The collection and annotation of lar ge-scale bird datasets are resource-intensive and time-consuming processes that significantly limit the scalability and accuracy of biodiversity monitoring systems.While self-super...The collection and annotation of lar ge-scale bird datasets are resource-intensive and time-consuming processes that significantly limit the scalability and accuracy of biodiversity monitoring systems.While self-supervised learning(SSL)has emerged as a promising approach for leveraging unannotated data,current SSL methods face two critical challenges in bird species recognition:(1)long-tailed data distributions that result in poor performance on underrepresented species;and(2)domain shift issues caused by data augmentation strategies designed to mitigate class imbalance.Here we present SDNet,a novel SSL-based bird recognition framework that integrates diffusion models with large language models(LLMs)to overcome these limitations.SDNet employs LLMs to generate semantically rich textual descriptions for tail-class species by prompting the models with species taxonomy,morphological attributes,and habitat information,producing detailed natural language priors that capture fine-grained visual characteristics(e.g.,plumage patterns,body proportions,and distinctive markings).These textual descriptions are subsequently used by a conditional diffusion model to synthesize new bird image samples through cross-attention mechanisms that fuse textual embeddings with intermediate visual feature representations during the denoising process,ensuring generated images preserve species-specific morphological details while maintaining photorealistic quality.Additionally,we incorporate a Swin Transformer as the feature extraction backbone whose hierarchical window-based attention mechanism and shifted windowing scheme enable multi-scale local feature extraction that proves particularly effective at capturing finegrained discriminative patterns(such as beak shape and feather texture)while mitigating domain shift between synthetic and original images through consistent feature representations across both data sources.SDNet is validated on both a self-constructed dataset(Bird_BXS)an d a publicly available benchmark(Birds_25),demonstrating substantial improvements over conventional SSL approaches.Our results indicate that the synergistic integration of LLMs,diffusion models,and the Swin Transformer architecture contributes significantly to recognition accuracy,particularly for rare and morphologically similar species.These findings highlight the potential of SDNet for addressing fundamental limitations of existing SSL methods in avian recognition tasks and establishing a new paradigm for efficient self-supervised learning in large-scale ornithological vision applications.展开更多
Catalpa bungei,a fast-growing timber tree,is threatened by the lepidopteran pest Omphisa plagialis.Previous studies in our laboratory successfully generated transgenic C.bungei lines overexpressing Cry genes(Cry1Ab,Cr...Catalpa bungei,a fast-growing timber tree,is threatened by the lepidopteran pest Omphisa plagialis.Previous studies in our laboratory successfully generated transgenic C.bungei lines overexpressing Cry genes(Cry1Ab,Cry2A,and Cry9-2)that exhibited resistance to O.plagialis,but their potential impact on soil bacterial communities remains unclear.In this study,we analyzed nine transgenic C.bungei lines(three independent lines for each Cry gene)to characterize their rhizosphere bacterial communities using high-throughput sequencing of the 16S ribosomal DNA(rDNA)V4-V5 regions.A total of 628 amplicon sequence variants(ASVs)were shared among all transgenic and wild-type(WT)lines,forming a stable core microbiome dominated by Proteobacteria,Bacteroidota,Acidobacteriota,and Actinobacteriota.Alpha diversity showed no significant differences,while beta diversity revealed minor but distinct compositional shifts.Cry1Ab lines exhibited higher abundances of fast-growing taxa,particularly Proteobacteria and Bacteroidota;Cry2A lines displayed intermediate profiles,whereas Cry9-2 lines were nearly indistinguishable from WT communities.Linear discriminant analysis of the effect size revealed significant enrichment of taxa such as Burkholderiaceae and Ralstonia in the Cry1Ab rhizosphere,in contrast to the higher abundance of Chloroflexi in the WT.Functional predictions indicated consistent metabolic pathways across all treatments,suggesting strong ecological redundancy.This study demonstrates minimal impact on rhizosphere microbial communities in transgenic C.bungei plants.The Cry9-2 construct exhibited superior environmental stability,whereas the Cry1Ab construct caused only slight but ecologically acceptable shifts.These findings support the ecological safety of Bt-transgenic C.bungei and identify Cry9-2 as a particularly favorable candidate for forestry applications.This comparative evaluation of three Cry genes in a tree species provides a framework for future gene-specific biosafety assessments in woody plants.展开更多
The survival of ectotherms worldwide is threatened by climate change.Whether increasing temperatures increase the vulnerability of ectotherms inhabiting temperate plateau areas remains unclear.To understand altitudina...The survival of ectotherms worldwide is threatened by climate change.Whether increasing temperatures increase the vulnerability of ectotherms inhabiting temperate plateau areas remains unclear.To understand altitudinal variation in the vulnerability of plateau ectotherms to climate warming,Qinghai toad-headed lizards(Phrynocephalus vlangalii)were subjected to semi-natural enclosure experiments with simulated warming at high(2,600 m)and superhigh(3,600 m)elevations of the Dangjin Mountain,China.Our results revealed that the thermoregulatory effectiveness and warming tolerance(WT)of the toad-headed lizards were significantly affected by climate warming at both elevations,but their thermal sensitivity remained unchanged.After warming,the thermoregulatory effectiveness of lizards at superhigh elevations decreased because of the improved environmental thermal quality,whereas that of lizards at high-elevation conditions increased.Although the body temperature selected by high-elevation lizards was also significantly increased,the proportion of their active body temperature falling within the set-point temperature range decreased.This indicates that it is difficult for high-elevation lizards to adjust their body temperatures within a comfortable range under climate warming.Variations in the WT and thermal safety margin(TSM)under climate warming revealed that lizards at the superhigh elevation benefited from improved environmental thermal quality,whereas those at the high elevation originally on the edge of the TSM faced more severe threats and became more vulnerable.Our study highlights the importance of thermal biological traits in evaluating the vulnerability of ectotherms in temperate plateau regions.展开更多
