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During its 6,300-km course from the Tibetan Plateau to the ocean, the Yangtze River is joined by two large lakes: Dongting Lake and Poyang Lake. We explain why these lakes exist. Deglaciation forced the ocean adjacent to the Yangtze mouth to rise ∼120 m. This forced a wave of rising water surface elevation and concomitant bed aggradation upstream. While aggradation attenuated upstream, the low bed slope of the Middle-Lower Yangtze River (∼2 × 10-5 near Wuhan) made it susceptible to sea level rise. The main stem, sourced at 5,054 m above sea level, had a substantial sediment load to “fight” against water surface level rise by means of bed aggradation. The tributaries of the Middle-Lower Yangtze have reliefs of approximately hundreds of meters, and did not have enough sediment supply to fill the tributary accommodation space created by main-stem aggradation. We show that the resulting tributary blockage likely gave rise to the lakes. We justify this using field data and numerical modeling, and derive a dimensionless number capturing the critical rate of water surface rise for blockage versus nonblockage. [ABSTRACT FROM AUTHOR]

Caragana is endemic to temperate Asia, with most species distributed on the Qinghai–Tibetan Plateau (QTP) and in Northwestern China. Consequently its biogeography should be hypothesized to have been affected by QTP uplift. To examine the biogeography of Caragana in relation to QTP uplift and consequent interior aridification, we conducted molecular dating analyses based on three genes (ITS, cpDNA trnS- trnG and rbcL). Results from relaxed Bayesian BEAST, relaxed Bayesian Multidivtime, and PL (penalized likelihood) indicate that QTP uplift, especially the onset of Himalayan motion at 21–17 Ma, triggered the origin of Caragana (with estimated ages 16–14 Ma). The subsequent QTP rapid uplift at 8 Ma is inferred to have driven the evolution and diversification of the three major clades of Caragana: section Caragana (northern China and the Junggar–Altai–Sayan region), section Frutescentes (Central Asia), and sections Bracteolatae and Jubatae, centered in the QTP. A rapid and active speciation process occurring in the QTP intense uplift at 3.4–1.8 Ma, is indicated by the chronogram. [ABSTRACT FROM AUTHOR]

The Songpan-Garze fold belt, located in the eastern part of the Tibetan Plateau, covers a huge triangular area bounded by the Yangtze (South China), the North China and the Tibetan Plateau blocks. In the northeastern part of the Songpan-Garze fold belt, the Yanggon and Maoergai granitoids provide insights into regional tectono-magmatic events, basement nature and tectonic evolution. U–Pb zircon SHRIMP dating shows that the Yanggon and Maoergai granitoids have magmatic crystallization ages of 221 ± 3.8 Ma and 216 ± 5.7 Ma, respectively. Both the granitoids display adakitic geochemical signatures, suggesting that their magma was derived from partial melting of thickened lower crust. Pb–Sr–Nd isotopic compositions for granitoids reveal that there is an unexposed Proterozoic basement in the Songpan-Garze belt, which has an affinity with the Yangtze block. During development of the Paleo-Tethys ocean, the basement of the Songpan-Garze belt would be a peninsula approaching the Paleo-Tethys ocean from the Yangtze block. [ABSTRACT FROM AUTHOR]

The genus Caragana Fabr., consisting of approximately 70 species, has a temperate Asian distribution and occurs mainly in the drought and cold regions of the northwestern and southwestern Tibetan Plateau of China. The distribution pattern of the genus was investigated using dispersal-vicariance analysis (DIVA). The results indicate that vicariance versus dispersal plays a major role in the evolution of the genus and that short-distance dispersal also exists. There is no fossil record of this genus. Therefore, Caragana is inferred as an advanced taxon in terms of its limited temperate Asian distribution. Based on the morphological variation and ecological adaptation in Caragana, the generic speciation is postulated to be related to the uplifting of the Tibetan Plateau and to the increasing arid conditions of Central Asian lands since the Neogene. The Mongolian Plateau and the Tibetan Plateau are hypothesized as the barriers of vicariance between East Asia and western Central Asia. (Managing editor: Ya-Qin) [ABSTRACT FROM AUTHOR]

The mechanisms driving crustal deformation and uplift of orogenic plateaus are fundamental to continental tectonics. Large‐scale crustal flow has been hypothesized to occur in eastern Tibet, but it remains controversial due to a lack of geologic evidence. Geochemical and isotopic data from Cenozoic igneous rocks in the eastern Tibet‐Gongga‐Zheduo intrusive massif, provide a way to test this model. Modeling results suggest that Cenozoic magmas originated at depths of ∼30–40 km, the depth that crustal flow has been postulated to occur at. Detailed isotopic analyses indicate that the igneous rocks are derived from partial melting of the local Songpan‐Ganzi crust, arguing against a long‐distance crustal flow. Episodic magmatism during the Cenozoic showing a repeated shifting of magmatic sources can be correlated with crustal uplift. The continued indentation of the Indian Block and upwelling of the asthenosphere contribute to the crustal deformation, magmatism, and uplift. Plain Language Summary: How the Tibetan Plateau grows outward and deformed remains controversial. A large‐scale crustal flow model has been favored for the expansion of the southeast Tibetan Plateau, arguing that crustal materials could flow hundreds of km resulting in crustal thickening and uplift. Detailed geochemical and isotopic investigations on the largest intrusion (Gongga‐Zheduo) in the eastern margin of the Tibetan Plateau show that their magmatic source is local crustal rocks of the Songpan‐Ganzi terrane without the input of crustal materials from central Tibet. Thermodynamic and trace element modeling results show that the Cenozoic magma is derived from ∼30 to 40 km depth, similar to the depth of postulated crustal flow. The results are inconsistent with the large‐scale eastward crustal flow model. A repeated shifting of magmatic sources during the Cenozoic is correlated with crustal uplift. Mantle‐crust interaction plays a primary role in the formation of magmatism and modifying crustal rheology. The continued collision between the Indian and Asian blocks and upwelling of the asthenosphere contribute to the crustal deformation and uplift. Key Points: Isotopic and thermodynamic modeling results indicate that Gongga‐Zheduo granitic rocks in eastern Tibet are sourced from the local crustNo crustal materials from central Tibet are observed in eastern Tibet arguing against the large‐scale crustal flow modelCenozoic episodic magmatism in eastern Tibet with a repeated vertical shifting of sources is correlated with staged crustal uplift [ABSTRACT FROM AUTHOR]

Over‐estimation of summer precipitation over the Tibetan Plateau (TP) is a well‐known and persistent problem in most climate models. This study demonstrates the impact of a Gaussian Probability Density Function cloud fraction scheme on rainfall simulations using the Weather Research and Forecasting model. It is found that this scheme in both 0.1° and 0.05° resolutions significantly reduces the wet bias through both local feedbacks and large‐scale dynamic process. Specifically, increased cloud water/ice content with this scheme reduces surface shortwave radiation, and consequently surface heat fluxes and evapotranspiration. This, in turn, dampens the large‐scale thermal effect of the TP and weakens the exaggerated monsoon circulation and low‐level moisture convergence. It is this large‐scale dynamic process that contributes the most (∼70%) to the wet bias reduction. Although this paper presents a modeling study, it highlights the cloud radiative feedback to the large‐scale dynamics and precipitation over the TP. Plain Language Summary: Despite numerous attempts to correct the overestimation of summer precipitation over the Tibetan Plateau (TP) in current global and regional climate models, the issue persists. This study applies the Gaussian Probability Density Function (GPDF) cloud fraction scheme in the Weather Research and Forecasting model at two different resolutions (0.1° and 0.05°) during a summer over the TP. The results show that the GPDF scheme significantly mitigates the precipitation overestimation, particularly in the high‐resolution modeling. We explored the physical processes, both local and remote, that contribute to this improvement. Specifically, an increase in cloudiness reduces the amount of radiation reaching the land surface. This decrease in surface radiative heating not only reduces local evaporation but also weakens the thermal effect of the TP. The latter is a major driver of the South Asian monsoon that conveys moisture to the TP, and its weakening reduces moisture convergence over the TP. Both the decreases in local evaporation and remote moisture convergence contribute to the alleviation of the precipitation overestimation, and the latter plays a dominant role. These findings provide a unique perspective for reducing the wet bias over the TP, focusing on the surface available energy and associated remote moisture processes. Key Points: The use of the Gaussian Probability Density Function cloud fraction scheme in high resolution greatly reduces wet bias over the Tibetan Plateau (TP) during summerMore cloud water/ice with the scheme lessens TP's thermal effect, causing a weaker South Asian monsoon and moisture convergenceWet bias reduction is mainly governed by the decrease in remote moisture rather than local evapotranspiration [ABSTRACT FROM AUTHOR]

