Grus Nigricollis Research Articles

Mechanisms of enhancing genetic fitness in non-kinship-based groups: Insights from black-necked cranes

Mechanisms of enhancing genetic fitness in non-kinship-based groups: Insights from black-necked cranes

Black-necked crane as border object: interspecies politics in Himalayan borderlands

ABSTRACT Legacies of imperial frontier-making, ongoing border conflicts between nuclear armed nations, changing livelihoods, and the impact of anthropogenic climate change have created complicated claims on Himalayan borderland areas in the name of conservation, security, ethnic identity and development. Combining historical research with ethnography, this article traces the role of the Black-necked crane (grus nigricollis) in the formation of mid-nineteenth century imperial frontiers in the Himalayas and, subsequently, its present-day position in the political ecology of two Himalayan regions along the Sino-India border – Ladakh and Arunachal Pradesh. We introduce the concept of ‘border object’ and demonstrate how it can serve as a useful concept to understand how non-humans become participants in changing configurations of territoriality, biopolitics and science, which underpin both a past imperial frontier and present-day border regimes.

Migratory birds modulate niche tradeoffs in rhythm with seasons and life history

Movement is a key means by which animals cope with variable environments. As they move, animals construct individual niches composed of the environmental conditions they experience. Niche axes may vary over time and covary with one another as animals make tradeoffs between competing needs. Seasonal migration is expected to produce substantial niche variation as animals move to keep pace with major life history phases and fluctuations in environmental conditions. Here, we apply a time-ordered principal component analysis to examine dynamic niche variance and covariance across the annual cycle for four species of migratory crane: common crane (Grus grus, n = 20), demoiselle crane (Anthropoides virgo, n = 66), black-necked crane (Grus nigricollis, n = 9), and white-naped crane (Grus vipio, n = 9). We consider four key niche components known to be important to aspects of crane natural history: enhanced vegetation index (resources availability), temperature (thermoregulation), crop proportion (preferred foraging habitat), and proximity to water (predator avoidance). All species showed a primary seasonal niche "rhythm" that dominated variance in niche components across the annual cycle. Secondary rhythms were linked to major species-specific life history phases (migration, breeding, and nonbreeding) as well as seasonal environmental patterns. Furthermore, we found that cranes' experiences of the environment emerge from time-dynamic tradeoffs among niche components. We suggest that our approach to estimating the environmental niche as a multidimensional and time-dynamical system of tradeoffs improves mechanistic understanding of organism-environment interactions.

Seasonal changes in invertebrate diet of breeding black-necked cranes (Grus nigricollis).

Invertebrates greatly support the growth, development, and reproduction of insectivorous birds. However, the influence of human activity (e.g., pesticide use, deforestation, and urbanization) inevitably leads to a decrease in global arthropods. The diversity and variation in invertebrate diet influence the food composition of birds, especially species living in rapidly changing environments, such as the Tibetan Plateau. However, little is known of the seasonal variation in invertebrate diet in response to environmental changes. Here, we characterized the invertebrate diet composition in pre- and post-breeding black-necked crane (Grus nigricollis) using fecal metabarcoding. We identified 38 invertebrate genera; the top three were Tipula (82.1% of relative abundance), Ceramica (3.0%), and unclassified_Hymenoptera (2.5%), with Tipula predominated the diet in both seasons. We also observed 20 and 16 unique genera in the pre- and post-breeding periods, and the genera composition was distinct between seasons (R = .036, p = .024). In pre-breeding, black-necked cranes tended to consume more diverse foods, and individual cranes exhibited greater heterogeneity at the genus level. At the genera and species level, pre-breeding black-necked cranes showed a wider dietary niche than post-breeding cranes. We observed season-specific features, with Tipula (common crane fly) and Stethophyma (grasshoppers) being enriched in the post-breeding period and Ceramica (moth) being more abundant in the pre-breeding period. Three Tipula species had the greatest importance in discriminating between seasonal diets. This study demonstrated a seasonal pattern of invertebrate diet in the black-necked crane, suggesting diet composition in response to resource and species availability. These results elaborate on the foraging ecology of highland birds and can inform the management of black-necked crane conservation.

