The inevitable impacts of climate change have reverberated across ecosystems and caused substantial global biodiversity loss. Climate-induced habitat loss has contributed to range shifts at both species and community levels. Given the importance of identifying suitable habitats for at-risk species, it is imperative to assess potential current and future distributions, and to understand influential environmental factors. Like many species, the Demoiselle crane is not immune to climatic pressures. Khyber Pakhtunkhwa and Balochistan provinces in Pakistan are known wintering grounds for this species. Given that Pakistan is among the top five countries facing devastating effects of climate change, this study sought to conduct species distribution modeling under climate change using data collected during 4 years of field surveys. We developed a Maximum Entropy distribution model to predict the current and projected future distribution of the species across the study area. Future habitat projections for 2050 and 2070 were carried out using two representative concentration pathways (RCP 4.5 and RCP 8.5) under three global circulation models, including HADGEM2-AO, BCC-CSM1-1, and CCSM4. The most influential factors shaping Demoiselle Crane habitat suitability included the temperature seasonality, annual mean temperature, terrain ruggedness index, and human population density, all of which contributed significantly to the suitability (81.3%). The model identified 35% of the study area as moderately suitable (134,068 km2) and highly suitable (27,911 km2) habitat for the species under current climatic conditions. Under changing climate scenarios, our model predicted a major loss of the species' current suitable habitat, with shrinkage and shift towards western-central areas along the Pakistan-Afghanistan boarder. The RCP 8.5, which is the extreme climate change scenario, portrays particularly severe consequences, with habitat losses reaching 65% in 2050 and 85% in 2070. This comprehensive study provides useful insights into the Demoiselle Crane habitat's current and future dynamics in Pakistan.
Population abundance and density estimates play important roles in biodiversity conservation assessment and can lead to prioritization of conservation efforts, strategies, and management. The Calabar angwantibo (Arctocebus calabarensis) is a poorly studied, Near-Threatened nocturnal, arboreal mammal species occurring only in the lowland moist tropical rainforest blocks of southeastern Nigeria and southwestern Cameroon. Like other arboreal nocturnal mammals, there are gaps in knowledge of the distribution and abundance of this species, which may be facing population declines due to habitat loss and hunting. In this study, we investigated the abundance and density of A. calabarensis in the Oban Hills Region of Nigeria. We conducted systematic distance sampling survey along 32 transects in different habitats in a 1227 km of survey efforts. A total of 41 sightings of A. calabarensis were detected, resulting in an abundance of 7345 individuals (95% CI = 1.51-4.37) with an estimated density of 2.57 animals/km2. The estimated population abundance is 6515 individuals in closed-canopy forests and 830 individuals in secondary forests, with encounter rates of 0.52 individual/km2 and 0.60 individuals/km2 in the closed canopy and secondary forest habitats. The global estimates encounter rate of A. calabarensis across the habitat types is 0.33 individuals/km2 and population abundance of 4456 individuals. Our findings indicate that the A. calabarensis populations can adapt to low changes in forest habitat modifications resulting from increasing and widespread forest disturbance by human-dominated activity, which is giving way to forest clearance for agriculture cultivation and infrastructural development. Our findings help to fill a knowledge gap regarding this species and may help establish a baseline for future management, population monitoring, and conservation of the cryptic population of A. calabarensis in Cross-Sanaga Forests.
Geographical background and dispersal ability may strongly influence assemblage dissimilarity; however, these aspects have generally been overlooked in previous large-scale beta diversity studies. Here, we examined whether the patterns and drivers of taxonomic beta diversity (TBD) and phylogenetic beta diversity (PBD) of breeding birds in China vary across (1) regions on both sides of the Hu Line, which demarcates China's topographical, climatic, economic, and social patterns, and (2) species with different dispersal ability. TBD and PBD were calculated and partitioned into turnover and nestedness components using a moving window approach. Variables representing climate, habitat heterogeneity, and habitat quality were employed to evaluate the effects of environmental filtering. Spatial distance was considered to assess the impact of dispersal limitation. Variance partitioning analysis was applied to assess the relative roles of these variables. In general, the values of TBD and PBD were high in mountainous areas and were largely determined by environmental filtering. However, different dominant environmental filters on either side of the Hu Line led to divergent beta diversity patterns. Specifically, climate-driven species turnover and habitat heterogeneity-related species nestedness dominated the regions east and west of the line, respectively. Additionally, bird species with stronger dispersal ability were more susceptible to environmental filtering, resulting in more homogeneous assemblages. Our results indicated that regions with distinctive geographical backgrounds may present different ecological factors that lead to divergent assemblage dissimilarity patterns, and dispersal ability determines the response of assemblages to these ecological factors. Identifying a single universal explanation for the observed pattern without considering these aspects may lead to simplistic or incomplete conclusions. Consequently, a comprehensive understanding of large-scale beta diversity patterns and effective planning of conservation strategies necessitate the consideration of both geographical background and species dispersal ability.