Simple Summary: Freshwater ecosystems are embedded in terrestrial ecosystems to form an integral whole. In the context of global climate change, freshwater ecosystems may be irreversibly negatively affected; thus, aquatic organisms dependent on freshwater ecosystems are severely affected. However, terrestrial life may also experience unexpected crises due to the collapse of freshwater ecosystems, and we know very little about the relationship between terrestrial life and freshwater ecosystems. Therefore, we conducted our research on the Tibetan Plateau, an area with a dense distribution of lakes. We analyzed the relationship between the number of Tibetan antelopes (an ungulate mammal distributed in the region) and the number of lakes, and the distribution of the terrain and vegetation around the lake. Our results indicated that a greater abundance of Tibetan antelopes was associated with larger lakes, flatter terrain, and proximity to lakes, which may all be factors that affect the survival of this species. Our study suggests that lakes may provide a better habitat for ungulates in such a fragile ecosystem, including a different predation risk and more food resources, and this also provides a new research idea for the study of multi-species coexistence on the Tibetan Plateau. The influence of freshwater ecosystems on terrestrial taxa in high-altitude regions with challenging access, such as the Tibetan Plateau, remains inadequately understood. This knowledge gap is particularly significant due to the fragility of these ecosystems, characterized by low primary productivity. Ungulates, in particular, may exhibit high sensitivity to even minor alterations in plant availability, potentially stemming from global climate change. Consequently, the investigation of these ecosystems may offer valuable insights into addressing future challenges posed by climate change. Here, to fill this knowledge gap, we explore the relationship between lakes and Tibetan antelopes in an even more vulnerable region, the Tibetan Plateau. We found that the Tibetan antelope population was higher in areas with larger lakes, and where the terrain near the lakes was flatter. At the same time, vegetation cover and plant diversity were higher near the lake compared to areas farther away from the lake. This phenomenon can be elucidated by the fact that lakes offer Tibetan antelopes a richer food supply and reduced predation risk. Our study provides new perspectives for researchers to explore the cross-ecosystem impacts of climate change. [ABSTRACT FROM AUTHOR]

Vegetation is the most vulnerable component of terrestrial ecosystems to climate change. In recent decades, there has been a significant warming and humidification trend in the Tibetan Plateau. It is crucial to study and analyze the impact of these changes on the ecosystem and their future trends for protecting the Tibetan Plateau's ecosystem. This study collected and analyzed climate (temperature, precipitation) data and vegetation index data (the normalized difference vegetation index (NDVI) and the leaf area index (LAI)), as well as data from significance tests combined with Mann–Kendall tests and Sen's slope estimation. The effects of temperature and precipitation factors on vegetation indices were revealed, leading to a multiple regression model predicting NDVI and LAI value changes under climate change from 2021 to 2100. The results indicate a general increase in temperature and precipitation levels across the Tibetan Plateau between 2000 and 2020. The climate experienced a clear pattern of warming and moist conditions, with the southeast region experiencing warmer and wetter conditions, and the northwest region experiencing drier and colder conditions. The trends of the LAI and NDVI values of the Tibetan Plateau indicated a general increase, with a gradual decline from the southeast to the northwest. Precipitation and temperature were differentially correlated with the NDVI and LAI values across various regions of the plateau. Between 2021 and 2100, the Tibetan Plateau is expected to experience year-on-year increases in both precipitation and temperature levels. However, the increase in precipitation was found to be less significant than that of the climate and, comparatively, smoother. There is a certain correlation between the NDVI and LAI values, and the changes in temperature and precipitation. The variations of both are more influenced by temperature than precipitation, with an overall increasing trend observed over the years, which is also quite evident. This study could serve as a scientific foundation and a point of reference for monitoring vegetation changes over a long period of time on the plateau, as well as for the planning and execution of ecological development in the Tibetan Plateau. [ABSTRACT FROM AUTHOR]

Reliable precipitation simulation over the Tibetan Plateau (TP) remains a challenge, manifested by a prominent systematic wet bias in the warm season. Previous studies have generally neglected the potential linkage between surface radiation energy budget and precipitation bias. Prevalent scattered cumulus and thunderstorms over the TP in summer strongly influence surface radiation. A cloud fraction scheme considering subgrid temperature and humidity fluctuations is implemented in the WRF model and tested for a month‐long simulation. It is found that the scheme better reproduces the surface solar radiation compared to a default cloud fraction scheme in the WRF model. Using abundant surface observations, we find that overestimation of the downward surface shortwave radiation (DSSR) would lead to wet bias. DSSR overestimation contributes to higher surface temperature and larger evaporation and enhanced atmospheric instability, which favor more simulated convective precipitation. The study suggests that a better simulation of clouds and surface radiation would benefit precipitation simulation over the plateau. Plain Language Summary: Summer precipitation over the Tibetan Plateau (TP) is generally overestimated in general circulation models as well as regional weather forecasts and climate models. The prevailing "popcorn‐like" clouds over the TP in summer would strongly impact surface radiation. Considering the potential linkage between surface radiation energy budget and precipitation bias, a statistical cloud fraction and subgrid condensation scheme (GS‐PDF scheme) is implemented in the WRF model and tested for a month‐long simulation. The GS‐PDF scheme better captures clouds over the TP with more mid‐low cloud water (ice) than the default Xu‐Randall scheme. Increased mid‐low cloud water in the GS‐PDF scheme reduced simulated downward surface shortwave radiation, reduced simulated surface temperatures, atmospheric instabilities and convective precipitation, leading to alleviated wet bias over the TP. This study suggests that better simulations of cloud and surface radiation would be beneficial for simulations of hydrological cycles over the TP. Key Points: A new cloud macrophysics scheme considering subgrid temperature and humidity fluctuations is implemented in the WRF modelThe new macrophysics scheme reduced simulated downward surface shortwave radiation, surface temperatures and atmospheric instabilitiesA better simulation of clouds and surface radiation would benefit precipitation simulation over the Tibetan Plateau [ABSTRACT FROM AUTHOR]

The onset date of the South China Sea (SCS) summer monsoon (SCSSM) and the generation time of the first tropical cyclone (TC) over the Bay of Bengal (BoB) during late April and early June were significantly correlated with a correlation coefficient of 0.58 during 1979–2020. The composite analysis found that under the impact of BoB TCs, an enhanced southwesterly low‐level flow transported abundant moisture from the BoB to the northern SCS. Besides, the diabatic heating related to TC convection stimulated an anticyclonic anomaly in the upper troposphere over the southern Tibetan Plateau, which was conducive to the enhancement and expansion of the South Asian high (SAH) over the Indo‐China Peninsula. The stronger easterly outflows from the eastern periphery of the SAH overlapped with low‐level water vapor convergence over the northern SCS, enhancing the development of monsoon convection. Thus, more condensation heating warmed the tropospheric atmosphere and reversed the meridional temperature gradient over the SCS, implying the SCSSM onset. [ABSTRACT FROM AUTHOR]