Poyang Lake,China's largest freshwater lake,is a critical wintering ground for most of the global Siberian Grane(Grus leucogeranus)population.However,increasingly prolonged dry seasons have degraded the natural we...Poyang Lake,China's largest freshwater lake,is a critical wintering ground for most of the global Siberian Grane(Grus leucogeranus)population.However,increasingly prolonged dry seasons have degraded the natural wetlands of Poyang Lake,forcing Siberian Cranes to shift to artificial habitats.From 2015 to 2023,field surveys revealed a substantial increase in the number of Siberian Cranes in artificial habitats,with peak counts reaching 3000individuals,accounting for up to 53%of the species'global population.Satellite telemetry of 13 individuals further confirmed the spatial use of these habitats,highlighting their consistent reliance on artificial sites over multiple years.Seven high-use hotspots were identified outside of Poyang Lake,including two artificial provisioning sites that supported dense foraging flocks for extended periods.Satellite telemetry confirmed this trend,with artificial habitats making up to 64.2%of the occurrence sites in some years.This reliance on artificial habitats was closely linked to the reduced tuber biomass in natural wetlands and low winter water levels in Poyang Lake,which collectively explained 83%of the variance in crane abundance in artificial habitats.Artificial habitat use peaked in December and January,indicating marked seasonal variation.Siberian Cranes also exhibited a pronounced circadian rhythm,foraging in artificial habitats during the day and returning to natural wetlands to roost at night.Despite the shift toward artificial habitats,natural wetlands remain critical for nighttime refuge.The continued dependence on artificial habitats raises concerns about disease transmission owing to dense congregations.Conservation strategies should prioritize both the careful management of artificial provisioning sites and the restoration of natural wetlands to improve food and habitat availability within natural ecosystems,ultimately enabling the return of Siberian Cranes to their traditional natural habitats.展开更多
As climate change intensifies,forests increasingly face the challenges posed by more frequent and severe droughts.However,the impacts of drought intensity on post-drought growth recovery and compensatory growth in tre...As climate change intensifies,forests increasingly face the challenges posed by more frequent and severe droughts.However,the impacts of drought intensity on post-drought growth recovery and compensatory growth in trees remain poorly understood.Understanding the mechanisms through which drought influences tree radial growth and accurately assessing how growth responds to different drought intensities is essential for forecasting forest dynamics.In this study,we used correlation analysis to identify the climatic limiting factors for the radial growth of P.schrenkiana Fisch.&C.A.Mey.(P.schrenkiana)across three elevations in the Western Tianshan Mountains of China.We assessed the impact of drought intensity on radial growth.By analyzing the growth resistance,recovery,and resilience of P.schrenkiana in relation to drought intensity,we quantified post-drought growth trajectories.Our key findings are as follows:1)Drought stress is the primary factor limiting the radial growth of P.schrenkiana.2)Tree growth responses vary significantly with elevation and drought intensity.As drought intensity increased,both resistance and recovery decreased.3)Compensatory growth occurred following moderate and severe droughts at all elevations.However,this was not observed in the first year after extreme droughts.These findings highlight the importance of the first post-drought year in determining the recovery trajectory of P.schrenkiana radial growth.展开更多
The influence of global climate change on endangered species is of growing concern, especially for rosewood species that are in urgent need of protection and restoration. Ecological niche models are commonly used to e...The influence of global climate change on endangered species is of growing concern, especially for rosewood species that are in urgent need of protection and restoration. Ecological niche models are commonly used to evaluate probable species’ distribution under climate change and contribute to decision-making to define efficient management strategies. A model was developed to forecast which habitat was most likely appropriate for the Dalbergia odorifera. We screened the main climatic variables that describe the current geographic distribution of the species based on maximum entropy modelling (Maxent). We subsequently assessed its potential future distribution under moderate (RCP2.6) and severe (RCP8.5) climate change scenarios for the years 2050 and 2070. The precipitation ranges of the wettest month and the warmest quarter are the primary limiting factors for the current distribution of D. odorifera among the climatic predictors. Climate change will be expected to have beneficial effects on the distribution range of D. odorifera. In conclusion, the main limits for the distribution of D. odorifera are determined by the level of precipitation and human activities. The results of this study indicate that the coasts of southern China and Chongqing will play a key role in the protection and restoration of D. odorifera in the future.展开更多
Rhododendron micranthum Turcz.is a shrub esteemed for its ornamental and medicinal attributes within the Changbai Mountain range of China.We selected 3-year saplings and subjected them to four distinct light condi-tio...Rhododendron micranthum Turcz.is a shrub esteemed for its ornamental and medicinal attributes within the Changbai Mountain range of China.We selected 3-year saplings and subjected them to four distinct light condi-tions:full light(CK),70%light(L1),50%light(L2),and 30%light(L3)to investigate variations in morphology,photosynthetic responses,stomatal ultrastructure as well as the mechanisms through which these saplings adapt to differing lighting environments.The results indicate that L2 leaves exhibit significantly greater length,width,and petiole development compared to other treatments across varying intensities.Over time,chlorophyll content and PSII levels in L2-treated saplings surpass those observed in other treatments;Proline(PRO),malondialdehyde(MDA),and soluble protein(SP)contents are markedly lower under L2 treatment.Catalase(CAT)and superoxide dismutase(SOD)demonstrate significant correlations across various light con-ditions but respond differently among treatments,indicat-ing distinct species sensitivities to light intensity while both contribute to environmental stress resistance mechanisms.Findings reveal that R.micranthum saplings at 50%light intensity benefit from enhanced protection via antioxidant enzymes,and shading reduces osmotic adjustment sub-stances yet increases chlorophyll content.Stomatal length/width along with conductance rates and net photosynthesis rates for L2 exceed those of CK,suggesting an improved photosynthetic structure conducive to efficient photosynthe-sis under this condition.Thus,moderate shading represents optimal growth at 50%illumination,a critical factor promot-ing sapling development.This research elucidates the ideal environment for R.micranthum adaptation to varying light conditions supporting future conservation initiatives.展开更多
Forest ecosystems are critical to ecological stability,yet their functionality is increasingly threatened by the growing frequency of drought,particularly in arid and semi-arid regions.While afforestation enhances for...Forest ecosystems are critical to ecological stability,yet their functionality is increasingly threatened by the growing frequency of drought,particularly in arid and semi-arid regions.While afforestation enhances forest cover in these areas,the capacity of planted forests to adapt to climate change is poorly understood.This study examines the drought resistance and adaptive capacity of planted and naturally growing Schrenk spruce(Picea schrenkiana Fisch.&C.A.Mey.)in the Ili River Basin,Xinjiang,China using tree-ring analysis.The results indicate that natural stands have a stronger correlation with meteorological factors than plantations.Over the past 50 years,significant growth declines occurred during 1995-1997,2007-2009,and 2012-2014,with natural forests showing a greater frequency and severity of declines compared to plantations.Planted stands demonstrated greater resistance to drought,whereas natural forests had higher resilience and recovery.Over time,natural forests have shown declining resistance to drought but increased resilience and recovery.Conversely,plantations showed declines in resistance and recovery but an increased capacity for recovery.Older natural forests are more prone to growth decline,while structurally simpler planted forests show stronger drought resistance.However,following periods of drought,natural forests demonstrated a stronger capacity for recovery.These findings provide valuable insights into the response of P.schrenkiana to climate change and offer support for the sustainable management and conservation of forest ecosystems in the Xinjiang region of China.展开更多
