in geographic regions like Oceania, where Anatidae species do not display regular inter- or intracontinental migration. IMPORTANCE High prevalence of avian influenza viruses (AIVs) was detected in a small, low-density, isolated population of ruddy turnstones in Australia. Analysis of these viruses revealed relatively recent introductions of viral gene segments from both Eurasia and North America, as well as long-term persistence of introduced gene segments in Australian wild birds. These data demonstrate that the flow of viruses into Australia may be more common than initially thought and that, once introduced, these AIVs have the potential to be maintained within the continent. These findings add to a growing body of evidence suggesting that Australian wild birds are unlikely to be ecologically isolated from the highly pathogenic H5Nx viruses circulating among wild birds throughout the Northern Hemisphere.
Yu BonMana, Ka Lai Chow, Feng Zhang, Kim Man Lei, Anna Oi Wah Leung, Wing Yin Mo, Ming HungWong
Abstract: Water, sediment and biota (two fish and one shrimp species) samples were collected from rivers, ponds, mudflat and estuaries within the Mai Po Ramsar site in Hong Kong, China, to determine the concentrations of heavy metals/loid (HMs): cadmium (Cd), copper (Cu), mercury (Hg), lead (Pb), zinc (Zn), and arsenic (As). The mutagenicity and toxicity of water and sediment samples were evaluated using Ames test and Microtox (R) bioassay, respectively. Ecological risk assessments on water birds were also conducted based on HM concentrations in biota, sediment and water samples. In general, results showed that downstream of Shan Pui River and Ng Tung River had relatively higher HM concentrations (e.g. Cu: 0.992-9.49 mu g/L; As: 0.342-5.83 mu g/L) when compared with estuaries (Cu: 0.400-3.69 mu g/L; As: 0.220-0.931 mu g/L) and ponds (Cu: 0.0402-2.41 mu g/L; As: 0.0501-2.10 mu g/L), except Hg and Cd. On the other hand, sediment samples collected fromNg Tung River showed mutagenicity on Salmonella typhimurium tester strain TA100, while the mudflat samples had mutagenicity on tester strain TA98 used in the Ames tests. Microtox (R) bioassay indicated that only sediment of Ng Tung River showed acute toxicity with a 15 min half maximal effective concentration (EC50) value of 30.5%. Results of ecological risk assessments showed that grey heron (Ardea cinerea), which feeds on fish and shrimps at Shan Pui River and ponds were not at risk. However, common sandpiper (Actitis hypoleucos), which feeds at ponds were subjected to a potential health risk due to its behavior of seeking food from the sediments, especially this bird species has a small body size. This indicates juvenile birds of other species may also be affected. Remediation should be implemented to relief the potential risk of Cu and Pb, to these water birds in the Mai Po Ramsar site.
Minoru Nakao and Mizuki Sasaki
Abstract: The cryptic diversity of trematodes was evaluated in the Nagayama-Shinkawa River, an artificial canal of the Ishikari River System of Hokkaido, Japan. Numerous migratory waterfowls use the canal as a stopover point in every spring season. The lymnaeid snail, Radix auricularia, and the semisulcospirid snail, Semisulcospira libertina, colonize the static and flowing water areas, respectively. The trematode fauna of the two snails was assessed by molecular phylogenetic and population genetic analyses. Each of distinctive clades in mitochondrial DNA trees was arbitrarily set as a species. In total, 14 species of the families Diplostomidae, Echinostomatidae, Notocotylidae, Plagiorchiidae, and Strigeidae occurred in R. auricularia, wherease S. libertina harbored 10 species of the families Echinochasmidae, Heterophyidae, Notocotylidae, and Lecithodendridae and Cercaria creta, an unclassified species whose adult stage is still unknown. The species diversity of the larval trematodes could be recognized as a “hot spot”, suggesting that the seasonal visit of waterfowls is very important to spread trematodes and to keep their diversity. A high intraspecific genetic diversity was observed in the echinostomatid, notocotylid, echinochasmid, and heterophyid species, whose definitive hosts include birds. It seems likely that each of the parasite populations is always disturbed by repeated visits of waterfowls.
Effects of Food Changes on Intestinal Bacterial Diversity of Wintering Hooded Cranes (Grus monacha)
Nazhong Zhang, Lizhi Zhou, Zhuqing Yang and Jingjing Gu
Abstract: As food is recognised as an important factor affecting the intestinal microbiota, seasonal changes in diet can influence the community composition. The hooded crane (Grus monacha) is an endangered migratory waterbird species, with some of the population wintering in the sallow lakes in the middle and lower Yangtze River floodplain. Their food resources have changed seasonally, with a reduction resulting from wetland degradation. To cope with seasonal changes in food availability, hooded cranes must constantly adjust their foraging strategies to survive. We studied the effect of changes in diet on the intestinal bacterial diversity of hooded cranes at Shengjin Lake, using faecal microanalysis and high-throughput sequencing. The results show that the main foods of hooded cranes were Polygonum criopolitanum, Oryza sativa, and Carex spp., which were significantly related to the composition of the intestinal bacterial community. In addition, foods available from the similar habitats were more similar, and the corresponding hooded crane intestinal bacteria were also more similar. The relative abundance of Lactobacillus acidipiscis in January and March was significantly higher than in November. Our research shows that the intestinal bacteria of hooded cranes actively adapt to diet changes to overcome the negative impact of the reduction in food resources, which is vital to the survival of hooded cranes.
Zhuqing Yang and Lizhi Zhou
Abstract: Diversity of gut microbes is influenced by many aspects, including the host internal factors and even direct or indirect contact with other birds, which is particularly important for mixed-species wintering waterbird flocks. In this study, Illumina high-throughput sequencing was used to analyze the intestinal bacteria of the hooded crane and bean goose whose niches overlap at Shengjin Lake. We tested whether contact time enhances the trans-species spread of gut bacteria. Results indicate alpha-diversity and microbial composition displayed significant separation between the two hosts in every wintering period, although the number of bacteria types shared increased with increasing contact time. For the same species, with the lengthening of contact time, alpha-diversity and the number of operational taxonomic units (OTUs) in the host intestine augmented, and the common OTUs and structural similarity of microflora in the middle and late periods were more than in the early and middle periods. In addition, we found a very high proportion of shared pathogens. Our results indicate that, although intestinal microflora of different species were separated, direct or indirect contact in the mixed-species flock caused the spread of gut bacteria trans-species, indicating that more attention should be paid to intestinal pathogens in wild birds.
