The Qinghai-Tibet Plateau serves as a critical hub along the Central Asian Flyway (CAF) and a recognized hotspot for the emergence of highly pathogenic avian influenza (HPAI) viruses. Despite recurrent outbreaks, the migratory dynamics of key reservoir species, such as the Brown-headed Gull (Chroicocephalus brunnicephalus) and their potential contributions to viral dissemination remain poorly understood. Here, we integrated highresolution GPS telemetry with Bayesian discrete phylogeographic analyses to investigate the potential association between migration and HPAI H5Nx dissemination. Based on tracking data from 11 individuals, we identified 5 major life-history stages and 12 important stopover sites used during migration, including 6 in autumn and 6 in spring, and characterized their spatiotemporal distribution patterns. Phylogenetic reconstruction showed that three independent introductions of HPAI H5Nx viruses occurred on the Qinghai-Tibet Plateau between 2021 and 2024, all involving strains associated with Brown-headed Gulls and classified into the 2021-H5N8 I, 2021-H5N8 II, and 2022-H5N1 clusters. These viral clusters were distributed primarily along the CAF and the East Asian-Australasian Flyway (EAAF), with diffusion patterns broadly consistent with the spatiotemporal dynamics of migratory birds. Notably, the spread of the 2022-H5N1 cluster along the CAF was highly concordant with the migratory route and phenology of Brown-headed Gulls, while host transition analysis suggested that gulls may serve as bridging hosts in interspecies transmission. Together, these findings suggest that Brown-headed Gulls may contribute to the cross-regional dissemination and interspecies transmission of HPAI H5Nx viruses, and highlight the value of combining tracking data with viral genomics for cross-border surveillance.

Currently, large-scale above-ground biomass (AGB) estimation mainly depends on the area-based approach (ABA). However, with advancements in individual tree detection technology and the availability of multi-platform remote sensing data, the individual tree-based approach (ITA) presents new opportunities for accurate, nondestructive AGB estimation. Nevertheless, research on integrating ITA with ABA for scaling AGB estimates from individual trees to the regional level remains limited. This study introduced an innovative hybrid framework incorporating ITA and ABA for regional-scale estimation of forest AGB through the combination of handheld, unmanned, and satellite LiDAR, together with Landsat 8 imagery. The results demonstrated that the segmentation of individual trees using a fusion of unmanned aerial vehicle laser scanning (ULS) and handheld laser scanning (HLS) was effective (r = 0.84, p = 0.76, F-score = 0.79) for the secondary forests in northeast China (NEC), particularly achieving high accuracy of diameter at breast height (DBH) with R2 = 0.93 and RMSE of only 1.84 cm. Both individual tree and plot-level AGB estimates achieved satisfactory accuracy, with biases of -3.9 kg and -16,56 Mg/ha, respectively. The error-in-variable (EIV) model was established for stand-level AGB estimation using the plot AGB estimates from ITA (R2 = 0.69; RMSE = 19.59 Mg/ha; rRMSE = 15.1%) and employed to estimate footprint-level AGB based on the canopy height data extracted from ICESat-2/ATL08, significantly expanding the limited sample size (by 150 times) for regional AGB estimation. Two periods (2019-2020, 2021-2022) of continuous AGB of NEC were mapped using the integrated method of random forests (RF) and empirical Bayesian Kriging (EBK). The accuracy of the RF-EBK model is markedly enhanced in comparison to that of the RF model for AGB estimation (R2 increased by about 37% - 49%, RMSE and rRMSE declined by 25%). This study provides technical support for upscaling AGB estimation from individual tree to extensive forest and lays a solid foundation for precise forestry, sustainable forest management, and the attainment of carbon neutrality.

Avian avulavirus (AAVV) is a significant pathogen affecting avian species, but research on its prevalence in wild birds in China has been relatively limited. In this study, active surveillance for AAVV was conducted in wild birds in China from 2003 to 2020. A total of 124,882 samples were collected from 26 provinces, and 220 AAVV-positive samples were identified, encompassing various serotypes including AAVV-1, -4, -6, -8, -9, -13, and -16. Notably, AAVV-9 isolates were reported for the first time in China through this study. Detailed genetic analysis of 148 representative strains revealed that 26 of them exhibited a polybasic amino acid residue at the F gene cleavage site, a molecular marker associated with virulent AAVV strains in chickens. The geographical isolation between the Old and New Worlds has led to the independent evolution of AAVVs in each region, resulting in distinct Eurasian and North American lineages. Our findings predominantly aligned with the Eurasian lineage. However, repeated detections of AAVVs of North American origin in wild birds in China suggests potential viral dispersal between North America and China, which warrants further investigation. Furthermore, geographical reconstruction of AAVV-4 occurrence indicated a possible transmission route from Europe to East Asia. The origin of AAVV-4 remains uncertain due to limited sequence data, underscoring the need for expanded surveillance and highlight the necessity for sustained, long-term epidemiological surveillance efforts.