Gut fungi of black-necked cranes (Grus nigricollis) respond to dietary changes during wintering

BackgroundMigratory birds exhibit heterogeneity in foraging strategies during wintering to cope with environmental and migratory pressures, and gut bacteria respond to changes in host diet. However, less is known about the dynamics of diet and gut fungi during the wintering period in black-necked cranes (Grus nigricollis).ResultsIn this work, we performed amplicon sequencing of the trnL-P6 loop and ITS1 regions to characterize the dietary composition and gut fungal composition of black-necked cranes during wintering. Results indicated that during the wintering period, the plant-based diet of black-necked cranes mainly consisted of families Poaceae, Solanaceae, and Polygonaceae. Among them, the abundance of Solanaceae, Polygonaceae, Fabaceae, and Caryophyllaceae was significantly higher in the late wintering period, which also led to a more even consumption of various food types by black-necked cranes during this period. The diversity of gut fungal communities and the abundance of core fungi were more conserved during the wintering period, primarily dominated by Ascomycota and Basidiomycota. LEfSe analysis (P < 0.05, LDA > 2) found that Pyxidiophora, Pseudopeziza, Sporormiella, Geotrichum, and Papiliotrema were significantly enriched in early winter, Ramularia and Dendryphion were significantly enriched in mid-winter, Barnettozyma was significantly abundant in late winter, and Pleuroascus was significantly abundant in late winter. Finally, mantel test revealed a significant correlation between winter diet and gut fungal.ConclusionsThis study revealed the dynamic changes in the food composition and gut fungal community of black-necked cranes during wintering in Dashanbao. In the late wintering period, their response to environmental and migratory pressures was to broaden their diet, increase the intake of non-preferred foods, and promote a more balanced consumption ratio of various foods. Balanced food composition played an important role in stabilizing the structure of the gut fungal community. While gut fungal effectively enhanced the host’s food utilization rate, they may also faced potential risks of introducing pathogenic fungi. Additionally, we recongnized the limitations of fecal testing in studying the composition of animal gut fungal, as it cannot effectively distinguished between fungal taxa from food or soil inadvertently ingested and intestines. Future research on functions such as cultivation and metagenomics may further elucidate the role of fungi in the gut ecosystem.

Phytosociological Analysis of Bumdeling Ramsar site, Riverine Wetland of International Importance, Eastern Bhutan

The Kholongchu riverine wetlands in Bumdeling, Bhutan, are a unique ramsar site and crucial winter roosting grounds for the Black Necked Crane. Despite the area's notable ecological successions, recent information on plant diversity is less known from the wetland. In 2023, study was conducted to evaluate the phytodiversity and phytosociology of the Bumdeling Ramsar site (BRS) using quantitative quadrat analysis method. The study identified 165 plant species in a wetland, with Asteraceae being the most dominant family. Herbaceous plants dominate the wetland, followed by shrubs and grasses. The area has moderate floral species diversity with Simpson (0.87) and Shannon (2.59) diversity value. Floral species are evenly distributed, with no single species dominating vegetation with Simpson dominance (0.13). Menhinicks index (2.19) and Margalef (4.60) index indicate high species richness. Furthermore, Important Value Index indicated Persicaria hydropiper, Anaphalis margaritaceae, and Alnus nepalensis as the dominating and important plant species in the wetland. This study provides valuable floristic information for further scientific studies and management activities in BRS.

Variations of gut microbiota in the wintering black-necked crane (Grus nigricollis) at local and regional scales and its management implications

The composition of gut microbiota (and its dynamic) strongly influences the host organism’s health, and has been reported to be influenced by a variety of intrinsic and extrinsic factors in wild birds. However, most of the studies were carried out on a single geographical scale. A study incorporating comparison on multiple geographic scales should further improve our understanding of the contributing factors for avian gut microbiota. In this study, we compared the composition, diversity and function of gut microbiota among seven sub-divided populations of the black-necked crane (Grus nigricollis) wintering in Caohai wetland, China. Sequences on the V3-V4 region of 16 S rRNA were analyzed and compared to those of birds from the same breeding area, but distant wintering area in Dashanbao wetland. We observed microbiota divergences both within the Caohai wetland and between the two wetlands. Interestingly, the divergences between the two wetlands were much more pronounced than those within the Caohai wetland, strongly suggesting the determining effect of the external factors in this species. Core gut microbial operational taxonomic units were from the phyla Firmicutes, Proteobacteria, and Actinobacteria, which may be closely related in terms of dietary intake. Most importantly, we detected abundant potentially pathogenic bacteria in the Caohai wetland, which require monitoring efforts to avoid cross-species transmission between the birds and local poultry, livestock and residents. We further speculated that the shrinking of foraging grounds, with the resultant shortage of plant foods, led to an increase in fish-eating frequency in this species. We suggested that encouraging farmers to return to the wetland to grow agricultural plants would likely be a good solution.

