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Aim: Understanding changes in the behaviour of threatened species responding to rapidly increasing human disturbances is critical for biodiversity conservation. Here, we synthesize a meta‐analysis of the cumulative effect of human disturbances on the behaviour of global threatened terrestrial mammals. Location: Global terrestrial ecosystem. Time Period: Data collected from 1993 to 2021. Major Taxa Studied: Terrestrial mammals. Results: There were significant differences in behavioural changes among categories of human disturbances (i.e. biological invasion, climate change, grazing, habitat degradation, protection management, road traffic and tourism). The effect size of road traffic on behavioural change was the largest and particularly led habitat selection to be more specialized. The effect size for habitat degradation on foraging behaviour was the largest, and the effect mainly led to a shorter time spent in foraging and a change in food selection. Changes to behaviour increased with human disturbance intensity and varied among species according to their functional traits including body mass, food habits, migration and group type. Climate change, grazing, road traffic and tourism had a greater effect on larger species. The effect size for habitat degradation on omnivorous species was the largest, while carnivorous and solitary species were more sensitive to tourism, and migratory species were especially vulnerable to climate changes. Main Conclusions: The diverse human disturbances interact with disturbance intensity, and some species' functional traits significantly affected the behavioural change in threatened terrestrial mammals. Such behavioural changes away from predisturbance patterns may have consequences for their fitness and community interactions. The management and conservation of threatened species should incorporate knowledge of their behavioural responses to human disturbance and take into account the potential ecological consequences for biodiversity conservation. [ABSTRACT FROM AUTHOR]

The giant panda (Ailuropoda melanoleuca) is an iconic bear native to China, famous for eating almost exclusively bamboo. This unusual dietary behavior for a carnivore is enabled by several key adaptations including low physical activity, reduced organ sizes and hypothyroidism leading to lowered energy expenditure. These adaptive phenotypes have been hypothesized to arise from a panda-unique single-nucleotide mutation in the dual-oxidase 2 (DUOX2) gene, involved in thyroid hormone synthesis. To test this hypothesis, we created genome-edited mice carrying the same point mutation as the panda and investigated its effect on metabolic phenotype. Homozygous mice were 27% smaller than heterozygous and wild-type ones, had 13% lower body mass-adjusted food intake, 55% decreased physical activity, lower mass of kidneys (11%) and brain (5%), lower serum thyroxine (T4: 36%), decreased absolute (12%) and mass-adjusted (5%) daily energy expenditure, and altered gut microbiota. Supplementation with T4 reversed the effects of the mutation. This work uses a state-of-the-art genome editing approach to demonstrate the link between a single-nucleotide mutation in a key endocrine-related gene and profound adaptive changes in the metabolic phenotype, with great importance in ecology and evolution. [ABSTRACT FROM AUTHOR]

The giant panda (Ailuropoda melanoleuca) is an iconic mammal, but the function of its black-and-white coloration is mysterious. Using photographs of giant pandas taken in the wild and state-of-the-art image analysis, we confirm the counterintuitive hypothesis that their coloration provides camouflage in their natural environment. The black fur blends into dark shades and tree trunks, whereas white fur matches foliage and snow when present, and intermediate pelage tones match rocks and ground. At longer viewing distances giant pandas show high edge disruption that breaks up their outline, and up close they rely more on background matching. The results are consistent across acuity-corrected canine, feline, and human vision models. We also show quantitatively that the species animal-to-background colour matching falls within the range of other species that are widely recognised as cryptic. Thus, their coloration is an adaptation to provide background matching in the visual environment in which they live and simultaneously to afford distance-dependent disruptive coloration, the latter of which constitutes the first computational evidence of this form of protective coloration in mammals. [ABSTRACT FROM AUTHOR]

Traits of organisms are shaped by their living environments and also determined in part by their phylogenetic relationships. For example, phylogenetic relationships often affect the geographic distributions of animals and cause variation in their living environments, which usually play key roles in the life history and determine the functional traits of species. As an ancient family of mammals, bears widely distribute and have evolved some specific strategies for survival and reproduction during their long‐term evolutionary histories. Many studies on the ecology of bears have been conducted in recent decades, but few have focused on the relationships between their geographic distributions and ecological adaptations. Here, using bears as a model system, we collected and reanalyzed data from the available literatures to explore how geographic distributions and phylogenetic relationships shape the functional traits of animals. We found a positive relationship between phylogenetic relatedness and geographic distributions, with bears distributed in adjacent areas applying more similar strategies to survive and reproduce: (a) Bears living at high latitudes consumed a higher proportion of vertebrates, which may provide more fat for adaptation to low temperatures, and (b) their reproduction rhythms follow fluctuations in seasonal forage availability and quality, in which bears reach mating status from March to May and give birth in approximately November or later. [ABSTRACT FROM AUTHOR]