A non-motile, Gram-staining-negative, orange-pigmented bacterium called herbae pc1-10T was discovered in Tibet in the soil around Pyrola calliantha H. Andres' roots. The isolate thrived in the temperature range of 10–30 °C (optimal, 25 °C), pH range of 5.0–9.0 (optimum, pH = 6.0), and the NaCl concentration range of 0–1.8% (optimal, 0%). The DNA G+C content of the novel strain was 37.94 mol%. It showed the function of dissolving organophosphorus, acquiring iron from the environment by siderophore and producing indole acetic acid. Moreover, the genome of strain herbae pc1-10T harbors two antibiotic resistance genes (IND-4 and AdeF) encoding a β-lactamase, and the membrane fusion protein of the multidrug efflux complex AdeFGH; antibiotic-resistance-related proteins were detected using the Shotgun proteomics technology. The OrthoANIu values between strains Chryseobacterium herbae pc1-10T; Chryseobacterium oleae CT348T; Chryseobacterium kwangjuense KJ1R5T; and Chryseobacterium vrystaatense R-23566T were 90.94%, 82.96%, and 85.19%, respectively. The in silico DDH values between strains herbae pc1-10T; C. oleae CT348T; C. kwangjuense KJ1R5T; and C. vrystaatense R-23566T were 41.7%, 26.6%, and 29.7%, respectively. Chryseobacterium oleae, Chryseobacterium vrystaatense, and Chryseobacterium kwangjuense, which had 16S rRNA gene sequence similarity scores of 97.80%, 97.52%, and 96.75%, respectively, were its closest phylogenetic relatives. Chryseobacterium herbae sp. nov. is proposed as the designation for the strain herbae pc1-10T (=GDMCC 1.3255 = JCM 35711), which represented a type species based on genotypic and morphological characteristics. This study provides deep knowledge of a Chryseobacterium herbae characteristic description and urges the need for further genomic studies on microorganisms living in alpine ecosystems, especially around medicinal plants. [ABSTRACT FROM AUTHOR]

Continued climate warming and precipitation fluctuations are expected to further affect aboveground net primary productivity (ANPP) across alpine grasslands, with associated implications for ecosystem functions. The spatial and temporal variability of ANPP in Tibetan Plateau (TP) grasslands and its response to temperature and precipitation were investigated in this study, based on the ANPP estimated by means of ensemble analysis of multiple machine learning models. First, the response of the spatial distribution of ANPP to variations in the precipitation gradient was nonlinear and showed an S-shaped growth pattern, which could be divided into four stages (stationary, rapid growth, slower growth, and saturation) corresponding to arid (mean annual precipitation (MAP) < 250 mm), semiarid (250 mm < MAP < 450 mm), semihumid (450 mm < MAP < 650 mm) and humid (MAP > 650 mm) precipitation regimes, respectively. Second, regional precipitation regimes affected the sensitivity of ANPP's interannual variability to temperature and precipitation; ANPP is more sensitive to temperature in wetter areas than in dryer areas of the TP region. The results of our study suggest that in the region of Tibetan Plateau, the response of grassland ANPP variation to climate was constrained by the background precipitation regimes. [ABSTRACT FROM AUTHOR]

Litter humification plays a crucial role in organic matter formation and soil carbon sequestration in forest ecosystems. However, how forest gap formation and gap size variation affect the litter humification process remains poorly understood. An eight-year in situ decomposition experiment was conducted to evaluate humus accumulation (humic substances, humic and fulvic acid), humification degrees, humification ratios and optical properties (ΔlogK, E4/E6 and A600/C) of Minjiang fir (Abies faxoniana Rehder & E.H.Wilson) twig litter in four gap size treatments in an alpine primitive forest on the eastern Tibetan Plateau, including (1) closed canopies, (2) small gaps (38–46 m2 in size), (3) medium gaps (153–176 m2 in size),and (4) large gaps (255–290 m2 in size). The results indicated that the accumulation of humic substances and humic acid in the closed canopies was significantly higher than that in the large gaps during the first two years of decomposition. After eight years of decomposition, there were significant differences in the humic substance accumulations and the values of ΔlogK and A600/C among the different gap sizes. Furthermore, twig litter was humified in the first 2 years of incubation, and the net accumulation of humic substances was ranged from −23.46% to −44.04% of the initial level at the end of the experiment. The newly accumulated humus was young (mature (type Rp) humus) and transformed to mature (type A) humus after 4–6 years of decomposition. Partial least squares (PLS) suggested that gap-induced variations in twig litter chemistry (i.e., contents of cellulose, lignin, nitrogen (N) and phosphorus (P), and the ratios of C/N N/P) mainly drove the process of twig litter humification. Our results presented here denote that the formation of forest gaps retard twig litter humification process, which might be detrimental to carbon sequestration in the alpine forest ecosystems. [ABSTRACT FROM AUTHOR]

Trends of precipitation over the Tibetan Plateau (TP) are characterized by a north‐south dipole pattern, and the role of local mesoscale systems, TP vortices (TPVs), remains ambiguous. This work reports that the north‐south dipole pattern trends in the TPVs‐associated precipitation have experienced an interdecadal shift in the last two decades, that is, increases in northern TP and decreases in southern TP first and then varies opposite trends, which greatly contributes to the similar interdecadal shift in TP precipitation trends. Furthermore, the causes of changes in TPV frequency are explored from the perspective of lower troposphere conditions. We find that the lower‐level winds, that is, zonal winds over the TP and meridional winds across the northwestern TP boundary, are responsible for the regionally different variations in TPV frequency. The variations in Indian Ocean Dipole are suggested to contribute to the changes in lower‐level winds over the TP. Plain Language Summary: Precipitation over the Tibetan Plateau (TP) significantly affect local and downstream water resources, which generally presents dipole pattern trends, that is, opposite precipitation trends in the northern TP (NTP) and in southern TP (STP). However, the physical processes of the variations in TP precipitation, especially the roles of local mesoscale systems, TP vortices (TPVs), are not yet clear. In this work, dipole pattern variations are found in TPVs‐associated precipitation, which experienced an interdecadal shift in the last two decades, that is, increases in NTP and decreases in STP first and then varies opposite trends. The interdecadal shift in the TPVs‐associated precipitation trends greatly contributes to the interdecadal shift in the TP precipitation trends. Furthermore, the causes of variations in TPV frequency are explored, and find that the changes in zonal winds over the TP and meridional winds across the northwestern TP boundary are closely related to the regionally different variations in TPV frequency. Subsequently, the changes in the sea surface temperature of India Ocean are demonstrated to be responsible for the wind variations. Key Points: North‐south dipole pattern precipitation trends over the Tibetan Plateau (TP) have experienced an interdecadal shift in the last two decadesChanges in TP vortices (TPVs) contribute to the interdecadal shift in the TP precipitation trend patternSea surface temperature of India Ocean is responsible for variations in lower‐level winds, prompting changes in TPVs [ABSTRACT FROM AUTHOR]

The Tibetan partridge (Perdix hodgsoniae) is a widely distributed endemic species in high-altitude areas across the Tibetan Plateau where the hypoxia, lower temperature and high ultraviolet radiation are pivotal factors influencing survival. However, the underlying genetic adaptation of the Tibetan partridge to extreme environments remains uncertain due to limited genomic resources. Similarly, the phylogenetic position of Perdix within Phasianidae remains controversial due to lacking information. Consequently, we de novo assembled and annotated the whole genome of the Tibetan partridge. The genome size was 1.15 Gb with contig N50 of 3.70 Mb. A total of 202.30 Mb (17.61%) repetitive elements and 445,876 perfect microsatellites were identified. A total of 16,845 functionally annotated protein-coding genes were identified in the Tibetan partridge. Genomic phylogenetic analysis across 30 Galliformes species indicated a close relationship between Perdix and typical pheasants composed of Chrysolophus , Symaticus , Phasianus , Crossopilon , and Lophura. However, the phylogenetic relationship of (Perdix + (Chrysolophus + (Syrmaticus + other pheasants))) was different from those of (Perdix + (Syrmaticus + (Chrysolophus + other pheasants))) in previous studies. Comparative genomic results identified NFKB1 and CREBBP positively selected genes related to hypoxia with 3 and 2 Tibetan partridge-specific missense mutations, respectively. Expanded gene families were mainly associated with energy metabolism and steroid hydroxylase activity, meanwhile, contracted gene families were mainly related to immunity and olfactory perception. Our genomic data considerably contribute to the phylogeny of Perdix and the underlying adaptation strategies of the Tibetan partridge to a high-altitude environment. [ABSTRACT FROM AUTHOR]