Acidobacteria is one of the most dominant and abundant phyla in soil,and was believed to have a wide range of metabolic and genetic functions. Relatively little is known about its community structure and elevational d...Acidobacteria is one of the most dominant and abundant phyla in soil,and was believed to have a wide range of metabolic and genetic functions. Relatively little is known about its community structure and elevational diversity patterns. We selected four elevation gradients from 1000 to 2800 m with typical vegetation types of the northern slope of Shennongjia Mountain in central China. The vegetation types were evergreen broadleaved forest,deciduous broadleaved forest,coniferous forest and sub-alpine shrubs. We analyzed the soil acidobacterial community composition,elevational patterns and the relationship between Acidobacteria subdivisions and soil enzyme activities by using the 16 S rRNA meta-sequencing technique and multivariate statistical analysis. The result found that 19 known subdivisions as well as an unclassified phylotype were presented in these forest sites,and Subdivision 6 has the highest number of detectable operational taxonomic units（OTUs）. A significant single peak distribution pattern（P 〈 0.05） between the OTU number and the elevation was observed. The Jaccard and Bray–Curtis index analysis showed that the soil Acidobacteria compositional similarity significantly decreased（P 〈 0.01） with the increase in elevation distance. Mantel test analysis showed the most of the soil Acidobacteria subdivisions had the significant relationship（P 〈 0.01） with different soil enzymes. Therefore,soil Acidobacteria may be involved in different ecosystem functions in global elemental cycles. Partial Mantel tests and CCA analysis showed that soil pH,soil temperature and plant diversity may be the key factors in shaping the soil Acidobacterial community structure.展开更多
Codon usage in chloroplast genome of six seed plants （Arabidopsis thaliana, Populus alba, Zea mays, Triticum aestivum, Pinus koraiensis and Cycas taitungensis） was analyzed to find general patterns of codon usage in...Codon usage in chloroplast genome of six seed plants （Arabidopsis thaliana, Populus alba, Zea mays, Triticum aestivum, Pinus koraiensis and Cycas taitungensis） was analyzed to find general patterns of codon usage in chloroplast genomes of seed plants. The results show that chloroplast genomes of the six seed plants had similar codon usage patterns, with a strong bias towards a high representation of NNA and NNT codons. In chloroplast genomes of the six seed plants, the effective number of codons （ENC） for most genes was similar to that of the expected ENC based on the GC content at the third codon position, but several genes with low ENC values were laying below the expected curve. All of these data indicate that codon usage was dominated by a mutational bias in chloroplast genomes of seed plants and that selection appeared to be limited to a subset of genes and to only subtly affect codon usage. Meantime, four, six, eight, nine, ten and 12 codons were defined as the optimal codons in chloroplast genomes of the six seed plants.展开更多
Freezing and thawing indices are not only of great significance for permafrost research but also are important indicators of the effects of climate change.However,to date,research on ground-surface freezing and thawin...Freezing and thawing indices are not only of great significance for permafrost research but also are important indicators of the effects of climate change.However,to date,research on ground-surface freezing and thawing indices and their relationship with air indices is limited.Based on daily air and ground-surface temperatures collected from 11 meteorological stations in the source region of the Yellow River,the freezing and thawing indices were calculated,and their spatial distribution and trends were analyzed.The air-freezing index(AFI),air-thawing index(ATI),ground surface-freezing index(GFI),ground surface-thawing index(GTI),air thawing-freezing index ratio(Na)and surface ground thawing-freezing index ratio(Ng)were 1554.64,1153.93,1.55,2484.85,850.57℃-days and 3.44,respectively.Altitude affected the spatial distribution of the freezing and thawing indices.As the altitude increased,the freezing indices gradually increased,and the thawing indices and thawing-freezing index ratio decreased.From 1980 to 2014,the AFI and GFI decreased at rates of 8.61 and 11.06℃-days a^(-1),the ATI and GTI increased at 9.65 and 14.53℃-days a^(-1),and Na and Ng significantly increased at 0.21 and 0.79 decade^(-1).Changes in the freezing and thawing indices were associated with increases in the air and ground-surface temperatures.The rates of change of the ground surface freezing and thawing indices were faster than the air ones because the rate of increase of the groundsurface temperature was faster than that of the air and the difference between the ground surface and air increased.The change point of the time series of freezing and thawing indices occurred in 2000–2001.After 2000–2001,the AFI and GFI were lower than before the change point,and the changing trend was lower.The ATI,GTI,Na and Ng during 2001–2014 were higher,with faster rates than before.In addition,the annual thawing indices composed a greater proportion of the mean annual air temperature and mean annual ground surface temperature than the annual freezing indices.This study provides the necessary basis for research on and prediction of permafrost changes,especially changes in the depth of the active permafrost layer,climate change,and possible evolution of the ecological environment over the source region of the Yellow River on the Qinghai-Tibet Plateau.展开更多
Honghu Lake,located in the southeast of Hubei Province,China,has suffered a severe disturbance during the past few decades.To restore the ecosystem,the Honghu Lake Wetland Protection and Restoration Demonstration Proj...Honghu Lake,located in the southeast of Hubei Province,China,has suffered a severe disturbance during the past few decades.To restore the ecosystem,the Honghu Lake Wetland Protection and Restoration Demonstration Project(HLWPRDP) has been implemented since 2004.A back propagation(BP) artificial neural network(ANN) approach was applied to evaluatinig the ecosystem health of the Honghu Lake wetland.And the effectiveness of the HLWPRDP was also assessed by comparing the ecosystem health before and after the project.Particularly,12 ecosystem health indices were used as evaluation parameters to establish a set of three-layer BP ANNs.The output is one layer of ecosystem health index.After training and testing the BP ANNs,an optimal model of BP ANNs was selected to assess the ecosystem health of the Honghu Lake wetland.The result indicates that four stages can be identified based on the change of the ecosystem health from 1990 to 2008 and the ecosystem health index ranges from morbidity before the implementation of HLWPRDP(in 2002) to middle health after the implementation of the HLWPRDP(in 2005).It demonstrates that the HLWPRDP is effective and the BP ANN could be used as a tool for the assessment of ecosystem health.展开更多