Antagonistic coevolution between host and parasite drives species evolution. However, most of the studies only focus on parasitism adaptation and do not explore the coevolution mechanisms from the perspective of both host and parasite. Here, through the de novo sequencing and assembly of the genomes of giant panda roundworm, red panda roundworm, and lion roundworm parasitic on tiger, we investigated the genomic mechanisms of coevolution between nonmodel mammals and their parasitic roundworms and those of roundworm parasitism in general. The genome-wide phylogeny revealed that these parasitic roundworms have not phylogenetically coevolved with their hosts. The CTSZ and prolyl 4-hydroxylase subunit beta (P4HB) immunoregulatory proteins played a central role in protein interaction between mammals and parasitic roundworms. The gene tree comparison identified that seven pairs of interactive proteins had consistent phylogenetic topology, suggesting their coevolution during host–parasite interaction. These coevolutionary proteins were particularly relevant to immune response. In addition, we found that the roundworms of both pandas exhibited higher proportions of metallopeptidase genes, and some positively selected genes were highly related to their larvae's fast development. Our findings provide novel insights into the genetic mechanisms of coevolution between nonmodel mammals and parasites and offer the valuable genomic resources for scientific ascariasis prevention in both pandas. [ABSTRACT FROM AUTHOR]

Many factors, including the inner status of the individuals and external environment, can influence the parasite infections and stress physiology in mammals. Here, we explored the influence of the sex, age, reproductive season and seasonal food availability on the parasitism and stress physiology in wild giant pandas (Ailuropoda melanoleuca) through nutrient and steroid hormone analysis and parasitic infection measurement. Diet composition had significant influences on the faecal cortisol levels and parasite load of wild giant pandas. The seasonal dynamic of the cortisol levels and parasite load in faeces co-vary with the seasonal nutrient intake levels of the pandas, which concurrently arrived the peaks at the wood bamboo shoot-eating period in May (parasite infection intensity, 41.47 ± 12.11 eggs/g of wet faeces; cortisol levels, 619.34 ± 70.55 ng/g dry faeces) that the nutrition intake by wild pandas was the highest (protein/fibre, 69.23 ± 9.93). Meanwhile, age class is also as an important factor to affect the parasite load and stress physiology of wild giant pandas. Cubs and sub-adults suffered more helminth burden and stress physiology than adults and old individuals. This is the first study to evaluate the inner and external factors influence on parasitism and stress physiology in wild giant pandas. The findings facilitate a better understanding of how environmental factors might influence the physiology, behaviour and health of pandas and other species and have implications for the conservation and management of the endangered species. [ABSTRACT FROM AUTHOR]

Competition often occurs between two or more sympatric species that use similar ecological niches. During competition, a superior species may exclude the competitor from parts of its fundamental niche or make it go extinct. Determining the potential competition between two sympatric species including an endangered one has important implications for conservation management. We evaluated potential food competition between the wild boar and the giant panda in a key national nature reserve established primarily for the giant panda protection. We monitored foraging plots for 9 years, conducted food macronutrient analysis, and combined our analysis with long-term population monitoring results for two species. The wild boar population increased dramatically in the past 18 years, benefiting from conservation policies of the Chinese government, whereas the giant panda population decreased. We found evidence for competition for bamboo shoots, an important seasonally limiting resource. The wild boar had a higher utilization rate at foraging plots than giant panda, which also avoided plots used by wild boar. This study indicates key seasonal food competition may exist between wild boar and giant panda. This competition for a key food resource may have negative impacts on giant panda populations, particularly under the substantial increase of the wild boar, yet this possibility has not figured prominently in conservation planning and policy for panda reserves. We suggest long-term monitoring of this competitive relationship across reserves to determine when and where management intervention is needed. And, we might need more flexible policies instead of the current "one size fits all" one. [ABSTRACT FROM AUTHOR]

Understanding the interaction between life history, demography and population genetics in threatened species is critical for the conservations of viable populations. In the context of habitat loss and fragmentation, identifying the factors that underpin the structuring of genetic variation within populations can allow conservationists to evaluate habitat quality and connectivity and help to design dispersal corridors effectively. In this study, we carried out a detailed, fine‐scale landscape genetic investigation of a giant panda population from the Qinling Mountains for the first time. With a large microsatellite data set and complementary analysis methods, we examined the role of isolation‐by‐barriers (IBB), isolation‐by‐distance (IBD) and isolation‐by‐resistance (IBR) in shaping the pattern of genetic variation in this giant panda population. We found that the Qinling population comprises one continuous genetic cluster, and among the landscape hypotheses tested, gene flow was found to be correlated with resistance gradients for two topographic factors, slope aspect and topographic complexity, rather than geographical distance or barriers. Gene flow was inferred to be facilitated by easterly slope aspect and to be constrained by topographically complex landscapes. These factors are related to benign microclimatic conditions for both the pandas and the food resources they rely on and more accessible topographic conditions for movement, respectively. We identified optimal corridors based on these results, aiming to promote gene flow between human‐induced habitat fragments. These findings provide insight into the permeability and affinities of giant panda habitats and offer important reference for the conservation of the giant panda and its habitat. [ABSTRACT FROM AUTHOR]