H6 avian influenza virus is widely prevalent in wild birds and poultry and has caused human infection in 2013 in Taiwan, China. During our active influenza surveillance program in wild waterfowl at Poyang Lake, Jiangxi Province, an H6N2 AIV was isolated and named A/bean goose/JiangXi/452-4/2013(H6N2). The isolate was characterized as a typical low pathogenic avian influenza virus (LPAIV) due to the presence of the amino acid sequence PQIETR↓GLFGAI at the cleavage site of the hemagglutinin (HA) protein. The genetic evolution analysis revealed that the NA gene of the isolate originated from North America and exhibited the highest nucleotide identity (99.29

ABSTRACTThe Amur tiger, a flagship species in wildlife conservation in China, was the focus of this study, which is aimed at detecting viral infections that could threaten the survival of this population. A total of 60 Amur tigers were examined, including 21 blood samples and 60 nasopharyngeal swab samples. Various PCR methods were used to detect the viruses: standard PCR was applied to identify feline parvovirus (FPV), nested PCR for feline herpesvirus‐1 (FHV‐1), feline calicivirus (FCV), feline coronavirus (FCoV), feline leukemia virus (FeLV), feline immunodeficiency virus (FIV), and qPCR for canine distemper virus (CDV) and influenza A virus (IAV). The results showed that 70.0% (42/60) of the tigers tested positive for at least one viral infection. Specifically, the prevalence of FPV, FHV‐1, and FCoV were 14.3% (3/21), 26.7% (16/60), and 56.7% (34/60), respectively. A co‐infection rate of 21.4% (9/42) was observed among infected tigers. No positive results were found for FCV, FIV, FeLV, CDV, or IAV. Overall, this is the first study to detect the presence of FCoV in Amur tigers in China and confirms their exposure to FPV, FHV‐1, and FCoV.

Birds are sensitive to environmental changes and can drive range shifts rapidly due to their high mobility. Though previous studies have examined the associations between species traits and range shifts, whether species traits could still explain heterogeneity in shift directions remains poorly explored. Here, we compiled new bird records of China from 2000 to 2019 and analyzed species traits associated with apparent shift directions. We collected 350 provincial-level new records of birds belonging to 67 families of 22 orders. Of these, 32 are threatened, with 3 critically endangered, 11 endangered, and 18 vulnerable. Provinces in western China (i.e., Yunnan and Xizang) had relatively higher species richness of new recorded birds; this pattern was also reflected in the phylogenetic diversity we observed. In addition, provinces in northern China (i.e., Tianjin, Shandong, and Beijing) had relatively higher richness-controlled phylogenetic diversity. Phylogenetic overdispersion of new recorded bird communities was observed in 61.29% of provinces (19 of 31). The main shift directions indicated by new bird records were northward (with nearly 50% of birds moving NW, N and NE). Migration, hand-wing index (HWI), body mass, and range size are the four key factors that most significantly influence the shift directions in bird species, suggesting that bird movement toward newly suitable areas varies with species-specific traits. Together, these results demonstrate the importance of considering species ecological traits when predicting shift directions of birds.