‘Zhongqiusucui’ jujube secondary shoots were treated with 3-indolebutyric acid(IBA) at three concentrations, 500, 1000 and 1500 mg/L. Results show that IBA could significantly enhance rooting and root characteristic...‘Zhongqiusucui’ jujube secondary shoots were treated with 3-indolebutyric acid(IBA) at three concentrations, 500, 1000 and 1500 mg/L. Results show that IBA could significantly enhance rooting and root characteristics of cuttings and were best with IBA at 1500 mg/L. In the rooting process, the formation of adventitious roots was related to the consumption and accumulation of nutrients(soluble sugars and proteins) and the changes in endogenous hormones in phloem, leaf tips and leaf bases. The rooting of cuttings had a positive correlation with the consumption of soluble sugars during the period of callus formation and with the accumulation of soluble sugars during adventitious root formation and growth. Rooting was positively related to the breakdown of soluble proteins in the phloem when the callus formed, and had a positive correlation with its accumulation during adventitious root formation and growth. Leaf tips and leaf bases showed a reverse trend in changes of soluble protein. However, together with the phloem, leaf tips and leaf bases regulated and controlled the formation and development of adventitious roots. The main activities of soluble proteins exist in the leaf tips as this was the main source of soluble proteins. The relation between rooting and IAA(indole-3-acetic acid) content in phloem was positive and thus a high concentration of IAA could benefit the induction and formation of adventitious roots. However, rooting was negatively related with ABA(abscisic acid) and GA(gibberellic acid) and a high concentration of both could inhibit the induction and formation of adventitious roots. Rooting had a positive correlation with phloem IAA/ABA ratios, and higher ratios could improve rooting. Low concentrations of ZR(zeatin riboside) triggered the induction of adventitious roots, while higher concentrations promoted root growth.Endogenous hormones in leaf tips and bases had an impact on rooting. The activities of endogenous hormones mainly existed in leaf tips because they play a major role in the production and consumption of IAA and its ABA content increased during rooting. The ZR in leaf tips influenced the rooting of cuttings, especially in the callus formation and rooting stage. Leaf tips were the main source of GA.展开更多
A study was conducted to explore the mechanism that emissions of volatile organic compounds(VOC)from heated needles and twigs(200°C,within 15 min)of Pinus pumila affect fire behaviours using the technology of The...A study was conducted to explore the mechanism that emissions of volatile organic compounds(VOC)from heated needles and twigs(200°C,within 15 min)of Pinus pumila affect fire behaviours using the technology of Thermal Desorption-Gas Chromatography-Mass Spectrometry(TD-GC-MS).The results indicated that the main components of VOC from heated needles and twigs are terpenoids.Most of these terpenoids are monoterpenes.Terpenoids account for 72.93%for the needles and 92.40%for the twigs of the total VOC,and their emission ratios are 61.200μg·g-1 and 217.060μg·g-1 respectively.Heated twigs can emit more terpenoids than heated needles because twigs had more volatile oils than needles.In actual fires,these large amounts of terpenoid emissions,especially the monoterpene emissions,have strong effects on fire behaviors that are not only in the initial stage but also in the fast propagation stage of fires.These flammable gases are capable of causing violent combustion and creating crown fires.In addition,if these gases accumulate in an uneven geographical area,there will be a possible for eruptive fires and/or fires flashover to occur.展开更多
Climate warming has a rapid and far-reaching impact on forest fire management in the boreal forests of China. Regional climate model outputs and the Canadian Forest Fire Weather Index （FWI） Sys- tem were used to ana...Climate warming has a rapid and far-reaching impact on forest fire management in the boreal forests of China. Regional climate model outputs and the Canadian Forest Fire Weather Index （FWI） Sys- tem were used to analyze changes to fire danger and the fire season for future periods under IPCC Special Report on Emission Scenarios （SRES） A2 and B2, and the data will guide future fire management planning. We used regional climate in China （1961 1990） as our validation data, and the period （1991–2100） was modeled under SRES A2 and B2 through the weather simulated by the regional climate model system （PRECIS）. Meteorological data and fire danger were interpolated to 1 km 2 by using ANUSPLIN software. The average FWI value for future spring fire sea- sons under Scenarios A2 and B2 shows an increase over most of the region. Compared with the baseline, FWI averages of spring fire season will increase by 0.40, 0.26 and 1.32 under Scenario A2, and increase by 0.60, 1.54 and 2.56 under Scenario B2 in 2020s, 2050s and 2080s, respectively. FWI averages of autumn fire season also show an increase over most of the region. FWI values increase more for Scenario B2 than for Scenario A2 in the same periods, particularly during the 2050s and 2080s. Average future FWI values will increase under both scenarios for autumn fire season. The potential burned areas are expected to increase by 10% and 18% in spring for 2080s under Scenario A2 and B2, respectively. Fire season will be prolonged by 21 and 26 days under ScenariosA2 and B2 in 2080s respectively.展开更多
基金supported by the National Natural Science Foundation of China(32471964)。
文摘The collection and annotation of lar ge-scale bird datasets are resource-intensive and time-consuming processes that significantly limit the scalability and accuracy of biodiversity monitoring systems.While self-supervised learning(SSL)has emerged as a promising approach for leveraging unannotated data,current SSL methods face two critical challenges in bird species recognition:(1)long-tailed data distributions that result in poor performance on underrepresented species;and(2)domain shift issues caused by data augmentation strategies designed to mitigate class imbalance.Here we present SDNet,a novel SSL-based bird recognition framework that integrates diffusion models with large language models(LLMs)to overcome these limitations.SDNet employs LLMs to generate semantically rich textual descriptions for tail-class species by prompting the models with species taxonomy,morphological attributes,and habitat information,producing detailed natural language priors that capture fine-grained visual characteristics(e.g.,plumage patterns,body proportions,and distinctive markings).These textual descriptions are subsequently used by a conditional diffusion model to synthesize new bird image samples through cross-attention mechanisms that fuse textual embeddings with intermediate visual feature representations during the denoising process,ensuring generated images preserve species-specific morphological details while maintaining photorealistic quality.Additionally,we incorporate a Swin Transformer as the feature extraction backbone whose hierarchical window-based attention mechanism and shifted windowing scheme enable multi-scale local feature extraction that proves particularly effective at capturing finegrained discriminative patterns(such as beak shape and feather texture)while mitigating domain shift between synthetic and original images through consistent feature representations across both data sources.SDNet is validated on both a self-constructed dataset(Bird_BXS)an d a publicly available benchmark(Birds_25),demonstrating substantial improvements over conventional SSL approaches.Our results indicate that the synergistic integration of LLMs,diffusion models,and the Swin Transformer architecture contributes significantly to recognition accuracy,particularly for rare and morphologically similar species.These findings highlight the potential of SDNet for addressing fundamental limitations of existing SSL methods in avian recognition tasks and establishing a new paradigm for efficient self-supervised learning in large-scale ornithological vision applications.