An upsurge in anthropogenic impacts has hastened the decline of the red panda (Ailurus fulgens). The red panda is a global conservation icon, but holistic conservation management has been hampered by research being restricted to certain locations and population clusters. Building a comprehensive potential habitat map for the red panda is imperative to advance the conservation effort and ensure coordinated management across international boundaries. Here, we use occurrence records of both subspecies of red pandas from across their entire range to build a habitat model using the maximum entropy algorithm (MaxEnt 3.3.3k) and the least correlated bioclimatic variables. We found that the subspecies have separate climatic spaces dominated by temperature‐associated variables in the eastern geographic distribution limit and precipitation‐associated variables in the western distribution limit. Annual precipitation (BIO12) and maximum temperature in the warmest months (BIO5) were major predictors of habitat suitability for A. f. fulgens and A. f. styani, respectively. Our model predicted 134,975 km2 of red panda habitat based on 10 percentile thresholds in China (62% of total predicted habitat), Nepal (15%), Myanmar (9%), Bhutan (9%), and India (5%). Existing protected areas (PAs) encompass 28% of red panda habitat, meaning the PA network is currently insufficient and alternative conservation mechanisms are needed to protect the habitat. Bhutan's PAs provide good coverage for the red panda habitat. Furthermore, large areas of habitat were predicted in cross‐broader areas, and transboundary conservation will be necessary. Building a comprehensive potential habitat map for red panda is imperative to progress conservation effort. Thus, we build a habitat model using species occurrence records, least correlated bioclimatic variables, and topographic features using machine‐learning maximum entropy algorithm. Globally, the model predicted 134,975 km2 as habitat of red panda in the landscape including 28% habitat under protected area networks. [ABSTRACT FROM AUTHOR]

Abstract: Major histocompatibility complex genes (MHC), a gene cluster that controls the immune response to parasites, are regarded as an important determinant of mate choice. However, MHC‐based mate choice studies are especially rare for endangered animals. The giant panda (Ailuropoda melanoleuca), a flagship species, has suffered habitat loss and fragmentation. We investigated the genetic variation of three MHC class II loci, including DRB1, DQA1, and DQA2, for 19 mating‐pairs and 11 parent‐pairs of wild giant pandas based on long‐term field behavior observations and genetic samples. We tested four hypotheses of mate choice based on this MHC variation. We found no supporting evidence for the MHC‐based heterosis, genetic diversity, genetic compatibility and “good gene” hypotheses. These results suggest that giant pandas may not use MHC‐based signals to select mating partners, probably because limited mating opportunities or female‐biased natal dispersal restricts selection for MHC‐based mate choice, acknowledging the caveat of the small sample size often encountered in endangered animal studies. Our study provides insight into the mate choice mechanisms of wild giant pandas and highlights the need to increase the connectivity and facilitate dispersal among fragmented populations and habitats. [ABSTRACT FROM AUTHOR]

Inbreeding can have negative consequences on population and individual fitness, which could be counteracted by inbreeding avoidance mechanisms. However, the inbreeding risk and inbreeding avoidance mechanisms in endangered species are less studied. The giant panda, a solitary and threatened species, lives in many small populations and suffers from habitat fragmentation, which may aggravate the risk of inbreeding. Here, we performed long-term observations of reproductive behaviour, sampling of mother-cub pairs and large-scale genetic analyses on wild giant pandas. Moderate levels of inbreeding were found in 21.1% of mating pairs, 9.1% of parent pairs and 7.7% of panda cubs, but no high-level inbreeding occurred. More significant levels of inbreeding may be avoided passively by female-biased natal dispersal rather than by breeding dispersal or active relatedness-based mate choice mechanisms. The level of inbreeding in giant pandas is greater than expected for a solitary mammal and thus warrants concern for potential inbreeding depression, particularly in small populations isolated by continuing habitat fragmentation, which will reduce female dispersal and increase the risk of inbreeding. [ABSTRACT FROM AUTHOR]