H10 subtype avian influenza viruses (AIVs) have been isolated from wild and domestic avian species worldwide and have occasionally crossed the species barrier to mammalian hosts. Fatal human cases of H10N8 infections and the recent detection of human H10N3 infections have drawn widespread public attention. In this study, 25 H10Nx viruses were isolated from wild waterfowl in China during a long-term surveillance of AIVs. We conducted phylogenetic and phylogeographic studies of the hemagglutinin (HA) genes of global H10 viruses to determine the spatiotemporal patterns of spread and the roles of different hosts in viral transmission. We found the pattern of AIV transmission from wild birds to poultry to humans, and Anatidae have acted as the seeding population in the spread of the virus. Phylogenetic incongruence indicated complex reassortment events and our isolates were divided into eight genotypes (G1-8). We also found that the HA genes of the G8 viruses belonged to the North American lineage, indicating that intercontinental gene flow has occurred. Their receptor-binding specificity showed that the G1/4/5/6/7/8 viruses bind to both human-type α2,6-linked sialic acid receptors and avian-type α2,3-linked sialic acid receptors. Mouse studies indicated that the H10Nx isolates replicated efficiently in the respiratory system without preadaptation, but showed low pathogenicity in mice. The H10Nx isolates showed no (G2/4/7) or low pathogenicity (G1/3/5/6/8) in chickens, and the G6 and G8 viruses could be transmitted to chickens through direct contact. The asymptomatic shedding of these wild-bird-origin H10Nx isolates in chickens and their good adaptation in mice should increase the ease of their transmission to humans, and they therefore pose a threat to public health. Our findings demonstrate a further understanding of wild bird-origin H10 viruses and provide information for the continuous surveillance of H10 subtype viruses.

Habitat, climate, and human disturbances have important effects on wildlife, and these are especially critical for threatened species. In this study, we used infrared camera traps to monitor the population dynamics of the hazel grouse (Tetrastes bonasia) from 2012 to 2021 in northeast China and explore the effects of habitat, climate, and human disturbance on their distribution. We analyzed 16 environmental variables related to significant differences between presence recordings and absence recordings within and between seasons. Temperatures and roads influenced the distribution of the hazel grouse, but topography and vegetation types did not. The hazel grouse preferred deciduous forest and oak forest from spring to autumn. This study provides ecological information to help guide the mountain habitat management of the hazel grouse in national parks.

The Ethylene Responsive Factor (ERF) transcription factor family is important for regulating plant growth and stress responses. Although the expression patterns of ERF family members have been reported in many plant species, their role in Populus alba × Populus glandulosa, an important model plant for forest research, remains unclear. In this study, we identified 209 PagERF transcription factors by analyzing the P. alba × P. glandulosa genome. We analyzed their amino acid sequences, molecular weight, theoretical pI (Isoelectric point), instability index, aliphatic index, grand average of hydropathicity, and subcellular localization. Most PagERFs were predicted to localize in the nucleus, with only a few PagERFs localized in the cytoplasm and nucleus. Phylogenetic analysis divided the PagERF proteins into ten groups, Class I to X, with those belonging to the same group containing similar motifs. Cis-acting elements associated with plant hormones, abiotic stress responses, and MYB binding sites were analyzed in the promoters of PagERF genes. We used transcriptome data to analyze the expression patterns of PagERF genes in different tissues of P. alba × P. glandulosa, including axillary buds, young leaves, functional leaves, cambium, xylem, and roots, and the results indicated that PagERF genes are expressed in all tissues of P. alba × P. glandulosa, especially in roots. Quantitative verification results were consistent with transcriptome data. When P. alba × P. glandulosa seedlings were treated with 6% polyethylene glycol 6000 (PEG6000), the results of RT-qRCR showed that nine PagERF genes responded to drought stress in various tissues. This study provides a new perspective on the roles of PagERF family members in regulating plant growth and development, and responses to stress in P. alba × P. glandulosa. Our study provides a theoretical basis for ERF family research in the future.

Artificial nest boxes are placed to attract birds to nest and breed in a specific location,and they are widely used in avian ecology research and in the attraction of insectivorous birds.There is evidence that artificial nest boxes can adversely affect breeding fitness but no great focus has been placed on this issue by researchers.Therefore,we retrieved 321 research papers regarding artificial nest boxes published from 2003 to 2022 and used the ’Biblioshiny’ program to extract and integrate keywords;we then summarized the adverse effects of artificial nest boxes on avian breeding success.The studies highlighted many drawbacks and misuses in the designing and placement of nest boxes;furthermore,bird attraction was decreased by their inappropriate selection,thus reducing breeding success.Regarding nest box production,there were shortcomings in the construction material,color,smell,and structural design of the boxes used.Nest boxes were also placed at inappropriate densities,locations,orientations,heights,and managed incorrectly.Finally,we propose suggestions for more efficient and safer artificial nest boxes for future use in avian ecology research and bird conservation.