Dynamic monitoring and restorability evaluation of alpine wetland in the eastern edge of Qinghai–Tibet Plateau

Accurate monitoring of alpine wetland areas and scientific evaluation of alpine wetland restorability play important roles in revealing the changing mechanism of the ecological environment. However, because of the complexity and lack of spatial data, few studies on evaluation index system of restorability of alpine wetland considered wild animal habitat, such as habitat suitability index of black necked crane. Based on Landsat images of seven periods from 1990 to 2020, this study adopts the methods of spectral mixture analysis and change vector analysis to quantitatively demonstrate the variations and distribution patterns of alpine wetland ecosystem in the eastern edge of Qinghai–Tibet Plateau. The study focuses on determining the abundance of water, vegetation and soil, which the interannual variations represent as the shapes of ‘√’, mirror ‘N’ and normal ‘N’, respectively. In terms of natural ecological condition and human activity interference, we construct a comprehensive evaluation model of restorability of alpine wetland, separate the restorability district and construct the Bayesian network model to discuss the causal relationship between the restorability value and evaluation factor. Results show that the regions of alpine wetland in the study area changed most drastically from 1995 to 2000 and from 2000 to 2005. In addition, the total areas classified as suitable, relatively suitable and suitable for restoration account for 63.69 % of the study area, with a large potential for wetland restorability. Moreover, the prioritisation scheme of wetland restoration action includes the valley swamps of Heihe River in the middle, followed by the flat wetlands and grasslands in the south and lastly by uneven wetlands in the north.

Analysis of winter survival strategies of sympatric black-necked cranes, and common cranes from the perspective of diet and gut microbiota

Wintering migratory birds have to travel thousands of kilometers between their breeding and wintering grounds because of their distinct habits. They experience complex and changing survival pressures throughout the winter. This study is the first to investigate the overwintering strategies of sympatric foraging black-necked cranes and common cranes from the perspectives of food and gut microbiota. Non-invasive sampling technique was used to collect stool samples. Sanger sequencing was used to determine the origin of the crane species identified from the samples. The analysis of plant-based food, the gut microbiota, and their interactions in the faeces was performed using high-throughput sequencing technology. It was found that in environments with limited aquatic vegetation, both the black-necked crane and the common crane increased their consumption of potatoes, accounting for more than 50% of their diets. Black-necked cranes also competed with common cranes for food, and they quickly adapted to changes in diet by horizontally transmitting their gut microbiota. To meet body needs, the common cranes—which could not compete with the black-necked cranes—constantly searched for new food sources. They increase the metabolism of amino acids, lipids and these metabolites to adapt to the competitive pressures and dietary changes. This study advances our knowledge of how diet and gut microbiota interact in plateau wetland birds, examining the competitive tactics of interwintering black-necked and common cranes', and provides recommendations for the re-vegetation in the Caohai wetlands and artificial feeding of the two crane species.

Comparative analysis of the intestinal microbiota of black-necked cranes (Grus nigricollis) in different wintering areas.

Fecal microbiota is essential for host health because it increases digestive effectiveness. The crane species Grus nigricollis (G. nigricollis) is considered to be near threatened. The fecal microbial composition of crane is less understood, particularly in the Tibet, China. This study was performed to investigate the differences in fecal microbial composition and diversity of crane in different wintering areas using third-generation single-molecule real-time sequencing technology in the Tibet, China. According to the findings, 20 samples were used to generate 936 bacterial amplicon sequence variants (ASVs) and 1,800 fungal ASVs, only 4 bacterial ASVs and 20 fungal ASVs were shared in four distinct locations. Firmicutes were the dominant bacterial phylum in all samples, and Ascomycota and Basidiomycota were the dominant fungal phylum. At the genus level, Lactobacillus was the dominant genus in Linzhi City (LZ), Shannan City (SN), and Lasa City (LS), whereas Megamonas was the dominant genus in Rikaze City (RKZ). Naganishia and Mycosphaerella were the dominant fungal genera in SN and RKZ. Mycosphaerella and Tausonia were the dominant fungal genera in LZ. Naganishia and Fusarium were the dominant fungal genera in LS. And the fecal microbial composition varied between the four groups, as shown by the underweighted pair-group method with arithmetic means and principal coordinates analysis. This study offers a theoretical basis for understanding the fecal microbial composition of crane.