基金funded by the Chinese Academy of Forestry-Special funds for basic scientific research service expenses of the central level public welfare research institutes(Grant No.CAFYBB2020QD001)the National Natural Science Foundation of China(Grant Nos.32101550,32271917)+1 种基金Jiangsu Agricultural Science and Technology Innovation Fund(Grant No.CX(24)3052)National Forestry and Grassland Administration’s Center for Science and Technology Development Projects(Grant No.KJZXSA202202).
文摘Catalpa bungei,a fast-growing timber tree,is threatened by the lepidopteran pest Omphisa plagialis.Previous studies in our laboratory successfully generated transgenic C.bungei lines overexpressing Cry genes(Cry1Ab,Cry2A,and Cry9-2)that exhibited resistance to O.plagialis,but their potential impact on soil bacterial communities remains unclear.In this study,we analyzed nine transgenic C.bungei lines(three independent lines for each Cry gene)to characterize their rhizosphere bacterial communities using high-throughput sequencing of the 16S ribosomal DNA(rDNA)V4-V5 regions.A total of 628 amplicon sequence variants(ASVs)were shared among all transgenic and wild-type(WT)lines,forming a stable core microbiome dominated by Proteobacteria,Bacteroidota,Acidobacteriota,and Actinobacteriota.Alpha diversity showed no significant differences,while beta diversity revealed minor but distinct compositional shifts.Cry1Ab lines exhibited higher abundances of fast-growing taxa,particularly Proteobacteria and Bacteroidota;Cry2A lines displayed intermediate profiles,whereas Cry9-2 lines were nearly indistinguishable from WT communities.Linear discriminant analysis of the effect size revealed significant enrichment of taxa such as Burkholderiaceae and Ralstonia in the Cry1Ab rhizosphere,in contrast to the higher abundance of Chloroflexi in the WT.Functional predictions indicated consistent metabolic pathways across all treatments,suggesting strong ecological redundancy.This study demonstrates minimal impact on rhizosphere microbial communities in transgenic C.bungei plants.The Cry9-2 construct exhibited superior environmental stability,whereas the Cry1Ab construct caused only slight but ecologically acceptable shifts.These findings support the ecological safety of Bt-transgenic C.bungei and identify Cry9-2 as a particularly favorable candidate for forestry applications.This comparative evaluation of three Cry genes in a tree species provides a framework for future gene-specific biosafety assessments in woody plants.
基金supported by grants from the National Natural Science Foundation of China(31861143023 and 31872252)the Fundamental Research Funds for the Central Universities(2572019AA09)the Strategic Priority Research Program of the Chinese Academy of Sciences(XDA20050201).
文摘The survival of ectotherms worldwide is threatened by climate change.Whether increasing temperatures increase the vulnerability of ectotherms inhabiting temperate plateau areas remains unclear.To understand altitudinal variation in the vulnerability of plateau ectotherms to climate warming,Qinghai toad-headed lizards(Phrynocephalus vlangalii)were subjected to semi-natural enclosure experiments with simulated warming at high(2,600 m)and superhigh(3,600 m)elevations of the Dangjin Mountain,China.Our results revealed that the thermoregulatory effectiveness and warming tolerance(WT)of the toad-headed lizards were significantly affected by climate warming at both elevations,but their thermal sensitivity remained unchanged.After warming,the thermoregulatory effectiveness of lizards at superhigh elevations decreased because of the improved environmental thermal quality,whereas that of lizards at high-elevation conditions increased.Although the body temperature selected by high-elevation lizards was also significantly increased,the proportion of their active body temperature falling within the set-point temperature range decreased.This indicates that it is difficult for high-elevation lizards to adjust their body temperatures within a comfortable range under climate warming.Variations in the WT and thermal safety margin(TSM)under climate warming revealed that lizards at the superhigh elevation benefited from improved environmental thermal quality,whereas those at the high elevation originally on the edge of the TSM faced more severe threats and became more vulnerable.Our study highlights the importance of thermal biological traits in evaluating the vulnerability of ectotherms in temperate plateau regions.