Highly pathogenic avian influenza （HPAI） subtype H5Nx viruses have spread globally and are a major concern for poultry,wild birds,mammals,and even humans （de Vries et al.2015;Zeng et al.2022）.The hemagglutinin （HA）genes of H5 subtype viruses have evolved into multiple clades and some of these clades have been further divided into subclades （Cui et al.2022）.Clade 2.3.4.4H5N8 HPAI viruses （HPAIVs） have caused several waves of disease outbreaks in wild birds and domestic poultry（Wang et al.2022）.

H5N8 and H5N1 highly pathogenic avian influenza viruses (AIVs) of clade 2.3.4.4b were isolated from dead migratory birds and fecal samples collected in Tibet, China, in May 2021. Phylogenetic analyses showed that the viruses isolated in this study may have spread from wintering or stopover grounds of migratory birds in South Asia. We monitored two disparate clade 2.3.4.4b H5Nx viruses in migratory birds in Tibet during their breeding season. The data revealed that breeding grounds may exhibit a potential pooling effect among avian influenza viruses in different migratory populations. IMPORTANCE In this study, 15 H5N8 and two H5N1 highly pathogenic avian influenza viruses of clade 2.3.4.4b were isolated from dead migratory birds and fecal samples in Tibet, China. Isolates of H5N1 virus of clade 2.3.4.4b have been rarely reported in China. Our findings highlight that breeding grounds may exhibit a potential pooling effect among avian influenza viruses (AIVs) in different migratory populations. In addition to intensification of the surveillance of AIVs in migratory birds in Tibet, China, international cooperation should be strengthened.

In addition to landscape changes, urbanization also brings about changes in environmental factors that can affect wildlife. Despite the common referral in the published literature to multiple environmental factors such as light and noise pollution, there is a gap in knowledge about their combined impact. We developed a multidimensional environmental framework to assess the effect of urbanization and multiple environmental factors (light, noise, and temperature) on life-history traits and breeding success of Barn Swallows (Hirundo rustica) across rural to urban gradients in four locations spanning over 2500 km from North to South China. Over a single breeding season, we measured these environmental factors nearby nests and quantified landscape urbanization over a 1 km(2) radius. We then analysed the relationships between these multiple environmental factors through a principal component analysis and conducted spatially explicit linear-mixed effects models to assess their effect on life-history traits and breeding success. We were particularly interested in understanding whether and how Barn Swallows were able to adapt to such environmental conditions associated with urbanization. The results show that there is significant variation in the exposure to environmental conditions experienced by Barn Swallows breeding across urbanization gradients in China. These changes and their effects are complex due to the behavioural responses ameliorating potential negative effects by selecting nesting sites that minimize exposure to environmental factors. However, significant relationships between landscape urbanization, exposure to environmental factors, and life-history traits such as laying date and clutch size were pervasive. Still, the impact on breeding success was, at least in our sample, negligible, suggesting that Barn Swallows are extremely adaptable to a wide range of environmental features.

Animals can expand distributions in response to climatic and environmental changes, but the potential expansive ability of a source population is rarely evaluated using designed experiments. Group foraging can increase survival in new environments, but it also increases intraspecific competition. The trade-off between benefit and conflict needs to be determined. The expanding Light-vented Bulbul Pycnonotus sinensis was used as a model to test mechanisms promoting successful expansion. Social foraging and its advantages were evaluated using lab-designed feeding trials. Consuming novel foods was compared between bulbuls and a sympatric, nonexpansive relative species, the finchbill Spizixos semitorques, from native areas at both solitary and social levels. Bulbuls increased their eating times when transferred from solitary to group, whereas social context did not affect finchbills. Bulbuls were significantly more likely to eat with their companions than finchbills when in a group. Thus, exploring food resources in a bulbul source population was facilitated by social context, indicating that social foraging is an important means by which birds successfully expand and respond to environmental changes. This research increases understanding of successful expansion mechanisms and will consequently help predict invasive potentials of alien species.