In response to seasonal variation in quality and quantity of available plant biomass, herbivorous foragers may alternate among different plant resources to meet nutritional requirements. Giant pandas ( Ailuropoda melanoleuca) are reliant almost exclusively on bamboo which appears omnipresent in most occupied habitat, but subtle temporal variation in bamboo quality may still govern foraging strategies, with population-level effects. In this paper, we investigated the possibility that temporal variation in the quality of this resource is involved in population regulation and examined pandas' adaptive foraging strategies in response to temporal variation in bamboo quality. Giant pandas in late winter and early spring consumed a less optimal diet in Foping Nature Reserve, as the availability of the most nutritious and preferred components and age classes of Bashania fargesii declined, suggesting that bamboo may be a seasonally limiting resource. Most panda mortalities and rescues occurred during the same period of seasonal food limitation. Our findings raised the possibility that while total bamboo biomass may not be a limiting factor, carrying capacity may be influenced by subtle seasonal variation in bamboo quality. We recommend that managers and policy-makers should consider more than just the quantity of bamboo in the understory and that carrying capacity estimates should be revised downward to reflect the fact that all bamboos are not equal. [ABSTRACT FROM AUTHOR]

Stable isotope analysis is very useful in animal ecology, especially in diet reconstruction and trophic studies. Differences in isotope ratios between consumers and their diet, termed discrimination factors, are essential for studies of stable isotope ecology and are species-specific and tissue-specific. Given the specialized bamboo diet and clear foraging behavior, here, we calculated discrimination factors for carbon and nitrogen isotopes from diet to tissues (tooth enamel, hair keratin and bone collagen) for the giant panda ( Ailuropoda melanoleuca), a species derived from meat-eating ancestors. Our results showed that carbon discrimination factor obtained from giant panda tooth enamel (ε 13Cdiet-enamel = 10.0‰) and nitrogen discrimination factors from hair keratin (Δ15Ndiet-hair = 2.2‰) and bone collagen (Δ15Ndiet-collagen = 2.3‰) were lower, and carbon discrimination factors from hair keratin (Δ13Cdiet-hair = 5.0‰) and bone collagen (Δ13Cdiet-collagen = 6.1‰) were higher than those of other mammalian carnivores, omnivores and herbivores. Such distinctive values are likely the result of a low-nutrient and specialized bamboo diet, carnivore-like digestive system and exceptionally low metabolism in giant pandas. [ABSTRACT FROM AUTHOR]

Understanding population size and genetic diversity is critical for effective conservation of endangered species. The Amur tiger ( Panthera tigris altaica) is the largest felid and a flagship species for wildlife conservation. Due to habitat loss and human activities, available habitat and population size are continuously shrinking. However, little is known about the true population size and genetic diversity of wild tiger populations in China. In this study, we collected 55 fecal samples and 1 hair sample to investigate the population size and genetic diversity of wild Amur tigers in Hunchun National Nature Reserve, Jilin Province, China. From the samples, we determined that 23 fecal samples and 1 hair sample were from 7 Amur tigers: 2 males, 4 females and 1 individual of unknown sex. Interestingly, 2 fecal samples that were presumed to be from tigers were from Amur leopards, highlighting the significant advantages of noninvasive genetics over traditional methods in studying rare and elusive animals. Analyses from this sample suggested that the genetic diversity of wild Amur tigers is much lower than that of Bengal tigers, consistent with previous findings. Furthermore, the genetic diversity of this Hunchun population in China was lower than that of the adjoining subpopulation in southwest Primorye Russia, likely due to sampling bias. Considering the small population size and relatively low genetic diversity, it is urgent to protect this endangered local subpopulation in China. [ABSTRACT FROM AUTHOR]

Eight adult (six male and two female) wild Qinling giant pandas ( Ailuropoda melanoleuca qinlingensis) from China National Foping Nature Reserve were tracked, and their dental data collected and recorded from October 2010 to April 2014. Each panda had dental abnormalities of varying severity. Dental wear and fracture were the most common conditions. Absent teeth were common, with premolars missing most often. Mild caries were present in five molar teeth between two animals. Different degrees of dental plaque and calculus occurred in all animals but without severe periodontal disease. Two animals with severe dental abnormalities died due to intestinal problems. Large segments of bamboo were found in their intestinal tracts, and intestinal perforation and ulcers were evident, indicating dental abnormalities can be an important factor in the health of wild giant pandas and may lead to death. Further research with larger sample sizes of wild and captive giant pandas will be required to substantiate the relationship between dental abnormalities and mortality in giant pandas. [ABSTRACT FROM AUTHOR]