Identifying the factors influencing wetland variations is crucial for understanding the relationship of climate change with wetland conservation and management. The wetland distribution is associated with multiple variables, and the interactions among these variables are complex. In this study, we aim to explore an interpretable and quantitative analysis of factors related to wetland spatiotemporal variations on the Tibetan Plateau (TP). By combining SHapley Additive exPlanations with a spatially stratified heterogeneity model, we propose a locally explained stratified heterogeneity (LESH) model that well reveals the effects of multiple variable interactions on the spatiotemporal variations of wetlands. The results show that topographic variables are the most important variables related to the spatial distribution of wetlands on the TP, and climatic variables are the most relevant factors for the increase in the wetland area on the TP from 2015 to 2019. In addition, the interactions among multiple variables strongly influence wetlands on the TP. Among them, when other geographic variables interact with the evaporation variable, its explanatory power on wetland distribution is significantly increased. Knowledge of wetland distribution determinants can help us understand the evolution of wetlands and the impacts of climate change on wetland variations. [ABSTRACT FROM AUTHOR]

Qinghai-Tibet Plateau lakes are important carriers of water resources in the 'Asian's Water Tower', and it is of great significance to grasp the spatial distribution of plateau lakes for the climate, ecological environment, and regional water cycle. However, the differences in spatial-spectral characteristics of various types of plateau lakes, and the complex background information of plateau both influence the extraction effect of lakes. Therefore, it is a great challenge to completely and effectively extract plateau lakes. In this study, we proposed a multiscale contextual information aggregation network, termed MSCANet, to automatically extract Plateau lake regions. It consists of three main components: a multiscale lake feature encoder, a feature decoder, and a Multicore Pyramid Pooling Module (MPPM). The multiscale lake feature encoder suppressed noise interference to capture multiscale spatial-spectral information from heterogeneous scenes. The MPPM module aggregated the contextual information of various lakes globally. We applied the MSCANet to the lake extraction of the Qinghai-Tibet Plateau based on Google data; additionally, comparative experiments showed that the MSCANet proposed had obvious improvement in lake detection accuracy and morphological integrity. Finally, we transferred the pre-trained optimal model to the Landsat-8 and Sentinel-2A dataset to verify the generalization of the MSCANet. [ABSTRACT FROM AUTHOR]

Plant pathogens are often hypothesized to promote species coexistence by generating conspecific negative density dependence (CNDD). However, the relative importance of fungal versus oomycete pathogens in maintaining plant species coexistence and community composition remains unresolved, despite their recognized effects on plant performance. Here, we use fungicide application to investigate how fungal versus oomycete pathogens affect plant species coexistence in an alpine meadow. We found that the severity of foliar fungal disease was density‐dependent at both intra‐ and interspecific levels. Fungal pathogen‐exclusion treatment successfully decreased the severity of foliar fungal diseases, with no detectable effects on root colonization by arbuscular mycorrhizal fungi or on soil chemical properties. Fungal pathogens were important factors shaping CNDD across 25 coexisting plant species. Exclusion of fungal pathogens significantly reduced plant species richness and Shannon's evenness. Treatments that excluded fungal pathogens also led to significant shifts in plant community composition toward more Poaceae and Cyperaceae. These results indicate that fungal pathogens, especially those affecting aboveground plant parts, may play a larger role in maintaining species coexistence and shaping community composition than has been previously recognized. [ABSTRACT FROM AUTHOR]

The evolutions of climate‐sensitive lakes on the Tibetan Plateau's endorheic basin exhibited lake shrinkage before the mid‐1990s, but widespread and rapid lake expansions ever since. However, the quantitative contribution of glacier meltwater to lake changes, and the exact mechanisms behind its dominant drivers remain elusive. Here, a comprehensive examination of glacier mass balance since ∼1975 reveals that excess glacier meltwater compensated for net lake volume loss by 21% ± 5% during its contraction period 1975–1995, whereas promoted net volume gain by 9% ± 1% during expansion period 1995–2020 and by 17% ± 2% over the entire period 1975–2020. Further analyses reveal that the interdecadal variations of sea surface temperatures in the Atlantic, Pacific, and Indian Oceans favor a net moisture inflow to the Tibetan Plateau, leading to increased precipitation since 1995 relative to 1970s–1995, which effectively elucidates the climatic process causing rapid lake volume expansion in the endorheic basin. Plain Language Summary: Most of the lakes over the Tibetan Plateau are located in its endorheic basin in the Inner Plateau, forming a 700,000 km2 landlocked drainage area with an average elevation of over 4,000 m above sea level. An updated survey using comprehensive historic satellite images reveals a change in the trends of the number of lakes formed, their area, lake level, and volume over the past half a century, 1975–2020. The number and area of the lakes shrunk in 1975–1995, followed by an expansion in 1995–2020. Here, we elucidate the origin of this climatic change and conclude that excess glacier meltwater contributed to lake water balance by 21% during the lake contraction period 1975–1995. During the lake rapid expansion period of 1995–2020, mountain glaciers wasted at twice the rate during the earlier period; however, the contribution fraction remains smaller at 9%. The pattern of precipitation was the dominant driver of this multidecadal trajectory in lake change trends. The increases in precipitation since 1995 relative to 1970s−1995 was mainly induced by increased net moisture, which was attributable to interdecadal variations of sea surface temperature in the Atlantic, Pacific, and Indian Oceans. Key Points: Glacier melt compensated for net lake volume loss by 21% in 1975–1995 and promoted net lake volume gain by 9% in 1995–2020Glacier meltwater contributing to lake water gain mainly occurred in the southern Inner Tibetan PlateauTeleconnection of interdecadal sea surface temperature changes in three oceans was associated with increased precipitation and lake expansion [ABSTRACT FROM AUTHOR]

To reduce the uncertainty of cloud feedback, models should prioritize the evaluation of cloud response to surface warming. Using International Satellite Cloud Climatology Project‐H data sets, we quantified the cloud fraction response of different cloud types to surface warming in the Tibetan Plateau (TP) and examined the performance of Coupled Model Intercomparison Project Phase 6 models in reproducing cloud response. Results showed multimodel ensemble mean (MEM) exhibited a similar pattern of total cloud fraction response with the observation but severely underestimated it over the western TP. MEM also obviously underestimated cloud fraction of optically thin cirrus (bias >15%) and had a wrong trend of −0.02% 10a−1 against observed +2.44% 10a−1. Moreover, models failed to reproduce extensive negative response of optically thick clouds and exhibited significant underestimation for the negative response of optically thick but lower‐top clouds. Especially, models even simulated an opposite response with International Satellite Cloud Climatology Project for optically thin but lower‐top cloud (bias hit −0.4% K−1). Plain Language Summary: To reduce the uncertainty in cloud feedback, knowledge about the response of cloud fraction (as the first‐order variable impacting downwelling shortwave radiation flux) to the surface warming is an important yet poorly understood process, especially over the Tibetan Plateau (TP). This study utilized 31 years of cloud top pressure (PC)‐cloud optical thickness (PC‐τ) histograms from the International Satellite Cloud Climatology Project‐H data set to characterize cloud fraction response for different cloud types and comprehensively evaluate the performance of Coupled Model Intercomparison Project Phase 6 models in reproducing cloud response over the TP. Although multimodel ensemble mean (MEM) showed similar distribution of total cloud fraction response with observation, cloud response over the western TP was significantly underestimated. For the most frequent but less simulated optically thin high cirrus, the MEM produced consistent cloud response with the observation mainly due to the offsetting effect of regional cloud response bias. In addition, we found that optically thick but lower‐top clouds (or thin high cirrus) significantly declined (or increased) with surface warming, especially under an unstable state. Nonetheless, MEM significantly underestimated an extensive negative cloud response of optically thick clouds, especially at low‐level atmosphere. These new insights will help models reduce the uncertainty in future climate projections caused by cloud feedback. Key Points: Even if biases are partly offset, Coupled Model Intercomparison Project Phase 6 models still obviously underestimate total cloud fraction response in the western Tibetan PlateauFor more frequent but less simulated thin cirrus, models show consistent response with the observation mainly due to offsetting of the regional biasModels severely underestimate the negative response of low‐level thick clouds and invert the positive response of low‐level thin clouds [ABSTRACT FROM AUTHOR]