Biodiversity , Ecosystem , Animals , Phylogeny , China , Birds/genetics
Himalayan musk deer (Moschus leucogaster) is classified as an endangered species by IUCN with a historically misunderstood distribution due to misidentification with other species of musk deer, Moschus spp. Taking advantage of recent genetic analyses confirming the species of various populations in Nepal and China, we produced an accurate estimate of the species' current and future distribution under multiple climate change scenarios. We collected high-quality occurrence data using systematic surveys of various protected areas of Nepal to train species distribution models. The most influential determinants of the distribution of Himalayan musk deer were precipitation of the driest quarter, temperature seasonality, and annual mean temperature. These variables, and precipitation in particular, determine the vegetation type and structure in the Himalaya, which is strongly correlated with the distribution of Himalayan musk deer. We predicted suitable habitats between the Annapurna and Kanchenjunga region of Nepal Himalaya as well as the adjacent Himalaya in China. Under multiple climate change scenarios, the vast majority (85-89%) of current suitable sites are likely to remain suitable and many new areas of suitable habitat may emerge to the west and north of the current species range in Nepal and China. Two-thirds of current and one-third of future suitable habitats are protected by the extensive network of protected areas in Nepal. The projected large gains in suitable sites may lead to population expansion and conservation gains, only when the threat of overexploitation and population decline is under control.
Deer , Animals , Deer/genetics , Ruminants , Endangered Species , Ecosystem , China , Climate Change
Farnesoid X receptor (FXR) is widely accepted as a promising target for various liver diseases; however, panels of ligands in drug development show limited clinical benefits, without a clear mechanism. Here, we reveal that acetylation initiates and orchestrates FXR nucleocytoplasmic shuttling and then enhances degradation by the cytosolic E3 ligase CHIP under conditions of liver injury, which represents the major culprit that limits the clinical benefits of FXR agonists against liver diseases. Upon inflammatory and apoptotic stimulation, enhanced FXR acetylation at K217, closed to the nuclear location signal, blocks its recognition by importin KPNA3, thereby preventing its nuclear import. Concomitantly, reduced phosphorylation at T442 within the nuclear export signals promotes its recognition by exportin CRM1, and thereby facilitating FXR export to the cytosol. Acetylation governs nucleocytoplasmic shuttling of FXR, resulting in enhanced cytosolic retention of FXR that is amenable to degradation by CHIP. SIRT1 activators reduce FXR acetylation and prevent its cytosolic degradation. More importantly, SIRT1 activators synergize with FXR agonists in combating acute and chronic liver injuries. In conclusion, these findings innovate a promising strategy to develop therapeutics against liver diseases by combining SIRT1 activators and FXR agonists.
Elusive species often use latrines which also serves as communication and information hubs. Thus, studying behavior at latrines may provide critical insights into the species' ecology and behavior. While it is established that musk deer use latrines for defecating, very little is known about the endangered Himalayan musk deer (Moschus leucogaster) and their latrines. We examined musk deer behavior from the various video clips lasting 238 min altogether, captured at latrine sites during both breeding and non-breeding seasons in the Annapurna Conservation Area of Nepal. A total of 428 visits by musk deer and 479 behavioral events by them were captured. We constructed an ethogram to describe musk deer behavior and compared behavior across individuals and sex using parametric and non-parametric tests. We found that musk deer are crepuscular and nocturnal animals. Both male and female musk deer repeatedly and independently visited shared latrine sites as well as exclusively used latrine sites. The proportion of male musk deer visited latrine sites were significantly higher than that of female musk deer. Hence, male musk deer were found more active (>2 times) than females during both seasons. The most frequently observed behavioral activities at the latrine sites were defecating, sniffing and browsing, followed by scrapping and covering, and ignoring the latrine sites. The defecating and sniffing activity were performed throughout breeding and non-breeding seasons to establish communication among peers and to claim territory. Based on the behaviors observed at the latrine sites, we can presume that Himalayan musk deer likely use latrines to convey various messages, including personality, maturity, sexual status, and territory marking among conspecifics. These findings of this study can be used for the conservation of musk deer in its natural habitat and replicated in captivity to enhance breeding performance that improves long-term conservation prospects for this species.