Food resources are patchily distributed in the environment and carnivores and herbivores have adopted different foraging strategies to maximize feeding efficiency. One interesting strategy is that of the giant panda, a member of the Carnivora that has evolved into a bamboo specialist. Giant pandas forage discriminately, but it remains unknown how nutritional hierarchical levels and landscape configuration heterogeneity affect foraging patch selection. Here, we used global positioning system collars to track wild giant pandas at high resolution (<10 m) and sampled foraging patches for nutritional hierarchical level analysis. We predicted that giant pandas select foraging patches with microhabitat characteristics that decrease energy expenditure during foraging according to optimal search theory. We introduce the concept of nutrient load as the product of local patch nutrient concentration and predicted that relatively efficient nutrients in fluctuating nutritional environments may determine foraging patch selection in giant pandas. This is the first time that microhabitat characteristics, key nutrients and foraging behavior have been studied in combination in giant pandas. We used random forest (RF) and generalized linear mixed-effects models (GLMMs) to infer habitat and nutritional factors that may influence foraging patch selection and utilization. Our results reveal that giant pandas select foraging patches with a topography that likely decreases energy expenditure. Giant pandas also favor protein-rich foraging patches, probably because protein can be digested and assimilated faster than cellulose and this maximizes net energy gains. These data provide a new perspective on foraging patch selection strategies in heterogeneous habitats of diet-specialized species under constant nutritional challenge. Improved conservation planning can be undertaken according to our findings. [ABSTRACT FROM AUTHOR]

We report on the first study to track the spatial behaviors of wild giant pandas ( Ailuropoda melanoleuca) using high-resolution global positioning system (GPS) telemetry. Between 2008 and 2009, 4 pandas (2 male and 2 female) were tracked in Foping Reserve, China for an average of 305 days (± 54.8 SE). Panda home ranges were larger than those of previous very high frequency tracking studies, with a bimodal distribution of space-use and distinct winter and summer centers of activity. Home range sizes were larger in winter than in summer, although there was considerable individual variability. All tracked pandas exhibited individualistic, unoriented and multiphasic movement paths, with a high level of tortuosity within seasonal core habitats and directed, linear, large-scale movements between habitats. Pandas moved from low elevation winter habitats to high elevation (>2000 m) summer habitats in May, when temperatures averaged 17.5 °C (± 0.3 SE), and these large-scale movements took <1 month to complete. The peak in panda mean elevation occurred in Jul, after which they began slow, large-scale movements back to winter habitats that were completed in Nov. An adult female panda made 2 longdistance movements during the mating season. Pandas remain close to rivers and streams during winter, possibly reflecting the elevated water requirements to digest their high-fiber food. Panda movement path tortuosity and first-passage-time as a function of spatial scale indicated a mean peak in habitat search effort and patch use of approximately 700 m. Despite a high degree of spatial overlap between panda home ranges, particularly in winter, we detected neither avoidance nor attraction behavior between conspecifics. [ABSTRACT FROM AUTHOR]

Characteristics of the gut microbiome vary synchronously with changes in host diet. However, the underlying effects of these fluctuations remain unclear. Here, we performed fecal microbiota transplantation (FMT) of diet-specific feces from an endangered mammal (the giant panda) into a germ-free mouse model. We demonstrated that the butyrate-producing bacterium Clostridium butyricum was more abundant during shoot-eating season than during the leaf-eating season, congruent with the significant increase in host body mass. Following season-specific FMT, the microbiota of the mouse model resembled that of the donor, and mice transplanted with the microbiota from the shoot-eating season grew faster and stored more fat. Mechanistic investigations revealed that butyrate extended the upregulation of hepatic circadian gene Per2 , subsequently increasing phospholipid biosynthesis. Validation experiments further confirmed this causal relationship. This study demonstrated that seasonal shifts in the gut microbiome affect growth performance, facilitating a deeper understanding of host-microbe interactions in wild mammals. [Display omitted] • Giant pandas gain more body mass when eating shoots compared with leaves • More SCFAs are produced by the giant panda gut microbiome in the shoot-eating season • GF mice receiving the panda microbiota from the shoot-eating season gain more fat • Butyrate can synchronize host hepatic circadian rhythm to increase lipid production Huang et al. reveal that the gut microbiome can confer a plastic physiological response to seasonal diet shifts in the giant panda via synchronizing host peripheral circadian rhythm. The study sheds light on the causal relationships between the gut microbiome and host phenotype, providing potential avenues to improve host fitness. [ABSTRACT FROM AUTHOR]

Scent marking entails significant energetic and opportunity costs that demand efficiency. Signal detection theory offers a theoretical framework that generates testable hypotheses regarding where animals should place scent signals in the environment in a way that maximizes their probability of detection by target receivers while minimizing costs of production and distribution. Solitary and reliant on chemical communication, the giant panda, Ailuropoda melanoleuca, offers an interesting model to test these ideas. We studied scent-marking patterns in wild giant pandas in the Foping Nature Reserve by surveying areas containing a high density of scent posts. Pandas did not deploy scent marks randomly in this environment, but targeted trees with specific characteristics that promoted signal persistence, range and/or likelihood of detection. Variables affecting selection of scent-marking sites included bark roughnesss, presence of moss on the tree trunk, tree diameter and distance to the trail. That pandas should be efficient with their use of chemosignals comes as no surprise, as mounting evidence is suggesting that many aspects of giant panda life history are constrained by their energetically poor diet. We also found seasonal and sex differences in marking patterns, indicating a role for scent marking in reproduction and competition. Males scent-marked throughout the year, whereas females scent-marked predominantly during the mating season, suggesting functional differences in scent marking between the sexes. [ABSTRACT FROM AUTHOR]