Highly pathogenic influenza A(H5N8) viruses have caused several worldwide outbreaks in birds and are able cross the species barrier to infect humans, posing a substantial threat to public health. After the first detection of H5N8 viruses in deceased swans in Inner Mongolia, we performed early warning and active monitoring along swan migration routes in central China. We isolated and sequenced 42 avian influenza viruses, including 40 H5N8 viruses, 1 H5N2 virus, and 1 H9N2 virus, in central China. Our H5N8 viruses isolated in swan stopover sites and wintering grounds showed high nucleotide homologies in the whole genome, revealing a common evolutionary source. Phylogenetic analysis revealed that the H5 viruses of clade 2.3.4.4b prevalent in 2020 have further diverged into two sub-clades: b1 and b2. The phylogeographic analysis also showed that the viruses of sub-clade b2 most likely originated from poultry in Russia. Notably, whooper swans were found to be responsible for the introduction of sub-clade b2 viruses in central China; whooper and tundra swans play a role in viral spread in the Yellow River Basin and the Yangtze River Basin, respectively. Our findings highlight swans as an indicator species for transborder spreading and monitoring of the H5N8 virus.

Per-and polyfluoroalkyl substances (PFASs) have been omnipresent in the environment and marine organisms. However, little is known about these compounds and their associations with hematological parameters in dogs. In this research, we investigated the concentrations and distributions of PFASs in the blood of dogs and explored the associations between PFASs concentrations in blood and hematological parameters. Perfluorooctanoate (PFOA) was found to be the dominant PFAS in the blood (54.23%), followed by perfluorobutyric acid (PFBA) (16.05%) and perfluorooctanesulfonate (PFOS) (12.05%). On average, PFASs concentration in dogs was 3.553 ng/mL (SD: 2.146). Moreover, age is a key factor influencing the levels of PFBA, PFOA, and PFBS in males, as well as seven PFASs (6:2 Cl-PFESA, PFBA, PFOA, PFOS, PFHxS, PFDA, and PFNA) in female dogs' blood. The results revealed that PFHxS in dietary food accounted for most of the total daily PFASs consumption. We also discovered that greater PFASs exposure (including PFOA and PFOS) could significantly increase amylase (AMY) and decrease cholesterol (CHOL) levels. Furthermore, there are linear relationships between PFDA, PFNA and many biochemical parameters (AMY, CHOL, albumin/globulin (A/G), blood urea nitrogen (BUN), alkaline phosphatase (ALP), creatinine (CREA)). Thus, PFAS accumulation has a certain influence on dogs' health, and we must pay attention to the potential threat posed by these elements to dogs.

Feline immunodeficiency virus (FIV) naturally infects more than 20 kinds of felines and poses a serious threat to their health, but there has been little research on FIV in tigers. In this study, 320 captive Siberian tigers (225 from Harbin, 55 from Hailin, and 40 from Shenyang) were tested for FIV by nested PCR, and three Siberian tigers from Hailin were FIV positive (5.45%). From these three animals, FIV gene fragments, gag-p26 (444 nt) from samples HD094 and HD1786 and pol-RT (576 nt) and pol-RNase (730 nt) from sample HD631, were sequenced and found to share more than 99% sequence identity with FIV subtype A from domestic cats. This is the first time FIV has been detected in Siberian tigers in China.

The fact that wild felines are carriers of pernicious infectious viruses should be a major concern due to the potential cross-species transmission between the felines and human or domestic animals. However, studies on the virus in the captive wild felines, especially in tigers, are thin on the ground. In this study, we screened four infectious viruses, namely, feline parvovirus (FPV), feline coronavirus (FCoV), canine distemper virus (CDV), and influenza A virus (IAV), in the blood samples of 285 captive Siberian tigers (Panthera tigris altaica) and in the spleen samples of two deceased lions (Panthera leo), which were collected from 2019 to 2021 in three Siberian Tiger Parks from the northeast of China. Nucleic acids isolated from the blood samples collected from tigers and the spleen samples collected from two deceased lions were positive for FPV by PCR, and the positive rate was 4.6% (13/285) in tigers. Furthermore, the VP2 gene of FPV was amplified by nested PCR, and the sequences of the VP2 gene from these six FPV positive strains shared 98.3–99.9% homology with the reference. The key amino acid sites of VP2 protein were consistent with that of FPV reference strains. Phylogenetic analysis based on the VP2 gene showed that in this study, FPV-positive strains were grouped within the FPV clade and closely related to the Asian strains clade. The results of this study showed that FPV circulated in the captive Siberian tigers and lions in northeastern China and provided valuable information for the study of FPV epidemiology in wild felines. Therefore, we suggest that regular antibody monitoring and booster immunization for tigers should be performed.