Cancer remains the primary cause of death worldwide. To develop less toxic anti-cancer drugs to relieve the suffering and improve the survival of cancer patients is the major focus in the anti-cancer field. To this end, marine creatures are being extensively studied for their anti-cancer effects, since extracts from at least 10% of the marine organisms have been shown to possess anti-tumor activities. As a classic Chinese traditional medicine, sea cucumbers and compounds extracted from the sea cucumbers, such as polysaccharides and saponins, have recently been shown to exhibit anti-cancer, anti-inflammatory, and anti-oxidant effects. Holothuria leucospilota (H. leucospilota) is a tropical edible sea cucumber species that has been successfully cultivated and farmed in large scales, providing a readily available source of raw materials to support the development of novel marine anti-cancer drugs. However, very few studies have so far been performed on the biological activities of H. leucospilota. In this study, we first investigated the anti-cancer effect of H. leucospilota protein on three cancer cell lines (i.e., HepG2, A549, Panc02) and three normal cell lines (NIH-3T3, HaCaT, 16HBE). Our data showed that H. leucospilota protein decreased the cell viabilities of HepG2, A549, HaCaT, 16HBE in a concentration-dependent manner, while Panc02 and NIH-3T3 in a time- and concentration-dependent manner. We also found that the inhibitory effect of H. leucospilota protein (≥10 µg/mL) on cell viability is near or even superior to EPI, a clinical chemotherapeutic agent. In addition, our data also demonstrated that H. leucospilota protein significantly affected the cell cycle and induced apoptosis in the three cancer cell lines investigated; in comparison, it showed no effects on the normal cell lines (i.e., NIH-3T3, HaCaT and 16HBE). Finally, our results also showed that H. leucospilota protein exhibited the excellent performance in inhibiting cell immigrations. In conclusion, H. leucospilota protein targeted the cancer cell cycles and induced cancer cell apoptosis; its superiority to inhibit cancer cell migration compared with EPI, shows the potential as a promising anti-cancer drug.
Antineoplastic Agents , Holothuria , Neoplasms , Saponins , Sea Cucumbers , Animals , Antineoplastic Agents/pharmacology , Antioxidants , Humans , Neoplasms/drug therapy
Describing the patterns and revealing the underlying mechanisms responsible for variations in community structure remain a central focus in ecology. However, important gaps remain, including our understanding of species abundance. Most studies on abundance-based relationships are from either temperate ecosystems or tropical ecosystems, and few have explicitly tested abundance-based relationships across a temperate to tropical ecotone. Here, we use a comprehensive dataset of breeding birds across elevation spanning a temperate to subtropical gradient in the Himalayas-Hengduan Mountains of China to examine the relationship between species abundance and (a) elevational range size, (b) body size, (c) elevational range centre and (d) endemicity. We tested a priori predictions for abundance-elevational range size relationship, abundance-body size relationship and abundance-elevational range centre relationship, and explored how these relationships change along this temperate to subtropical mountain ecosystem. We found that species abundance was significantly positively correlated with elevational range size across the study sites, demonstrating the key importance of elevational range size towards species abundance. Body size and elevational range centre are weakly correlated with abundance. A novel finding of our study is that the abundance-elevational range size relationship gradually weakened from temperate to subtropical ecosystems, adding to a growing body of evidence suggesting that abundance-elevational range size tracks a temperate to tropical ecotone. Our study demonstrates that abundance range-size relationship can transition across ecotones where faunas of different evolutionary origins converge. Furthermore, measuring abundance relationships across different environmental variables at the same spatial scale with comparable biogeography is a key strategy that can reveal the underlying mechanisms behind abundance patterns.