基金supported by the National Natural Science Foundation of China(No.32260275)Fundamental Research Funds of CAF(CAFYBB2024ZA033)。
文摘Poyang Lake,China's largest freshwater lake,is a critical wintering ground for most of the global Siberian Grane(Grus leucogeranus)population.However,increasingly prolonged dry seasons have degraded the natural wetlands of Poyang Lake,forcing Siberian Cranes to shift to artificial habitats.From 2015 to 2023,field surveys revealed a substantial increase in the number of Siberian Cranes in artificial habitats,with peak counts reaching 3000individuals,accounting for up to 53%of the species'global population.Satellite telemetry of 13 individuals further confirmed the spatial use of these habitats,highlighting their consistent reliance on artificial sites over multiple years.Seven high-use hotspots were identified outside of Poyang Lake,including two artificial provisioning sites that supported dense foraging flocks for extended periods.Satellite telemetry confirmed this trend,with artificial habitats making up to 64.2%of the occurrence sites in some years.This reliance on artificial habitats was closely linked to the reduced tuber biomass in natural wetlands and low winter water levels in Poyang Lake,which collectively explained 83%of the variance in crane abundance in artificial habitats.Artificial habitat use peaked in December and January,indicating marked seasonal variation.Siberian Cranes also exhibited a pronounced circadian rhythm,foraging in artificial habitats during the day and returning to natural wetlands to roost at night.Despite the shift toward artificial habitats,natural wetlands remain critical for nighttime refuge.The continued dependence on artificial habitats raises concerns about disease transmission owing to dense congregations.Conservation strategies should prioritize both the careful management of artificial provisioning sites and the restoration of natural wetlands to improve food and habitat availability within natural ecosystems,ultimately enabling the return of Siberian Cranes to their traditional natural habitats.
基金supported by Tianshan Talent Program of Xinjiang(Nos.2022TSYCCX0003 and 2024TSYCCX0041)the National Natural Science Foundation of China(Nos.42375054 and 42375196)+2 种基金the Desert Meteorological Science Research Foundation of China(Nos.Sqj2021018 and Sqj20240018)the Young Meteorological Talent Program of China Meteorological Administration and Youth Innovation Team of China Meteorological Administration(No.CMA2023QN08)the Strategic Priority Research Program of Chinese Academy of Sciences(No.XDA20100306).
文摘As climate change intensifies,forests increasingly face the challenges posed by more frequent and severe droughts.However,the impacts of drought intensity on post-drought growth recovery and compensatory growth in trees remain poorly understood.Understanding the mechanisms through which drought influences tree radial growth and accurately assessing how growth responds to different drought intensities is essential for forecasting forest dynamics.In this study,we used correlation analysis to identify the climatic limiting factors for the radial growth of P.schrenkiana Fisch.&C.A.Mey.(P.schrenkiana)across three elevations in the Western Tianshan Mountains of China.We assessed the impact of drought intensity on radial growth.By analyzing the growth resistance,recovery,and resilience of P.schrenkiana in relation to drought intensity,we quantified post-drought growth trajectories.Our key findings are as follows:1)Drought stress is the primary factor limiting the radial growth of P.schrenkiana.2)Tree growth responses vary significantly with elevation and drought intensity.As drought intensity increased,both resistance and recovery decreased.3)Compensatory growth occurred following moderate and severe droughts at all elevations.However,this was not observed in the first year after extreme droughts.These findings highlight the importance of the first post-drought year in determining the recovery trajectory of P.schrenkiana radial growth.
基金the National Natural Science Foundation of China(NSFC 31761143002,NSFC 3207178)China Postdoctoral Science Foundation(2022M710405)the National Forest and Grassland Genetic Recourse(No.2005DKA21003).
文摘The influence of global climate change on endangered species is of growing concern, especially for rosewood species that are in urgent need of protection and restoration. Ecological niche models are commonly used to evaluate probable species’ distribution under climate change and contribute to decision-making to define efficient management strategies. A model was developed to forecast which habitat was most likely appropriate for the Dalbergia odorifera. We screened the main climatic variables that describe the current geographic distribution of the species based on maximum entropy modelling (Maxent). We subsequently assessed its potential future distribution under moderate (RCP2.6) and severe (RCP8.5) climate change scenarios for the years 2050 and 2070. The precipitation ranges of the wettest month and the warmest quarter are the primary limiting factors for the current distribution of D. odorifera among the climatic predictors. Climate change will be expected to have beneficial effects on the distribution range of D. odorifera. In conclusion, the main limits for the distribution of D. odorifera are determined by the level of precipitation and human activities. The results of this study indicate that the coasts of southern China and Chongqing will play a key role in the protection and restoration of D. odorifera in the future.
基金funded by the National Natural Science Foundation of China(No.32171770)Natural Science Foundation Program of Jilin Provincial Department of Education(No.JJKH20230074KJ).
文摘Rhododendron micranthum Turcz.is a shrub esteemed for its ornamental and medicinal attributes within the Changbai Mountain range of China.We selected 3-year saplings and subjected them to four distinct light condi-tions:full light(CK),70%light(L1),50%light(L2),and 30%light(L3)to investigate variations in morphology,photosynthetic responses,stomatal ultrastructure as well as the mechanisms through which these saplings adapt to differing lighting environments.The results indicate that L2 leaves exhibit significantly greater length,width,and petiole development compared to other treatments across varying intensities.Over time,chlorophyll content and PSII levels in L2-treated saplings surpass those observed in other treatments;Proline(PRO),malondialdehyde(MDA),and soluble protein(SP)contents are markedly lower under L2 treatment.Catalase(CAT)and superoxide dismutase(SOD)demonstrate significant correlations across various light con-ditions but respond differently among treatments,indicat-ing distinct species sensitivities to light intensity while both contribute to environmental stress resistance mechanisms.Findings reveal that R.micranthum saplings at 50%light intensity benefit from enhanced protection via antioxidant enzymes,and shading reduces osmotic adjustment sub-stances yet increases chlorophyll content.Stomatal length/width along with conductance rates and net photosynthesis rates for L2 exceed those of CK,suggesting an improved photosynthetic structure conducive to efficient photosynthe-sis under this condition.Thus,moderate shading represents optimal growth at 50%illumination,a critical factor promot-ing sapling development.This research elucidates the ideal environment for R.micranthum adaptation to varying light conditions supporting future conservation initiatives.