Giant pandas are unusual in belonging to a primarily carnivorous clade and yet being extremely specialized herbivores that feed almost exclusively on highly fibrous bamboo [ 1 ]. Paradoxically, they appear inconsistently adapted to their plant diet, bearing a mix of herbivore and carnivore traits. Herbivore traits include a skull, jaw musculature, and dentition that are adapted for fibrous diets and a specialized "pseudo-thumb" used for handling bamboo [ 2, 3 ]. They have lost functional versions of the T1R1 gene codes for umami taste receptors, which are often associated with meat eating [ 3 ]. They also have an herbivore-like subcellular distribution of the metabolic enzyme alanine: glyoxylate aminotransferase [ 4 ]. But meanwhile, giant pandas have a digestive tract [ 5 ], digestive enzymes [ 6 ], and a gut microbiota composition that resemble those of carnivores and not of herbivores [ 6, 7 ]. We draw on recent developments in multi-dimensional niche theory [ 8 ] to examine this apparent paradox. We show that the pandas' diet clustered in a macronutrient space among carnivores and was distinct from that of herbivores. The similarity with carnivore diets applied not only to the ingested diet but also to the absorbed diet, with the absorbed macronutrient ratios similar to those of the ingested foods. Comparison of the macronutrient composition of pandas' milk with those of other species shows that the carnivore-like dietary macronutrient composition extends across the life cycle. These results cast new light on the seemingly incongruous constellation of dietary adaptations in pandas, suggesting that the transition from carnivorous and omnivorous ancestry to specialized herbivory might be less abrupt than it might otherwise appear. • Giant pandas show seasonal foraging migration associated with bamboo phenology • The macronutrient energy ratios of pandas' diets are similar to those of carnivores • The absorbed macronutrient ratios of pandas are similar to those of the ingested foods • The diet specialization of giant pandas might be less abrupt than it might appear Giant pandas feed on bamboo, yet they have both herbivore and carnivore traits. Nie et al. show that the macronutrient composition of the ingested and absorbed diets resembles the diets of carnivores, not of herbivores. This can explain why pandas have adapted incompletely to the plant diet and suggests that their shift to herbivory was easier than it might otherwise seem. [ABSTRACT FROM AUTHOR]

Abstract As certain extreme weather events are becoming frequent and intense, conservationists must identify areas across species' ranges recurrently affected, especially with regard to threatened species. Focusing on the giant panda (Ailuropoda melanoleuca) and historical flood frequency distribution, we determined overlaps between panda distribution affected by floods and nature reserves. We also examined the correspondence between areas subject to high flood exposure densities, areas with high panda habitat use, and areas that exhibit high human density. Of the 67 reserves established for giant panda conservation 7 included areas with the highest flood exposure densities while having a mean exposure ranging between 20 and 75%. In Sichuan province up to 32% of areas of high habitat use were subject to low flood density, and 10% overlapped with areas subject to high flood density. We also found that 40% of the total area with high human density was subject to a high flood density. Our findings indicate that high frequency of flooding is affecting areas of nature reserves where people are rather than areas which pandas are using more intensively. In areas occupied by pandas, strategies should remain focus on mitigating habitat degradation and fragmentation caused by human activities that can also reduce habitat resilience to floods. Management aimed at reducing vulnerability and enhancing resilience in flood-prone areas is warranted if we are to prevent negative indirect impacts on panda habitat driven by human responses to increasingly frequent and intense extreme weather events in the coming decades. Highlights • Areas inside giant panda nature reserves are highly exposed to floods. • Frequent flooding is affecting areas with people rather than areas used by pandas. • Building resilience is crutial for preventing additional pressures on panda habitat. [ABSTRACT FROM AUTHOR]

Reintroduction is an important approach in the conservation of endangered species and in recent decades a number of reintroduction programs have been conducted for conservation purposes. Generally, the success rate of reintroduction is low, but long-term monitoring of most reintroduction programs remains uncommon and this may influence the evaluation of reintroduction. The giant panda is a flagship species of biodiversity conservation. The Chinese government runs a giant panda reintroduction program and here we present reintroduction monitoring data from 2009 to 2015 for three giant pandas released into a small isolated wild population in western Sichuan, China. The results indicate that all three giant pandas display similar activity patterns to wild giant pandas, however, the wild-caught female demonstrated better adaptive ability to the wild environment than the two captive-born individuals in that she established a stable home range in the quickest time and gave birth to a cub. Genetic analysis indicates that new genetic material has been introduced into the local population. Our study provides the latest update on the giant panda introduction program and indicates that it is progressing well. [ABSTRACT FROM AUTHOR]