Biodiversity , Ecosystem , Altitude , Animals , Biological Evolution , Birds
Mercury (Hg), as a global pollutant, its contamination has been documented in environmental compartments of the Himalayan region. However, little research exists regarding to Hg accumulation in terrestrial wildlife, as well as its driving factors. In this study, surface soil and small mammals were collected in the Lebu Valley, East Himalayas of China, in order to measure the uptake of the long-distance transported Hg along an elevational gradient approximately from 2300 to 5000 m a.s.l. The soil Hg concentrations were measured and predicted mostly by vegetation type as well as soil organic matter, while the Hg in hair of small mammals (Muridae and Cricetidae) showed deeply influenced by soil Hg. Notably, combined with the field survey data, soil and hair Hg were both enhanced in low and mid-elevations, which overlapped the distribution ranges of a majority of mammals. Overall, this indicates that Hg contamination in low- and mid-elevations poses a potential threat to the top predators that consuming small mammals directly or indirectly. Furthermore, our data advances the understanding of Hg dynamics in remote, high mountain ecosystems and provides baseline data for biomonitoring for reduction of Hg emission globally.
Mercury , Soil Pollutants , Animals , Ecosystem , Environmental Monitoring , Mammals , Mercury/analysis , Soil , Soil Pollutants/analysis
A fundamental yet controversial topic in biogeography is how and why species range sizes vary along spatial gradients. To advance our understanding of these questions and to provide insights into biological conservation, we assessed elevational variations in the range sizes of vascular plants with different life forms and biogeographical affinities and explored the main drivers underlying these variations in the longest valley in China's Himalayas, the Gyirong Valley. Elevational range sizes of vascular plants were documented in 96 sampling plots along an elevational gradient ranging from 1,800 to 5,400 m above sea level. We assessed the elevational variations in range size by averaging the range sizes of all recorded species within each sampling plot. We then related the range size to climate, disturbance, and the mid-domain effect and explored the relative importance of these factors in explaining the range size variations using the Random Forest model. A total of 545 vascular plants were recorded in the sampling plots along the elevational gradient. Of these, 158, 387, 337, and 112 were woody, herbaceous, temperate, and tropical species, respectively. The range size of each group of vascular plants exhibited uniform increasing trends along the elevational gradient, which was consistent with the prediction of Rapoport's rule. Climate was the main driver of the increasing trends of vascular plant range sizes in the Gyirong Valley. The climate variability hypothesis and mean climate condition hypothesis could both explain the elevation-range size relationships. Our results reinforce the previous notion that Rapoport's rule applies to regions where the influence of climate is the most pronounced, and call for close attention to the impact of climate change to prevent species range contraction and even extinction due to global warming.
Cadmium-contaminated wastewater has attracted increasing concerns due to its non-biodegradable properties and high toxicity. To explore eco-friendly and economically feasible strategies, the screened Alcaligenes faecalis K2 were employed for the biomineralization and recovery of Cd2+ from wastewater while producing considerable secretory organo-biominerals (SOBs) as bioadsorbents. At 75 mg/L Cd2+ exposure, 85.5% of Cd2+ was removed by K2, 43.0% of which was fixed in the granular SOBs. SOBs were convenient for separating from the solution. The adsorption capacity of granular sorbent made from SOBs was verified to be greater than 77.1 mg/g. Practically, 89.5% of 75 mg/L of Cd2+ could be stably removed while ereK2 continuously generated SOBs in a moving-bed biofilm reactor (MBBR). To sum up, the production of bioadsorbents can be achieved by K2, while removing Cd with live microorganisms, which was conducive to making full use of materials and improving Cd removal efficiency.