The north‐eastward extrusion of the Tibetan Plateau has always been under debate. The arcuate tectonic belt is located at the north‐east margin of the Tibetan Plateau and bears crucial information about the tectonic and geomorphic evolution of north‐east Tibetan Plateau. Combined with sedimentary sequence, detrital zircon U–Pb geochronology, and heavy mineral combinations, significant provenance transformation can be determined both in the south‐west and north‐east of the arcuate tectonic belt during the Eocene to Miocene. The far‐field effect of north‐eastward extrusion of the Tibetan Plateau first arrived at the south‐west of the arcuate tectonic belt during the Miocene and resulted in the angular unconformity between the Eocene Qingshuiying period and Miocene Zhangenbao Formation. Then the regional exhumation spread from south‐west to north‐east across the arcuate tectonic belt, and sedimentary hiatus developed between the Miocene Zhangenbao period and Pliocene Ganhegou period. Therefore, tectonic uplift and mountain building of the arcuate tectonic belt expanded north‐eastward during the Eogene to Neogene. This research shed new insights on the north‐eastward extrusion of the Tibetan Plateau from the coupling relationship between basin and range. [ABSTRACT FROM AUTHOR]

Palaeoglacier modelling is an important approach for reconstructing the palaeoclimate. The timing of glaciations in the central part of the Gangdise Mountains has been constrained previously, but the palaeoclimate remains unclear. In this paper, the palaeo-temperature and precipitation of the early marine isotope stage (MIS) 2, the Last Glacial Maximum (LGM), and the early Holocene were reconstructed using coupled mass balance and ice flow models. The results show that a series of temperature changes (ΔT) and precipitation factors (Fp) resulted in optimum palaeoglacial extents. The modelled palaeoglaciers during the early MIS 2, the LGM, and the early Holocene cover areas of ~18.1 km2, ~17.4 km2, and ~16.3 km2, respectively, with ice volumes of ~2.18 km3, ~1.99 km3, and ~1.95 km3, respectively. Previous studies on ice cores, pollen samples, and lake sediments were referenced to narrow the range of palaeo-temperatures and precipitations. The reconstructed temperatures during the early MIS 2, LGM, and early Holocene were constrained to 2.4–2.9 °C, 2.15–3.05 °C, and 0.95–1.5 °C lower than today, respectively. Their precipitation levels were 60–80%, 50–80%, and 100–150% of the present-day level, respectively. [ABSTRACT FROM AUTHOR]

Plant leaf stoichiometry reflects its adaptation to the environment. Leaf stoichiometry variations across different environments have been extensively studied in grassland plants, but little is known about intraspecific leaf stoichiometry, especially for widely distributed species, such as Stellera chamaejasme L. We present the first study on the leaf stoichiometry of S. chamaejasme and evaluate its relationships with environmental variables. S. chamaejasme leaf and soil samples from 29 invaded sites in the two plateaus of distinct environments [the Inner Mongolian Plateau (IM) and Qinghai-Tibet Plateau (QT)] in Northern China were collected. Leaf C, N, P, and K and their stoichiometric ratios, and soil physicochemical properties were determined and compared with climate information from each sampling site. The results showed that mean leaf C, N, P, and K concentrations were 498.60, 19.95, 2.15, and 6.57 g kg−1; the average C:N, C:P, N:P, N:K and K:P ratios were 25.20, 245.57, 9.81, 3.13, and 3.21, respectively. The N:P:K-ratios in S. chamaejasme leaf might imply that its growth is restricted by K- or K+N. Moreover, the soil physicochemical properties in the S. chamaejasme-infested areas varied remarkably, and few significant correlations between S. chamaejasme leaf ecological stoichiometry and soil physicochemical properties were observed. These indicate the nutrient concentrations and stoichiometry of S. chamaejasme tend to be insensitive to variations in the soil nutrient availability, resulting in their broad distributions in China's grasslands. Besides, different homeostasis strength of the C, N, K, and their ratios in S. chamaejasme leaves across all sites were observed, which means S. chamaejasme could be more conservative in their use of nutrients improving their adaptation to diverse conditions. Moreover, the leaf C and N contents of S. chamaejasm were unaffected by any climate factors. However, the correlation between leaf P content and climate factors was significant only in IM, while the leaf K happened to be significant in QT. Besides, MAP or MAT contribution was stronger in the leaf elements than soil by using mixed effects models, which illustrated once more the relatively weak effect of the soil physicochemical properties on the leaf elements. Finally, partial least squares path modeling suggested that leaf P or K contents were affected by different mechanisms in QT and IM regions, suggesting that S. chamaejasme can adapt to changing environments by adjusting its relationships with the climate or soil factors to improve its survival opportunities in degraded grasslands. [ABSTRACT FROM AUTHOR]

The Xizang plateau frog, N. parkeri (Anura: Dicroglossidae), is endemic to the Tibetan Plateau, ranging from 2,850 to 5,100 m above sea level. The present study explores physiological and biochemical adaptations to high altitude in this species with a particular emphasis on parameters of hematology, oxidative stress, and antioxidant defense in adult and juvenile N. parkeri collected from high (4,600 m a.s.l) and low (3,400m a.s.l) altitudes. Hematological results showed that hemoglobin concentration ([Hb]), hematocrit (Hct), and red blood cell (RBC) counts were significantly higher in high-altitude N. parkeri. Highaltitude juveniles had lower RBC sizes than low-altitude juveniles. Higher levels of GSH and GSSG were indicated only in juveniles from high altitude, not in adults. High-altitude individuals also showed lower oxidative damage, assessed as malondialdehyde (MDA) and carbonyl groups (CG) in the liver. High-altitude adults also showed higher activities of superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPX), and glutathione-S-transferase (GST) as well as total antioxidant capacity (T-AOC) in the liver as compared to low-altitude adults. Moreover, higher GPX activity and T-AOC were observed in the heart and brain of high-altitude adults. Liver CAT, GPX, and T-AOC showed significant increases in high-altitude juveniles. Vitamin C content was also higher in the heart of high-altitude frogs compared to low-altitude individuals. In summary, the highaltitude population of N. parkeri showed more robust hematological parameters, less oxidative damage, and stronger antioxidant defenses than the low-altitude population, all contributing to increased protection for survival in high-altitude environments. [ABSTRACT FROM AUTHOR]

The East Kunlun Orogenic Belt (E‐KOB) of the northern Tibetan Plateau is an accretionary orogenic belt, which has experienced complicated tectonic evolutionary processes of the Proto‐ to Palaeo‐Tethys Ocean. The Muztagh‐Buqingshan‐Anemaqen ophiolitic mélange zone (MBAM) is an accretionary complex related to the northward subduction of the Tethyan Ocean. Numerous intrusions outcropped in MBAM have witnessed the long‐term subduction‐accretionary process and thus site the key to comprehending the tectonic evolution of the E‐KOB, as well as the Tethyan Ocean. In this study, petrological, geochronological, and geochemical studies of the Marzheng diorites in the MBAM were carried out to explore the Early Palaeozoic tectonic evolution of the E‐KOB. Zircon U–Pb dating analysis suggests that the diorites were formed in the Early Ordovician at ca. 470 Ma. Furthermore, the εHf(t) values (5.3–14.1), Mg# values (39.7–51.2), and Nb/Ta (12.8–14.8), Zr/Hf (33.8–44.8), and Lu/Yb (0.15–0.16) ratios are generally close to those of depleted mantle‐derived rocks and the diorites were originated from a depleted asthenosphere mantle source. In addition, these diorites are characterized by enriched light rare earth elements (LREEs) (La and Nd) and depleted high‐field‐strength elements (HFSEs) (Nb, Ta, P, and Ti), similar to the fingerprints of arc‐related gabbroic‐dioritic rocks. This is also consistent with their high H2Omelt (6.0–8.3%) and oxygen fugacity (logfO2 = −14.3 to −13.5) features, indicating that they were formed in a subduction‐related setting. Our new investigations suggest that the Proto‐Tethys Ocean in the East Kunlun was still actively subducting northward during the Early Ordovician. [ABSTRACT FROM AUTHOR]