Abstract Small features in ecological systems are often underrepresented in conservation monitoring, management and policy. Tree cavities and other forms of refuge play disproportionately large ecological roles due to their importance for shelter and rearing vulnerable offspring. Giant panda (Ailuropoda melanoleuca) cubs are highly altricial, and dependent on dens. In Fengtongzai—a reserve with cavity-containing old growth forest—we measured 19 structural and microhabitat variables in potential tree dens. We also established data loggers in rock cavities in Foping Nature Reserve (which due to logging does not contain old growth) and tree cavities in Fengtongzai to monitor temperature and humidity inside and outside dens to evaluate microclimatic buffering. Fengtongzai pandas selected tree dens that were better concealed, with large interiors and entrances but smaller entrance to interior ratios. Microclimate inside dens differed dramatically from ambient conditions outside: in cold weather dens were warmer, in hot weather dens were cooler, dens were less humid and dens had more stable microclimates. Dens used by maternal pandas were warmer, drier and less variable than tree and rock cavities that were not used. Tree dens showed better capacity to buffer against extremes of temperature and humidity than did cave dens. Our findings have important conservation implications, including the value of den sites and the need for better monitoring and management. Specifically, management practices that preserve large old trees may increase carrying capacity and any experimentation with artificial dens as a conservation intervention should reference our findings on structural and microclimatic characteristics of preferred den sites. [ABSTRACT FROM AUTHOR]

Summary The ancestral panda Ailurarctos lufengensis , excavated from the late Miocene, is thought to be carnivorous or omnivorous [ 1 ]. Today, giant pandas exclusively consume bamboo and have distinctive tooth, skull, and muscle characteristics adapted to a tough and fibrous bamboo diet during their long evolution [ 1, 2 ]. A special feature, the pseudo-thumb, has evolved to permit the precise and efficient grasping of bamboo [ 3, 4 ]. Unlike those of extant pandas, little is known about the diet and habitat preferences of extinct pandas. Prevailing studies suggest that the panda shifted to specialized bamboo feeding in the Pleistocene [ 5, 6 ]; however, this remains questionable. Pandas now survive in a fraction of their historical habitat [ 7 ], but no specific information has been reported. Stable isotope analyses can be used to understand diet- and habitat-related changes in animals [ 8 ]. Isotopic signals in bone collagen reflect dietary compositions of ancient human diets [ 9, 10 ] and dietary changes between historical and modern animal populations [ 11, 12 ]. Here, we conduct stable isotope analyses of bone and tooth samples from ancient and modern pandas and from sympatric fauna. We show that pandas have had a diet dominated by C 3 resources over time and space and that trophic niches of ancient and modern pandas are distinctly different. The isotopic trophic and ecological niche widths of ancient pandas are approximately three times larger than those of modern pandas, suggesting that ancient pandas possibly had more complex diets and habitats than do their modern counterparts. Our findings provide insight into the dietary evolution and habitat contraction of pandas. Highlights • We determine stable isotope values of ancient and modern pandas and sympatric species • The isotopic trophic niches of ancient and modern pandas are distinctly different • The niche widths of ancient pandas are about 3× larger than those of modern pandas • The diet specialization of pandas was probably unfinished at the mid-Holocene Han et al. compare stable isotope ratios from the bones and teeth of extant and extinct pandas and show that their trophic niches are distinctly different, although both species had a C 3 -dominated diet over time and space. The results indicate that ancient pandas possibly had more complex diets and habitats than do their modern counterparts. [ABSTRACT FROM AUTHOR]

Summary Ecosystem services (the benefits to humans from ecosystems) are estimated globally at $125 trillion/year [ 1, 2 ]. Similar assessments at national and regional scales show how these services support our lives [ 3 ]. All valuations recognize the role of biodiversity, which continues to decrease around the world in maintaining these services [ 4, 5 ]. The giant panda epitomizes the flagship species [ 6 ]. Its unrivalled public appeal translates into support for conservation funding and policy, including a tax on foreign visitors to support its conservation [ 7 ]. The Chinese government has established a panda reserve system, which today numbers 67 reserves [ 8, 9 ]. The biodiversity of these reserves is among the highest in the temperate world [ 10 ], covering many of China’s endemic species [ 11 ]. The panda is thus also an umbrella species [ 12 ]—protecting panda habitat also protects other species. Despite the benefits derived from pandas, some journalists have suggested that it would be best to let the panda go extinct. With the recent downlisting of the panda from Endangered to Vulnerable, it is clear that society’s investment has started to pay off in terms of panda population recovery [ 13, 14 ]. Here, we estimate the value of ecosystem services of the panda and its reserves at between US$2.6 and US$6.9 billion/year in 2010. Protecting the panda as an umbrella species and the habitat that supports it yields roughly 10–27 times the cost of maintaining the current reserves, potentially further motivating expansion of the reserves and other investments in natural capital in China. [ABSTRACT FROM AUTHOR]