Alcaligenes faecalis , Water Pollutants, Chemical , Adsorption , Biofilms , Biomineralization , Bioreactors , Cadmium/analysis , Water Pollutants, Chemical/analysis
The global escalation and intensification of cyanobacterial blooms require powerful algaecides. This study investigated the algicidal efficacy and mechanism of EA-1 against Oscillatoria. Bacteria EA-1, identified as Enterobacter, was isolated with high algicidal activity against harmful cyanobacteria. Results showed that a complete removal of Oscillatoria was observed within 3 days with the initial Chl-a concentration of 1.74 mg/L. Physiological responses of Oscillatoria revealed that EA-1 induced severe lipid peroxidation and the ultimate decline of antioxidant enzyme activities. Moreover, the contents for both intracellular protein and carbohydrate of each algae cell increased first and then decreased. Scanning electron microscope (SEM) and transmission electron microscopy (TEM) analysis clarified that the possible process of Oscillatoria lysis included the breach of cross wall, followed by the disruption of photosynthetic membrane and incipient nucleus, and the ultimate outflow of inclusion. Confocal laser scanning microscopy (CLSM) analysis illustrated the degradation process of incipient nucleus in Oscillatoria.
Cyanobacteria , Oscillatoria , Antioxidants , Aquaculture , Enterobacter
Previous work based on molecular evidence has shown that most socially monogamous birds follow a genetic polyandrous mating system. However, our knowledge about avian mating systems is heavily biased toward the north temperate zone, with data on tropical birds remaining relatively scarce. This uneven distribution of both phylogenetic and spatial sampling has hampered our understanding and interpretation of results. In this study, we investigated the frequency of extra-pair paternity (EPP) in a tropical population of yellow-bellied prinias ( Prinia flaviventris) in Guangxi, southern China. A total of 129 individuals belonging to 24 nests were sampled, among which 12 out of 83 chicks (14.46%) in seven nests were found to be EPP offspring. In nests in which all nestlings were sampled, only five out of 56 chicks were EPP offspring, accounting for an unbiased EPP rate of 8.93%. This rate is below the average rate of EPP in the family Sylviidae. The possible causes of EPP in prinias and the occurrence of EPP in birds with high resource investment and intensive parental care are discussed. This study highlights the value of genome-wide markers in determining relatedness in a wild bird species without a reference genome.
Passeriformes/genetics , Passeriformes/physiology , Sexual Behavior, Animal/physiology , Animals , China , Female , Male , Polymorphism, Single Nucleotide
An amendment to this paper has been published and can be accessed via a link at the top of the paper.
Kashmir musk deer Moschus cupreus (KMD) are the least studied species of musk deer. We compiled genetically validated occurrence records of KMD to construct species distribution models using Maximum Entropy. We show that the distribution of KMD is limited between central Nepal on the east and north-east Afghanistan on the west and is primarily determined by precipitation of driest quarter, annual mean temperature, water vapor, and precipitation during the coldest quarter. Precipitation being the most influential determinant of distribution suggests the importance of pre-monsoon moisture for growth of the dominant vegetation, Himalayan birch Betula utilis and Himalayan fir Abies spectabilis, in KMD's preferred forests. All four Representative Concentration Pathway Scenarios result an expansion of suitable habitat in Uttarakhand, India, west Nepal and their associated areas in China in 2050s and 2070s but a dramatic loss of suitable habitat elsewhere (Kashmir region and Pakistan-Afghanistan border). About 1/4th of the current habitat will remain as climate refugia in future. Since the existing network of protected areas will only include a tiny fraction (4%) of the climatic refugia of KMD, the fate of the species will be determined by the interplay of more urgent short-term forces of poaching and habitat degradation and long-term forces of climate change.