Metabarcoding of protozoa and helminth in black-necked cranes: a high prevalence of parasites and free-living amoebae.

Parasites and free-living amoebae (FLA) are common pathogens that pose threats to wildlife and humans. The black-necked crane (Grus nigricollis) is a near-threatened species and there is a shortage of research on its parasite diversity. Our study aimed to use noninvasive methods to detect intestinal parasites and pathogenic FLA in G. nigricollis using high-throughput sequencing (HTS) based on the 18S rDNA V9 region. A total of 38 fresh fecal samples were collected in Dashanbao, China, during the overwintering period (early-, middle I-, middle II-, and late-winter). Based on the 18S data, eight genera of parasites were identified, including three protozoan parasites: Eimeria sp. (92.1%) was the dominant parasite, followed by Tetratrichomonas sp. (36.8%) and Theileria sp. (2.6%). Five genera of helminths were found: Echinostoma sp. (100%), Posthodiplostomum sp. (50.0%), Euryhelmis sp. (26.3%), Eucoleus sp. (50.0%), and Halomonhystera sp. (2.6%). Additionally, eight genera of FLA were detected, including the known pathogens Acanthamoeba spp. (n=13) and Allovahlkampfia spp. (n=3). Specific PCRs were used to further identify the species of some parasites and FLA. Furthermore, the 18S data indicated significant changes in the relative abundance and genus diversity of the protozoan parasites and FLA among the four periods. These results underscore the importance of long-term monitoring of pathogens in black-necked cranes to protect this near-endangered species.

Host genetic background rather than diet-induced gut microbiota shifts of sympatric black-necked crane, common crane and bar-headed goose

IntroductionGut microbiota of wild birds are affected by many factors, and host genetic background and diet are considered to be two important factors affecting their structure and function.MethodsIn order to clarify how these two factors influence the gut microbiota, this study selected the sympatric and closely related and similar-sized Black-necked Crane (Grus nigricollis) and Common Crane (Grus grus), as well as the distantly related and significantly different-sized Bar-headed Goose (Anser indicus). The fecal samples identified using sanger sequencing as the above three bird species were subjected to high-throughput sequencing of rbcL gene and 16S rRNA gene to identify the feeding types phytophagous food and gut microbiota.ResultsThe results showed significant differences in food diversity between black-necked cranes and Common Cranes, but no significant differences in gut microbiota, Potatoes accounted for approximately 50% of their diets. Bar-headed Geese mainly feed on medicinal plants such as Angelica sinensis, Alternanthera philoxeroides, and Ranunculus repens. Black-necked cranes and Common Cranes, which have a high-starch diet, have a similar degree of enrichment in metabolism and synthesis functions, which is significantly different from Bar-headed Geese with a high-fiber diet. The differences in metabolic pathways among the three bird species are driven by food. The feeding of medicinal plants promotes the health of Bar-headed Geese, indicating that food influences the functional pathways of gut microbiota. Spearman analysis showed that there were few gut microbiota related to food, but almost all metabolic pathways were related to food.ConclusionThe host genetic background is the dominant factor determining the composition of the microbiota. Monitoring the changes in gut microbiota and feeding types of wild birds through bird feces is of great reference value for the conservation of other endangered species.

Identification of Multiple Novel Viruses in Fecal Samples of Black-Necked Cranes Using Viral Metagenomic Methods.

The black-necked crane is the only species of crane that lives in the high-altitude region of the Tibet Plateau. At present, there is little research on viral diseases of the black-necked crane (Grus nigricollis). In this study, a viral metagenomic approach was employed to investigate the fecal virome of black-necked cranes in Saga County, Shigatse City, Tibet, China. The identified virus families carried by black-necked cranes mainly include Genomoviridae, Parvoviridae, and Picornaviridae. The percentages of sequence reads belonging to these three virus families were 1.6%, 3.1%, and 93.7%, respectively. Among them, one genome was characterized as a novel species in the genus Grusopivirus of the family Picornaviridae, four new parvovirus genomes were obtained and classified into four different novel species within the genus Chaphamaparvovirus of the subfamily Hamaparvovirinae, and four novel genomovirus genomes were also acquired and identified as members of three different species, including Gemykroznavirus haeme1, Gemycircularvirus ptero6, and Gemycircularvirus ptero10. All of these viruses were firstly detected in fecal samples of black-necked cranes. This study provides valuable information for understanding the viral community composition in the digestive tract of black-necked cranes in Tibet, which can be used for monitoring, preventing, and treating potential viral diseases in black-necked cranes.