基金supported by the Tianshan Talent Program of Xinjiang(2022TSYCCX0003,2024TSYCCX0041)the National Natural Science Foundation of China(42375054)+1 种基金the Desert Meteorological Science Research Foundation of China(Sqj2021018)the Young Meteorological Talent Program of China Meteorological Administration and Youth Innovation Team of China Meteorological Administration(CMA2023QN08)。
文摘Forest ecosystems are critical to ecological stability,yet their functionality is increasingly threatened by the growing frequency of drought,particularly in arid and semi-arid regions.While afforestation enhances forest cover in these areas,the capacity of planted forests to adapt to climate change is poorly understood.This study examines the drought resistance and adaptive capacity of planted and naturally growing Schrenk spruce(Picea schrenkiana Fisch.&C.A.Mey.)in the Ili River Basin,Xinjiang,China using tree-ring analysis.The results indicate that natural stands have a stronger correlation with meteorological factors than plantations.Over the past 50 years,significant growth declines occurred during 1995-1997,2007-2009,and 2012-2014,with natural forests showing a greater frequency and severity of declines compared to plantations.Planted stands demonstrated greater resistance to drought,whereas natural forests had higher resilience and recovery.Over time,natural forests have shown declining resistance to drought but increased resilience and recovery.Conversely,plantations showed declines in resistance and recovery but an increased capacity for recovery.Older natural forests are more prone to growth decline,while structurally simpler planted forests show stronger drought resistance.However,following periods of drought,natural forests demonstrated a stronger capacity for recovery.These findings provide valuable insights into the response of P.schrenkiana to climate change and offer support for the sustainable management and conservation of forest ecosystems in the Xinjiang region of China.
基金supported by the Public Welfare Project of the National Scientific Research Institution (No.CAFRIFEEP201101),Chinathe National Biological Specimens and Resources Sharing Platform in Nature Reserve (No.2005DKA21404)
文摘Acidobacteria is one of the most dominant and abundant phyla in soil,and was believed to have a wide range of metabolic and genetic functions. Relatively little is known about its community structure and elevational diversity patterns. We selected four elevation gradients from 1000 to 2800 m with typical vegetation types of the northern slope of Shennongjia Mountain in central China. The vegetation types were evergreen broadleaved forest,deciduous broadleaved forest,coniferous forest and sub-alpine shrubs. We analyzed the soil acidobacterial community composition,elevational patterns and the relationship between Acidobacteria subdivisions and soil enzyme activities by using the 16 S rRNA meta-sequencing technique and multivariate statistical analysis. The result found that 19 known subdivisions as well as an unclassified phylotype were presented in these forest sites,and Subdivision 6 has the highest number of detectable operational taxonomic units（OTUs）. A significant single peak distribution pattern（P 〈 0.05） between the OTU number and the elevation was observed. The Jaccard and Bray–Curtis index analysis showed that the soil Acidobacteria compositional similarity significantly decreased（P 〈 0.01） with the increase in elevation distance. Mantel test analysis showed the most of the soil Acidobacteria subdivisions had the significant relationship（P 〈 0.01） with different soil enzymes. Therefore,soil Acidobacteria may be involved in different ecosystem functions in global elemental cycles. Partial Mantel tests and CCA analysis showed that soil pH,soil temperature and plant diversity may be the key factors in shaping the soil Acidobacterial community structure.
基金supported in part by the Hi-Tech Re-search and Development Program of China ("863" Program) (No. 2007AA02Z329)the National Natural Science Foundation of China (Grant No. 20060213024)
文摘Codon usage in chloroplast genome of six seed plants （Arabidopsis thaliana, Populus alba, Zea mays, Triticum aestivum, Pinus koraiensis and Cycas taitungensis） was analyzed to find general patterns of codon usage in chloroplast genomes of seed plants. The results show that chloroplast genomes of the six seed plants had similar codon usage patterns, with a strong bias towards a high representation of NNA and NNT codons. In chloroplast genomes of the six seed plants, the effective number of codons （ENC） for most genes was similar to that of the expected ENC based on the GC content at the third codon position, but several genes with low ENC values were laying below the expected curve. All of these data indicate that codon usage was dominated by a mutational bias in chloroplast genomes of seed plants and that selection appeared to be limited to a subset of genes and to only subtly affect codon usage. Meantime, four, six, eight, nine, ten and 12 codons were defined as the optimal codons in chloroplast genomes of the six seed plants.
基金funded by the National Science and Technology Support Plan(2015BAD07B02)
文摘Freezing and thawing indices are not only of great significance for permafrost research but also are important indicators of the effects of climate change.However,to date,research on ground-surface freezing and thawing indices and their relationship with air indices is limited.Based on daily air and ground-surface temperatures collected from 11 meteorological stations in the source region of the Yellow River,the freezing and thawing indices were calculated,and their spatial distribution and trends were analyzed.The air-freezing index(AFI),air-thawing index(ATI),ground surface-freezing index(GFI),ground surface-thawing index(GTI),air thawing-freezing index ratio(Na)and surface ground thawing-freezing index ratio(Ng)were 1554.64,1153.93,1.55,2484.85,850.57℃-days and 3.44,respectively.Altitude affected the spatial distribution of the freezing and thawing indices.As the altitude increased,the freezing indices gradually increased,and the thawing indices and thawing-freezing index ratio decreased.From 1980 to 2014,the AFI and GFI decreased at rates of 8.61 and 11.06℃-days a^(-1),the ATI and GTI increased at 9.65 and 14.53℃-days a^(-1),and Na and Ng significantly increased at 0.21 and 0.79 decade^(-1).Changes in the freezing and thawing indices were associated with increases in the air and ground-surface temperatures.The rates of change of the ground surface freezing and thawing indices were faster than the air ones because the rate of increase of the groundsurface temperature was faster than that of the air and the difference between the ground surface and air increased.The change point of the time series of freezing and thawing indices occurred in 2000–2001.After 2000–2001,the AFI and GFI were lower than before the change point,and the changing trend was lower.The ATI,GTI,Na and Ng during 2001–2014 were higher,with faster rates than before.In addition,the annual thawing indices composed a greater proportion of the mean annual air temperature and mean annual ground surface temperature than the annual freezing indices.This study provides the necessary basis for research on and prediction of permafrost changes,especially changes in the depth of the active permafrost layer,climate change,and possible evolution of the ecological environment over the source region of the Yellow River on the Qinghai-Tibet Plateau.