Deer , Demography , Afghanistan , Animals , China , Climate Change , Conservation of Natural Resources/methods , Ecological Parameter Monitoring/methods , Ecosystem , Endangered Species/trends , Forests , India , Nepal , Pakistan , Population Density , Refugium
Although elevational patterns of species richness have been well documented, how the drivers of richness gradients vary across ecological guilds has rarely been reported. Here, we examined the effects of spatial factors (area and mid-domain effect; MDE) and environmental factors, including metrics of climate, productivity, and plant species richness on the richness of breeding birds across different ecological guilds defined by diet and foraging strategy. We surveyed 12 elevation bands at intervals of 300 m between 1,800 and 5,400 m a.s.l using line-transect methods throughout the wet season in the central Himalaya, China. Multiple regression models and hierarchical partitioning were used to assess the relative importance of spatial and environmental factors on overall bird richness and guild richness (i.e., the richness of species within each guild). Our results showed that richness for all birds and most guilds displayed hump-shaped elevational trends, which peaked at an elevation of 3,300-3,600 m, although richness of ground-feeding birds peaked at a higher elevation band (4,200-4,500 m). The Normalized Difference Vegetation Index (NDVI)-an index of primary productivity-and habitat heterogeneity were important factors in explaining overall bird richness as well as that of insectivores and omnivores, with geometric constraints (i.e., the MDE) of secondary importance. Granivore richness was not related to primary production but rather to open habitats (granivores were negatively influenced by habitat heterogeneity), where seeds might be abundant. Our findings provide direct evidence that the richness-environment relationship is often guild-specific. Taken together, our study highlights the importance of considering how the effects of environmental and spatial factors on patterns of species richness may differ across ecological guilds, potentially leading to a deeper understanding of elevational diversity gradients and their implications for biodiversity conservation.
Beta diversity patterns along elevational gradients have become a hot topic in the study of biogeography and can help illuminate the processes structuring mountain ecosystems. Although elevational species richness patterns have been well documented, there remains much uncertainty over the causes of beta diversity patterns across elevational gradients. We conducted bird surveys and obtained high-resolution climatic data along an elevational gradient in Gyirong Valley in the central Himalayas, China, between 1,800 and 5,400 m elevation. In total, we recorded 182 bird species (including 169 breeding birds). We simulated beta diversity patterns with the mid-domain effect (MDE) null model and conducted distance-based redundancy analyses (db-RDA) to relate beta diversity to dispersal limitations, spatial constraints, habitat complexity, contemporary climate, and historical climate. Mantel tests and variation partitioning were employed to identify the magnitude of independent statistical associations of environmental factors with beta diversity. Patterns of empirical and simulated beta diversity were both hump-shaped, peaking at intermediate elevations. The db-RDA indicated that beta diversity was correlated with changes in spatially structured environmental factors, especially with contemporary climate and habitat complexity. Mantel tests and variation partitioning also suggested that climate dissimilarity was the major independent correlate of beta diversity. The random community structure and spatial constraints may also contribute to the overall hump-shaped pattern. Beta diversity of bird communities in Gyirong Valley could be explained by the combination of different factors but is mainly shaped by the spatially structured environmental factors, especially contemporary climate.
The distribution of the capped langur (Trachypithecus pileatus) in China has become controversial since Shortridge's langur (Trachypithecus shortridgei) was upgraded to a full species. The capped langur is considered to be distributed in northeast India, Bangladesh, Bhutan, and northwest Myanmar only (Brandon-Jones et al., 2004; Choudhury, 2008, 2014; Das et al., 2008; Groves, 2001). In our field survey, however, we obtained photos of the capped langur, demonstrating its existence in China.
Animal Distribution , Cercopithecidae/anatomy & histology , Cercopithecidae/physiology , Animals , China
This study examines the relative importance of six variables: area, the mid-domain effect, temperature, precipitation, productivity, and habitat heterogeneity on elevational patterns of species richness for breeding birds along a central Himalaya gradient in the Gyirong Valley, the longest of five canyons in the Mount Qomolangma National Nature Reserve. We conducted field surveys in each of twelve elevational bands of 300 m between 1,800 and 5,400 m asl four times throughout the entire wet season. A total of 169 breeding bird species were recorded and most of the species (74%) were small-ranged. The species richness patterns of overall, large-ranged and small-ranged birds were all hump-shaped, but with peaks at different elevations. Large-ranged species and small-ranged species contributed equally to the overall richness pattern. Based on the bivariate and multiple regression analyses, area and precipitation were not crucial factors in determining the species richness along this gradient. The mid-domain effect played an important role in shaping the richness pattern of large-ranged species. Temperature was negatively correlated with overall and large-ranged species but positively correlated with small-ranged species. Productivity was a strong explanatory factor among all the bird groups, and habitat heterogeneity played an important role in shaping the elevational richness patterns of overall and small-ranged species. Our results highlight the need to conserve primary forest and intact habitat in this area. Furthermore, we need to increase conservation efforts in this montane biodiversity hotspot in light of increasing anthropogenic activities and land use pressure.