Palaeoflood records have provided the extended perspective required to understand linkages between extreme floods and climate variability. During our palaeo‐hydrological investigations, two units of palaeoflood slackwater deposits (SWD) were found on the river banks in the Maqu‐Oula reach along the mainstream of the Yellow River on the northeast (NE) Tibetan Plateau. A series of samples were taken from the sediment profiles at Taiwuruo (TWR) and Daerqiong (DEQ) sites for laboratory analysis. Grain‐size distribution and micro‐morphological characteristics of quartz grains indicate that these well‐sorted SWD units were derived from the suspended sediment load in floodwater. They have recorded two episodes of overbank flooding in the Yellow River source area. Using the optically stimulated luminescence (OSL) dating technique, the first episode of overbank flooding was dated to 13.6–13.0 ka and correlated with the Bølling–Allerød warm interval of the last deglaciation. The second episode occurred at 11.0–10.0 ka, that is, the early Holocene. In a warm‐humid climate, these overbank flooding episodes may have resulted from the accelerated melting of mountain glaciers and snow over the headwaters of the alpine and subalpine regions on the NE Tibetan Plateau. These results are important in facilitating an in‐depth understanding of the hydro‐climatic response of the Tibetan Plateau to global climate warming occurring presently. [ABSTRACT FROM AUTHOR]

The roles of lower-crustal flow and upper-crustal shortening on the growth of the SE Tibetan Plateau remain under debate, which calls for a knowledge about regional exhumation history. We analyzed apatite fission track ages of modern sediments from both the east and west sub-catchments along the Anninghe River, in the SE plateau. We obtained four age components, with peaks a bit younger in the east than in the west. Combing the asymmetric topography with higher relief in the east, we concluded a non-uniform exhumation pattern. The components are at the Oligocene, late-Miocene, Pliocene, and Pleistocene, mostly consistent with the timing for changes in catchment-wide erosion rates as indicated by the inverse erosion history. We concluded that, in addition to the late-Miocene lowercrustal flow and Oligocene upper-crustal shortening, the landscape in the SE plateau might also be under influences of fault strike-slip transfer and drainage network reorganization. Plain Language Summary Different models that have been proposed to explain how the topography in the SE Tibetan Plateau grows predict different histories for regional uplift and/or erosion. Lower-crust flow was suggested to drive rapid surface uplift since 10-15 Ma, while findings of earlier fault thrusting implies the effects of upper-crust shortening. To test these models, we analyzed detrital ages of sediments from both the east and west sub-catchments along the modern Anninghe River, in the SE plateau. We obtained the Oligocene, late-Miocene, Pliocene, and Pleistocene age components, all of which are with peaks a bit younger in the east than in the west. Considering that the topography is also somewhat steeper in the east, we concluded a spatially non-uniform erosion pattern since the middle Cenozoic. The four age components reveal multistage erosion processes in the Anninghe catchment and thus indicate multiple forces to drive topographic growth in the SE plateau. [ABSTRACT FROM AUTHOR]

Precipitation over the Tibetan Plateau (TP) significantly affects both the local ecology and the downstream water resources. In this study, it is found that there exists an increasing precipitation trend over the northern TP but not in the southern TP, which is interpreted from the perspective of the activities of Tibetan Plateau vortices (TPVs). In the context of recent warming over the TP, the increasing rate of genesis frequency of TPVs over the northern TP is remarkably larger than that over the southern TP, which is responsible for different precipitation trends in the northern and southern TP, respectively. That is, the most significant warming over the TP appears in the upper troposphere, which intensifies the 200 hPa westerly jet north of the TP, hereby produces more favorable conditions for the genesis of TPVs over the northern TP than over southern TP, and contributes to regional difference in precipitation trends. Plain Language Summary Precipitation over the Tibetan Plateau (TP) significantly affects the local ecology and the downstream water resources. In recent decades, significant warming trend is observed over the TP. It is found that the precipitation trends over the TP show robust regional differences in the warming context, with the causal physical process being not yet clear. Given the Tibetan Plateau vortices (TPVs) are important rainfall triggers over the TP, the regionally different precipitation trends over the TP are interpreted from the perspective of TPVs. Here, we show that warming over the TP causes regionally different increases in the genesis frequency of TPVs by modulating the upper-level westerly jet, and hereby contributes to the regional difference in precipitation trends over the TP. [ABSTRACT FROM AUTHOR]

The Mesozoic–Cenozoic Zheduo–Gongga Massif, eastern Songpan–Ganze Terrane, can provide important clues for the crustal evolution in response to syn‐ and post‐orogeny. Here, we document petrological and geochemical characteristics of Early Jurassic granites (181.0 ± 2.2 Ma) within the massif along the Xianshuihe Fault in the eastern Tibetan Plateau. The granites have high contents of SiO2, Na2O + K2O, FeOT/MgO, 10,000 × Ga/Al, REE (except Eu) and HFSE (e.g., Nb, Ta, Zr, Hf), low CaO, TiO2, P2O5 and negative Eu, Sr, and Ba anomalies. Zircon REE shows a similar pattern with the whole‐rock REE. Our new data demonstrate weakly peraluminous A‐type affinity with A/CNK >1.0 and alkali‐calcic, ferroan features. Zircon saturation temperatures and geochemical features (e.g., high SiO2 and low MgO contents, high Rb/Ba and Rb/Sr ratios) indicate that the granites resulted from high‐temperature (>800°C) partial melting of Triassic flysch rocks in relatively shallow crust (<500 MPa or <20 km). Zircon εHf(t) values range from 0.55 to 2.91 and the corresponding two‐stage TDMC are older than the neighbouring Kangding complex and Yangtze margin, implying possible contribution of mantle materials to the parent magma. Considering the tectonic events and the regional geology, the magma was generated in a post‐collisional setting, which was possibly driven by the upwelling of hot mid–lower crustal materials due to the break‐off of subducted Palaeo‐Tethys Ocean slab. Under this situation, the magma may move upwardly into the pre‐existing Xianshuihe Fault during the post‐collisional extension of the thickened crust. Thus, slab break‐off played a key role in the genesis of the Zheduo–Gongga Massif studied herein. [ABSTRACT FROM AUTHOR]

As the largest inland basin in the northeastern Tibetan Plateau, Qaidam Basin has traditionally been thought of as the key region to study the Cenozoic climatic changes in the plateau; however, the information from a palaeobotanic respect is still lacking because of the paucity of the fossil plants. Fossil fruits and foliage of Ailanthus (Simaroubaceae) are reported from the Oligocene Shangganchaigou Formation in the northwestern Qaidam Basin, Qinghai Province, China. All the characters suggest that the fossil materials should be assigned to A. confucii, which is one widely distributed fossil species in the Cenozoic, regarded as the analogue of extant A. altissima. Current materials represent the first fossil record of Simaroubaceae in the northern Tibetan Plateau. Based on the climate requirements of the living A. altissima, the ranges of mean annual temperature (MAT) and mean annual precipitation (MAP) reflected by current fossils from Qaidamare 6.9–17.0°C, and 376–1,383 mm, respectively, compared with the current climate at the fossil site with MAT of −1.03°C and MAP of 60.5 mm. The results indicate that the climate conditions of the fossil site during the Early Oligocene were much warmer and more humid than that of the current. We hereby suggest the warm and moist air could approach the northwestern Qaidam and to accommodate the ecological environment in Early Oligocene. [ABSTRACT FROM AUTHOR]

In this study, we analyze the relationships between summer afternoon low cloud cover and environmental conditions over the Tibetan Plateau (TP). Using in situ measurements, satellite data, and reanalysis, and based on theoretical analysis, we find that there is stronger thermal turbulence, lower temperature, and higher frequency of low cloud formation for the same surface relative humidity over the eastern and central TP compared with eastern China. With the same sensible heat flux, decreased air density enhances buoyancy flux, which increases the planetary boundary layer height and moisture vertical transport. At the same time, with the same near‐surface relative humidity, lower temperature over the TP decreases the lifting condensation level, which increases the probability of the air parcel reaching this level. Compared to the low‐elevation region in eastern China, these two mechanisms enhance low cloud occurrence in the afternoon over the TP. Plain Language Summary: Previous studies suggested that planetary boundary layer processes play an important role in the formation of more low clouds in the afternoon over the Tibetan Plateau (TP). However, detailed mechanisms for the differences in low cloud occurrence in the afternoon over the TP versus eastern China (low‐elevation region) remain unclear. Using in situ measurements, satellite data, and reanalysis, and based on theoretical analysis, we first quantify the more frequent low cloud occurrence over the TP, and then propose two mechanisms: (i) compared to eastern China, in the afternoon over the TP, the lower near‐surface temperature results in a lower height where condensation occurs (given the same relative humidity), and (ii) the lower air density (given the same surface sensible heat flux) results in a larger buoyancy flux, leading to a deeper boundary layer. These two mechanisms work together to increase cloud formation in the afternoon over the TP. Key Points: There are more summer afternoon low clouds over the Tibetan Plateau (TP) than over eastern China as a result of two mechanismsCompared to eastern China, with the same relative humidity, lower temperature over the TP results in a lower lifting condensation levelWith the same surface sensible heat flux, lower air density over the TP results in a larger buoyancy flux and a deeper boundary layer [ABSTRACT FROM AUTHOR]