Local farmers' perceptions of ecosystem services and disservices provided by the Black-necked Crane (Grus nigricollis) and their conservation implications

Local farmers' perceptions of ecosystem services and disservices provided by the Black-necked Crane (Grus nigricollis) and their conservation implications

An improved comprehensive model for assessing the heavy metals exposure towards waterbirds: A case report from Black-necked cranes (Grus nigricollis) in Caohai Wetland, China

Heavy metal contamination poses a significant environmental threat to wildlife on global scale, making accurate assessment of exposure risk crucial for conservation efforts, particularly for vulnerable species. Existing risk assessment models have been widely used, but their construction process lacks comprehensive considerations. In this study, we constructed an optimized health risk assessment model based on the well-established "Liu's model" and "ADI model", and applied the pollution allocation factor (AF) to accurately assess the risk of heavy metal exposure to wildlife. Our model was applied to assess exposure risk of heavy metal for the black-necked crane(Grus nigricollis), a flagship species in the alpine wetland ecosystem of Caohai Wetland. Soil, plant and black-necked crane fecal samples were collected from the Caohai Wetland and surrounding areas in Guizhou, China. We revealed varying degrees of As, Cd, Cr, Ni, Pb, and Zn contamination in soil and plants from different habitats, exceeding the background or plant limit values. This indicated that the black-necked crane and other waterbirds living in Caohai Wetland are suffering with the multi-elemental heavy metal contamination, especially in the gutterway and grassland. The exposure dose of As, Cd, Cr, Ni, Cu, and Zn toward black-necked cranes differed significantly in soil and plant pathways (P < 0.05). As, Cd, Cu, and Zn were mainly derived from plants consumption, while Cr and Ni originated from soil. Considering the contribution of soil and plant pathways to heavy metal exposure in black-necked cranes, the exposure doses of each elements calculated via food intake accounted for over half of the exposure calculated via feces (AF>0.5). The risk assessment model identified Cr and Pb were the highest risk elements for black-necked cranes, with exposure risk simulated through feces exceeding those through food. These findings suggested that current Liu's model may underestimate the effects of other pathways and medium. Therefore, we proposed a more comprehensive and accurate model for evaluating the exposure risk of black-necked cranes, incorporating AF to quantify the contribution of risk sources to black-necked cranes and understand their overall health risk. This model can serve as a useful tool for the conservation and habitat quality improvement of the black-necked cranes and other waterbirds.

Overwintering Cranes, Waders, and Shorebirds versus Ducks and Coots Showed Contrasting Long-Term Population Trends in Caohai Wetland in Guizhou Province, China

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

Autumn migration of black-necked crane (Grus nigricollis) on the Qinghai-Tibetan and Yunnan-Guizhou plateaus.

Despite previous research efforts, the majority migration routes of the black-necked cranes (Grus nigricollis) have remained veiled. In this study, we utilized satellite telemetry data from 45 cranes between 2015 and 2021 to unveil critical insights. Our results revealed 11 distinct autumn migration routes and one sedentary flock, of which eight routes and the sedentary flock were previously undocumented. Our findings highlighted the remarkable diversity in the migration routes of black-necked cranes, especially in terms of migration orientations, spatial-temporal patterns, and altitudinal movement patterns. Cranes breeding on the eastern, northern, and central Qinghai-Tibetan Plateau migrated southward, while those on the northern slopes of the Himalayas migrated eastward, westward, northward, or opted to remain sedentary. Moreover, we expanded the known range of migration distances to 84-1520 km at both ends (excluding sedentary individuals) and identified two long-term (Da Qaidam and Chaka) and one short-term (Gyatong grassland) stopover sites. Furthermore, our study revealed that the breeding colonies in the Qilian Mountains on the northeastern Qinghai-Tibetan Plateau utilized long-term stopover sites before embarking on significant altitude ascent, while other flocks displayed more urgent migration patterns, preferring to roost only at night. By unveiling the near-complete autumn migration routes of black-necked cranes, our research has contributed to discovering the critical habitats and connectivity among various breeding colonies, which is instrumental in developing effective seasonal conservation plans.