基金Under the auspices of National Natural Science Foundation of China (No 40871251)Knowledge Innovation Programs of Chinese Academy of Sciences (No KZCX2-YW-141)
文摘Honghu Lake,located in the southeast of Hubei Province,China,has suffered a severe disturbance during the past few decades.To restore the ecosystem,the Honghu Lake Wetland Protection and Restoration Demonstration Project(HLWPRDP) has been implemented since 2004.A back propagation(BP) artificial neural network(ANN) approach was applied to evaluatinig the ecosystem health of the Honghu Lake wetland.And the effectiveness of the HLWPRDP was also assessed by comparing the ecosystem health before and after the project.Particularly,12 ecosystem health indices were used as evaluation parameters to establish a set of three-layer BP ANNs.The output is one layer of ecosystem health index.After training and testing the BP ANNs,an optimal model of BP ANNs was selected to assess the ecosystem health of the Honghu Lake wetland.The result indicates that four stages can be identified based on the change of the ecosystem health from 1990 to 2008 and the ecosystem health index ranges from morbidity before the implementation of HLWPRDP(in 2002) to middle health after the implementation of the HLWPRDP(in 2005).It demonstrates that the HLWPRDP is effective and the BP ANN could be used as a tool for the assessment of ecosystem health.
基金supported by the national 948 subject ‘Introduction of fresh-eating jujube cultivar and new cultivating technology from Israel(2012-4-61)’
文摘‘Zhongqiusucui’ jujube secondary shoots were treated with 3-indolebutyric acid(IBA) at three concentrations, 500, 1000 and 1500 mg/L. Results show that IBA could significantly enhance rooting and root characteristics of cuttings and were best with IBA at 1500 mg/L. In the rooting process, the formation of adventitious roots was related to the consumption and accumulation of nutrients(soluble sugars and proteins) and the changes in endogenous hormones in phloem, leaf tips and leaf bases. The rooting of cuttings had a positive correlation with the consumption of soluble sugars during the period of callus formation and with the accumulation of soluble sugars during adventitious root formation and growth. Rooting was positively related to the breakdown of soluble proteins in the phloem when the callus formed, and had a positive correlation with its accumulation during adventitious root formation and growth. Leaf tips and leaf bases showed a reverse trend in changes of soluble protein. However, together with the phloem, leaf tips and leaf bases regulated and controlled the formation and development of adventitious roots. The main activities of soluble proteins exist in the leaf tips as this was the main source of soluble proteins. The relation between rooting and IAA(indole-3-acetic acid) content in phloem was positive and thus a high concentration of IAA could benefit the induction and formation of adventitious roots. However, rooting was negatively related with ABA(abscisic acid) and GA(gibberellic acid) and a high concentration of both could inhibit the induction and formation of adventitious roots. Rooting had a positive correlation with phloem IAA/ABA ratios, and higher ratios could improve rooting. Low concentrations of ZR(zeatin riboside) triggered the induction of adventitious roots, while higher concentrations promoted root growth.Endogenous hormones in leaf tips and bases had an impact on rooting. The activities of endogenous hormones mainly existed in leaf tips because they play a major role in the production and consumption of IAA and its ABA content increased during rooting. The ZR in leaf tips influenced the rooting of cuttings, especially in the callus formation and rooting stage. Leaf tips were the main source of GA.
基金supported by National Natural Science Foundation of China(30872037,31070587)Open Project Program of State Key Laboratory of Fire Science,University of Science and Technology of China(HZ2008-KF08)
文摘A study was conducted to explore the mechanism that emissions of volatile organic compounds(VOC)from heated needles and twigs(200°C,within 15 min)of Pinus pumila affect fire behaviours using the technology of Thermal Desorption-Gas Chromatography-Mass Spectrometry(TD-GC-MS).The results indicated that the main components of VOC from heated needles and twigs are terpenoids.Most of these terpenoids are monoterpenes.Terpenoids account for 72.93%for the needles and 92.40%for the twigs of the total VOC,and their emission ratios are 61.200μg·g-1 and 217.060μg·g-1 respectively.Heated twigs can emit more terpenoids than heated needles because twigs had more volatile oils than needles.In actual fires,these large amounts of terpenoid emissions,especially the monoterpene emissions,have strong effects on fire behaviors that are not only in the initial stage but also in the fast propagation stage of fires.These flammable gases are capable of causing violent combustion and creating crown fires.In addition,if these gases accumulate in an uneven geographical area,there will be a possible for eruptive fires and/or fires flashover to occur.
基金support by National Science and Technology Support Plan(2007BAC03A02)National Natural Science Foundation of China(30671695)
文摘Climate warming has a rapid and far-reaching impact on forest fire management in the boreal forests of China. Regional climate model outputs and the Canadian Forest Fire Weather Index （FWI） Sys- tem were used to analyze changes to fire danger and the fire season for future periods under IPCC Special Report on Emission Scenarios （SRES） A2 and B2, and the data will guide future fire management planning. We used regional climate in China （1961 1990） as our validation data, and the period （1991–2100） was modeled under SRES A2 and B2 through the weather simulated by the regional climate model system （PRECIS）. Meteorological data and fire danger were interpolated to 1 km 2 by using ANUSPLIN software. The average FWI value for future spring fire sea- sons under Scenarios A2 and B2 shows an increase over most of the region. Compared with the baseline, FWI averages of spring fire season will increase by 0.40, 0.26 and 1.32 under Scenario A2, and increase by 0.60, 1.54 and 2.56 under Scenario B2 in 2020s, 2050s and 2080s, respectively. FWI averages of autumn fire season also show an increase over most of the region. FWI values increase more for Scenario B2 than for Scenario A2 in the same periods, particularly during the 2050s and 2080s. Average future FWI values will increase under both scenarios for autumn fire season. The potential burned areas are expected to increase by 10% and 18% in spring for 2080s under Scenario A2 and B2, respectively. Fire season will be prolonged by 21 and 26 days under ScenariosA2 and B2 in 2080s respectively.