The Xianshuihe Fault Belt (XSF), along which the syntectonic Zheduoshan batholith was emplaced, has great significance for the reconstruction of the tectonic framework in the eastern margin of the Tibetan Plateau. In this contribution, formation process and evolution of the XSF are discussed based on the structural deformation in the field and the geochronology of Zheduoshan batholith. The results show that the XSF current arc‐shaped protrusion to the north‐east probably was formed by a fracture of the clockwise rotation compression that extended northward to the periphery with the eastern Himalayan tectonic syntaxis as the centre. It is a complex fault belt formed by the superposition of multi‐stage structures. In the early‐stage formation and evolution of the XSF, the Oligocene‐Miocene migmatite zone and Miocene granites of the Zheduoshan batholith were emplaced. Among them, the lower limit of the XSF's initial activity time was not less than 47 Ma that was limited by the Zircon U–Pb geochronology of migmatite zone formed under the compression system. During the emplacement of Miocene granites, the XSF underwent a process from compression to sinistral strike‐slip, and the geochronology indicates that the onset of the XSF sinistral strike slip should not be less than 14 Ma. After syntectic magmatism, the XSF also experienced the shear deformation (from ductile to brittle) with sinistral kinematics. 40Ar‐39Argeochronology results show that the ductile shear deformation mainly occurred around 5.5–3.2 Ma and accompanied a staged and differential uplift from north to south. It extended to the south along the weak crustal zone of Anninghe, Daliangshan, Xiaojiang, and other faults, forming the Xianshuihe–Anninghe–Xiaojiang sinistral strike‐slip fault system on the eastern margin of the Tibetan Plateau, and large‐scale sinistral strike slip began around 5 Ma. Our new insights lay a foundation for understanding and dissecting the formation and evolution of the Tibetan Plateau eastern margin. [ABSTRACT FROM AUTHOR]

The Dadu River in the eastern Tibetan Plateau has the potential to record transient variations of tectonic uplift since the Late Cenozoic. In this study, we extracted bedrock channels of the Dadu River drainage basin from the 30 m ASTER digital elevation model. The longitudinal river profiles were then analyzed, and three generations of knickpoints were recognized via the slope area method. By solving the analytical solution of the linear transient stream power incision model, we determined a Late Cenozoic history of regional tectonic uplift. The results reveal slow pre–middle Miocene uplift rates (<0.1 mm/a) and then increased gradually to 0.33 ± 0.03 mm/a since 12–15 Ma until present. This increase of uplift rate from bedrock channel inversion is consistent with the regional findings of low‐temperature themochronology, emphasizing the potential and significance to utilize channel profiles to infer the tectonic uplift history. Plain Language Summary: Recently, numerous thermochronology studies have provided constraints on the timing of rapid denudation along the eastern Tibetan Plateau. However, the rates of denudation/uplift determined by thermochronological profiles are often given as an average since a certain time duration. Thus, it is difficult to quantify the history of the tectonic uplift and whether uplift has been uniform or varied through time. We used the linear simulation method and inverted the longitudinal river profiles to decipher the Late Cenozoic uplift history of the eastern Tibetan Plateau. The results reveal that before the middle Miocene, the uplift rate was slow (<0.1 mm/a), and it increased gradually to 0.33 ± 0.03 mm/a since 12–15 Ma until present. Key Points: Linear inversion of the longitudinal river profiles for Tibetan Plateau uplift historyIncrease of the uplift rate since 12-15 Ma, consistent with regional resultsNew evidence of the late Miocene tectonic uplift in eastern Tibet [ABSTRACT FROM AUTHOR]

Aim: Species diversity in the region of the Qinghai–Tibet Plateau has been extensively explored, whereas the distribution of genetic diversity remains poorly understood in this species‐rich area, parts of which are listed as biodiversity hotspots. In this study, we aimed to map the patterns of genetic diversity and divergence of plant species in this region, and to identify potential evolutionary hotspots for conservation planning. Location: Region of the Qinghai–Tibet Plateau (QTP). Methods: We compiled published molecular data for 60 plant species, and calculated intra‐population genetic diversity and inter‐population genetic divergence using haplotype sequences (chloroplast or mitochondrial DNA). We analysed the relationships between genetic diversity and longitude, latitude and elevation. We mapped the landscapes of genetic diversity and divergence for each species in GIS, and combined the resulting landscapes in order to identify hotspots of high genetic diversity and divergence. Results: There were no significant relationships between genetic diversity and longitude, latitude and elevation. For most species, areas characterized by high genetic diversity and divergence were located across the Hengduan Mountains. Nine evolutionary hotspots across the region of the QTP were identified. Main conclusions: The Hengduan Mountains are a remarkable hotspot of all three dimensions of biodiversity (genes, species and ecosystems), yet patterns of genetic diversity were partially incongruent with the distribution of species diversity. For example, several hotspots of genetic diversity were located on the QTP proper, which is relatively species poor. This partial geographic mismatch between species and genetic diversity highlights the need to consider both aspects in conservation programs. Our study suggests that more protected areas in the region of the QTP need to be established in order to protect genetic diversity and thus adaptive potential. [ABSTRACT FROM AUTHOR]

Qimantage Orogen as the western part of East Kunlun Mountains is located in the northeastern margin of the Tibet Plateau. In this contribution, detrital zircon age spectra combined with heavy mineral analysis of Cenozoic sediments from Qaidam Basin were applied to reveal the uplift history of Qimantage Mountains. Our results show that the Cenozoic staged uplift of the Qimantage Mountains exhibit eastward and northward uplift characteristics. From the middle Eocene to Quaternary, there are three major uplift stages for Qimantage Mountains: the first stage is from middle Eocene to late Eocene (~45–35.3 Ma). The range developed a topographic pattern of east‐high and west‐low at that time, and the uplift of the east part range at that time is significant perhaps linked to the Cenozoic uplift of Tibetan Plateau due to its significant crustal shortening. The second stage is from early Oligocene to late Miocene (~15–8 Ma). During this stage, the uplift is both significant in tectonic and topographic aspects, and the overall uplift occurred mainly in the middle and west part of Qimantage Mountains. The last stage is from late Miocene to Quaternary (~2.8 Ma to present), and the Qimantage Mountains experienced complete uplift. The provenance is mainly the northern Qimantage Mountains without sediments supplied from further south, and therefore, the Qaidam Basin became an intermontane basin geomorphically. [ABSTRACT FROM AUTHOR]

Abstract: Western disturbances (WDs) are midtropospheric to upper‐tropospheric mesoscale vortices, which typically propagate along the subtropical westerly jet stream and bring heavy rainfall to Pakistan and northern India during boreal winter. They are dynamically similar to Tibetan Plateau vortices (TPVs), which affect southwest China during spring and summer and emanate from the Tibetan Plateau. Here we propose that their similarity implies the existence of a more general group of upper‐tropospheric vortices featuring interactions with the orography of the Hindu Kush‐Himalaya‐Tibetan Plateau region. Using existing track databases for WDs and TPVs derived from ERA‐Interim reanalysis, we show that their respective occurrence frequencies are highly anticorrelated with each other through the seasonal cycle, yet both are strongly correlated with jet latitude. Our findings imply that the incidence of hazards due to WDs and TPVs is correlated on intra‐annual and interannual time scales, particularly through upper‐level baroclinicity. [ABSTRACT FROM AUTHOR]