Climate and land-use changes are predicted to impact biodiversity, threatening ecosystem services and functions. However, their combined effects on the functional diversity of mammals at the regional scale remain unclear, especially at the beta level. Here, we use projected climate and land-use changes in China to investigate their potential effects on the alpha and beta functional diversities of terrestrial mammals under low- and high-emission scenarios. In the current projection, we showed strong positive spatial correlations between functional richness and species richness. Functional evenness (FEve), functional specialization (FSpe), and functional originality (FOri) decreased with species richness, and functional divergence (FDiv) increased first and then plateaued. Functional beta diversity was dominated by its nestedness component, in contrast to the taxonomic facet. Potential changes in species richness are more strongly influenced by land-use change under the low-emission scenario, while under the high-emission scenario, they are more strongly influenced by climate change. Changes in functional richness (FRic) were inconsistent with those in species richness, with a magnitude of decreases greater than predicted from species richness. Moreover, mammal assemblages showed potential functional differentiation (FD) across the country, and the trends exceeded those towards taxonomic differentiation (TD). Our findings help us understand the processes underlying biodiversity responses to global changes on multiple facets and provide new insight for conservation plans., (© 2024. Science China Press.)

Brown-and-white giant pandas (hereafter brown pandas) are distinct coat color mutants found exclusively in the Qinling Mountains, Shaanxi, China. However, its genetic mechanism has remained unclear since their discovery in 1985. Here, we identified the genetic basis for this coat color variation using a combination of field ecological data, population genomic data, and a CRISPR-Cas9 knockout mouse model. We de novo assembled a long-read-based giant panda genome and resequenced the genomes of 35 giant pandas, including two brown pandas and two family trios associated with a brown panda. We identified a homozygous 25-bp deletion in the first exon of Bace2 , a gene encoding amyloid precursor protein cleaving enzyme, as the most likely genetic basis for brown-and-white coat color. This deletion was further validated using PCR and Sanger sequencing of another 192 black giant pandas and CRISPR-Cas9 edited knockout mice. Our investigation revealed that this mutation reduced the number and size of melanosomes of the hairs in knockout mice and possibly in the brown panda, further leading to the hypopigmentation. These findings provide unique insights into the genetic basis of coat color variation in wild animals., Competing Interests: Competing interests statement:The authors declare no competing interest.

The giant panda ( Ailuropoda melanoleuca ) is an iconic bear native to China, famous for eating almost exclusively bamboo. This unusual dietary behavior for a carnivore is enabled by several key adaptations including low physical activity, reduced organ sizes and hypothyroidism leading to lowered energy expenditure. These adaptive phenotypes have been hypothesized to arise from a panda-unique single-nucleotide mutation in the dual-oxidase 2 ( DUOX2 ) gene, involved in thyroid hormone synthesis. To test this hypothesis, we created genome-edited mice carrying the same point mutation as the panda and investigated its effect on metabolic phenotype. Homozygous mice were 27% smaller than heterozygous and wild-type ones, had 13% lower body mass-adjusted food intake, 55% decreased physical activity, lower mass of kidneys (11%) and brain (5%), lower serum thyroxine (T4: 36%), decreased absolute (12%) and mass-adjusted (5%) daily energy expenditure, and altered gut microbiota. Supplementation with T4 reversed the effects of the mutation. This work uses a state-of-the-art genome editing approach to demonstrate the link between a single-nucleotide mutation in a key endocrine-related gene and profound adaptive changes in the metabolic phenotype, with great importance in ecology and evolution., (© The Author(s) 2021. Published by Oxford University Press on behalf of China Science Publishing & Media Ltd.)

Conservation genetics and genomics are two independent disciplines that focus on using new techniques in genetics and genomics to solve problems in conservation biology. During the past two decades, conservation genetics and genomics have experienced rapid progress. Here, we summarize the research advances in the conservation genetics and genomics of threatened vertebrates (e.g., carnivorans, primates, ungulates, cetaceans, avians, amphibians and reptiles) in China. First, we introduce the concepts of conservation genetics and genomics and their development. Second, we review the recent advances in conservation genetics research, including noninvasive genetics and landscape genetics. Third, we summarize the progress in conservation genomics research, which mainly focuses on resolving genetic problems relevant to conservation such as genetic diversity, genetic structure, demographic history, and genomic evolution and adaptation. Finally, we discuss the future directions of conservation genetics and genomics., (Copyright © 2018 Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, and Genetics Society of China. Published by Elsevier Ltd. All rights reserved.)