Adjusting the protected areas on the Tibetan Plateau under changing climate

The intensifying climate change crisis threatens the distribution within ecosystems and their function. Protected areas should incorporate the changing climate into planning to improve the effectiveness of biological conservation, particularly for biodiversity hotspots facing fast climate change. In this study, we investigated the climate-smart planning for protected areas in the Tibetan Plateau, known as the Third Pole, under climate change scenarios. These areas comprise unique ecosystems and three biodiversity hotspots of the world. The Species distribution model and carbon model with a systematic conservation planning tool (Marxan) were coupled in a unified framework. The economic costs (population) and climate costs (climate velocity, namely, a metric reflecting the impacts of climate change on species shifts) were input into the Marxan model to conduct hierarchical planning and further identify the areas functioning as species conservation priority areas or climate refugia under different climate scenarios. Results showed that nearly 10 % of the existing protected areas would suffer from rapid climate change in the future, leading to climate space loss in current protected areas by more than 20 %. The hierarchical planning realized relatively low economic and climate costs but left 58 % gap areas outside current conservation network. Therefore, six adjustable areas in the eastern and southern Tibetan Plateau, particularly in the margins of the plateau, were identified as: the gap areas (1) adjacent to the southwest of Qilian Mountains, (2) on the southeast of the headwaters of the Yellow River, (3) on the southeast of the headwaters of the Lancang River, (4) in Zayu and Mêdog, (5) connecting Mount Qomolangma Nature Reserve and Middle Reaches of the Yarlung Zangbo Valley—the Black-necked Cranes Nature Reserve, and (6) in the northwest of Zanda. These areas were proved to perform complex ecological functions under future climate scenarios. Our findings emphasize the necessity to account for climate impacts on protected area planning. The framework can help enhance the ability of the Tibetan Plateau as ecological security barrier and guide the climate-smart design of protected areas in China.

Genomic and Pathologic Characterization of the First FAdV-C Serotype 4 Isolate from Black-Necked Crane.

Fowl adenoviruses (FAdVs) are distributed worldwide in poultry and incriminated as the etiological agents for several health problems in fowls, and are capable of crossing species barriers between domestic and wild fowls. An FAdV strain was, for the first time, isolated from black-necked crane in this study, and was designated as serotype 4 Fowl aviadenovirus C (abbreviated as BNC2021) according to the phylogenetic analysis of its DNA polymerase and hexon gene. The viral genomic sequence analysis demonstrated that the isolate possessed the ORF deletions that are present in FAdV4 strains circulating in poultry fowls in China and the amino acid mutations associated with viral pathogenicity in the hexon and fiber 2 proteins. A viral challenge experiment with mallard ducks demonstrated systemic viral infection and horizontal transmission. BNC2021 induced the typical clinical signs of hepatitis-hydropericardium syndrome (HHS) with swelling and inflammation in multiple organs and showed significant viral replication in all eight organs tested in the virus-inoculated ducks and their contactees at 6 dpi. The findings highlight the importance of surveillance of FAdVs in wild birds.

Changes in the landscape patterns of Black-necked Crane habitat and its correlation with their individual population numbers during the past 40 years in China.

The landscape pattern of the Black-necked Crane (Grus nigricollis) habitat in China changed at different spatial scales and long-term periods due to natural factors and human activities, and habitat reduction and fragmentation threatened the survival of Black-necked Cranes. The factors driving the habitat landscape pattern and individual population changes of Black-necked Cranes remain to be studied. In this paper, based on remote sensing data of land use from 1980 to 2020, the changes in landscape pattern and fragmentation of the Black-necked Crane habitat in China over 40 years were analyzed from two different spatial scales using the land cover transfer matrix and landscape index. The correlation between landscape and Black-necked Crane individual population was analyzed. The most obvious observations were as follows: (1) Although transformation between landscapes occurred to varying degrees, the area of wetlands and arable land in the breeding and the wintering areas (net) increased significantly from 1980 to 2020. (2) Habitat fragmentation existed in the breeding and the wintering area and was more obvious in the wintering area. (3) The number of individuals of Black-necked Cranes increased period by period, and habitat fragmentation did not inhibit their population growth. (4) The number of individuals of Black-necked Crane was closely related to the wetland and arable land. The increasing area of wetlands and arable and the increasing landscape shape complexity all contributed to the growth of the individual population. The results also suggested that the number of individuals of Black-necked Crane was not threatened by the expanding arable land in China, and they might benefit from arable landscapes. The conservation of Black-necked Cranes should focus on the relationship between individual Black-necked Cranes and arable landscapes, and the conservation of other waterbirds should also focus on the relationship between individual waterbirds and other landscapes.