Abstract: Quantifying the impact of climate change and human activities on grassland dynamics is an essential step for developing sustainable grassland ecosystem management strategies. However, the direction and magnitude of climate change and human activities in driving alpine grassland dynamic over the Tibetan Plateau remain under debates. Here, we systematically reviewed the relevant studies on the methods, main conclusions, and causes for the inconsistency in distinguishing the respective contribution of climatic and anthropogenic forces to alpine grassland dynamic. Both manipulative experiments and traditional statistical analysis show that climate warming increase biomass in alpine meadows and decrease in alpine steppes, while both alpine steppes and meadows benefit from an increase in precipitation or soil moisture. Overgrazing is a major factor for the degradation of alpine grassland in local areas with high level of human activity intensity. However, across the entire Tibetan Plateau and its subregions, four views characterize the remaining controversies: alpine grassland changes are primarily due to (1) climatic force, (2) nonclimatic force, (3) combination of anthropogenic and climatic force, or (4) alternation of anthropogenic and climatic force. Furthermore, these views also show spatial inconsistencies. Differences on the source and quality of remote sensing products, the structure and parameter of models, and overlooking the spatiotemporal heterogeneity of human activity intensity contribute to current disagreements. In this review, we highlight the necessity for taking the spatiotemporal heterogeneity of human activity intensity into account in the models of attribution assessment, and the importance for accurate validation of climatic and anthropogenic contribution to alpine grassland variation at multiple scales for future studies. [ABSTRACT FROM AUTHOR]

The Upper Weihe River (UP‐WHR) basin is located along the northeastern Tibetan Plateau. With the northeastward expansion of the Tibetan Plateau since the late Cenozoic, it has involved foreland propagation and undergone obvious surface uplift. In order to determine the latest differential rock uplift and river incision, longitudinal profiles for 12 major tributaries of the UP‐WHR were extracted. Among them, 11 tributaries display uneven profiles with “slope‐break” knickpoints, suggesting that they are in a transient state and that the change in base level caused by tectonic forces may respond to the channel evolution. In addition, channel steepness index (ksn) was calculated to detect the spatial variations of the rock uplift rate. The results show that the north margin of West Qinling (WQL) and the south Liupan Shan (LPS) areas have a high uplift rate. Reconstruction of the paleochannel indicates that the Weihe River has an average incision of 354 ± 130 m since it formed, and the south tributaries have a higher incision of 144 ± 25 m than the north. An average river erosion rate of 0.25–0.3 m/ka was estimated, the WQL has a higher erosion rate of 0.1–0.12 m/ka than Longzhong Basin and the south LPS. This uplift and river incision can be correlated to the northeastward growth of the Tibetan Plateau since the late Cenozoic. [ABSTRACT FROM AUTHOR]

Biomass allocation is an essential concept for understanding above- vs. below-ground functions and for predicting the dynamics of community structure and ecosystem service under ongoing climate change. There is rare available knowledge of grazing effects on biomass allocation in multiple zonal alpine grassland types along climatic gradients across the Northern Tibetan Plateau. We collected the peak above- and below-ground biomass (AGB and BGB) values at 106 pairs of well-matched grazed vs. fenced sites during summers of 2010–2013, of which 33 pairs were subject to meadow, 52 to steppe and 21 to desert-steppe. The aboveground net primary productivity (ANPP) was represented by the peak AGB while the belowground net primary productivity (BNPP) was estimated from ANPP, the ratio of living vs. dead BGB, and the root turnover rate. Two-ways analyses of variance (ANOVA) and paired samples comparisons with t-test were applied to examine the effects of pasture managements (PMS, i.e., grazed vs. fenced) and zonal grassland types on both ANPP and BNPP. Allometric and isometric allocation hypotheses were also tested between logarithmically transformed ANPP and BNPP using standardized major axis (SMA) analyses across grazed, fenced and overall sites. In our study, a high community-dependency was observed to support the allometric biomass allocation hypothesis, in association with decreased ANPP and a decreasing-to-increasing BNPP proportions with increasing aridity across the Northern Tibetan Plateau. Grazing vs. fencing seemed to have a trivial effect on ANPP compared to the overwhelming influence of different zonal grassland types. Vegetation links above- and below-ground ecological functions through integrated meta-population adaptive strategies to the increasing severity of habitat conditions. Therefore, more detailed studies on functional diversity are essentially to achieve conservation and sustainability goals under ongoing climatic warming and intensifying human influences. [ABSTRACT FROM AUTHOR]

The Tibetan Plateau, a unique cold and dry region recognized as the Earth's third pole, is primarily composed of alpine grasslands (>60 %). While a warming climate in the plateau is being recorded, phenology of alpine grasslands and its climatic dependencies are less investigated. This study tests the feasibility of the frequently observed Moderate Resolution Imaging Spectroradiometer (MODIS) time series (500 m, 8 days) in examining alpine phenology in the plateau. A set of phenological metrics are extracted from the MODIS Normalized Difference Vegetation Index (NDVI) series in each year, 2000-2010. A nonparametric Mann-Kendall trend analysis is performed to find the trends of these phenological metrics, which are then linked to monthly climatic records in the growing season. Opposite trends of phenological change are observed between the east and west of the plateau, with delayed start of season, peak date, and end of season in the west and advanced phenophases in the east. The correlation analysis indicates that precipitation, with a decreasing trend in the west and increasing trend in the east, may serve as the primary driver of the onset and peak dates of greenness. Temperature increases all over the plateau. While the delay of the end of season in the west could be related to higher late-season temperature, its advance in the east needs further investigation in this unique cold region. This study demonstrates that frequent satellite observations are able to extract phenological features of alpine grasslands and to provide spatiotemporally detailed base information for long-term monitoring on the plateau under rapid climate change. [ABSTRACT FROM AUTHOR]

The Tibetan Plateau in Northwest China hosts a number of hot springs that represent a biodiversity hotspot for thermophiles, yet their diversity and relationship to environmental conditions are poorly explored in these habitats. In this study we investigated microbial diversity and community composition in 13 Tibetan hot springs with a wide range of temperatures (22.1–75°C) and other geochemical conditions by using the 16S rRNA gene pyrosequencing approach. Bacteria (108–1011 copy/g; 42 bacterial phyla) in Tibetan hot springs were more abundant and far more diverse than Archaea (107–1010 copy/g; 5 archaeal phyla). The dominant bacterial phyla systematically varied with temperature. Moderate temperatures (75–66°C) favored Aquificae, GAL35, and novel Bacteria, whereas low temperatures (60–22.1°C) selected for Deinococcus-Thermus, Cyanobacteria, and Chloroflexi. The relative abundance of Aquificae was correlated positively with temperature, but the abundances of Deinococcus-Thermus, Cyanobacteria, and Chloroflexi were negatively correlated with temperature. Cyanobacteria and Chloroflexi were abundant in Tibetan hot springs and their abundances were positively correlated at low temperatures (55–43°C) but negatively correlated at moderate temperatures (75–55°C). These correlation patterns suggest a complex physiological relationship between these two phyla. Most archaeal sequences were related to Crenarchaeota with only a few related to Euryarchaeota and Thaumarchaeota. Despite the fact that microbial composition in Tibetan hot springs was strongly shaped by temperature, microbial diversity (richness, evenness and Shannon diversity) was not significantly correlated with temperature change. The results of this study expand our current understanding of microbial ecology in Tibetan hot springs and provide a basis for a global comparison. [ABSTRACT FROM AUTHOR]

To understand the differential effects of altitudinal gradient on soil inorganic nitrogen concentration and associated ammonia-oxidizingbacteria (AOB) and archaea (AOA), intact soil cores from a primary coniferous forest were in situ incubated in an alpine forest at a 3582-m altitude (A1) and transplanted to subalpine forests at a 3298-m altitude (A2) and 3023-m altitude (A3) on the eastern Tibetan Plateau. Transplant cooled the soil temperature of A2 but warmed the A3 soil temperature. Both AOA and AOB were found at the three altitudes. Compared to A1, A2 had greater AOA and AOB abundance, but A3 showed lower AOA abundance in organic soil. The AOA abundance was negatively correlated with ammonium concentration at all three altitudes, but AOB showed the reverse trend. Our results suggested that the soil nitrogen process responded differentially to soil core transplanting at different altitudes. [ABSTRACT FROM AUTHOR]