Qinghai-Tibet Plateau Region Research Articles

Linking livestock snow disaster mortality and environmental stressors in the Qinghai-Tibetan Plateau: Quantification based on generalized additive models

Livestock snow disaster occurs widely in Central-to-Eastern Asian temperate and alpine grasslands. The effects of snow disaster on livestock involve a complex interaction between precipitation, vegetation, livestock, and herder communities. Quantifying the relationship among livestock mortality, snow hazard intensity, and seasonal environmental stressors is of great importance for snow disaster early warning, risk assessments, and adaptation strategies. Using a wide-spatial extent, long-time series, and event-based livestock snow disaster dataset, this study quantified those relationships and established a quantitative model of livestock mortality for prediction purpose for the Qinghai-Tibet Plateau region. Estimations using generalized additive models (GAMs) were shown to accurately predict livestock mortality and mortality rate due to snow disaster, with adjusted-R2 up to 0.794 and 0.666, respectively. These results showed that a longer snow disaster duration, lower temperatures during the disaster, and a drier summer with less vegetation all contribute significantly and non-linearly to higher mortality (rate), after controlling for elevation and socioeconomic conditions. These results can be readily applied to risk assessment and risk-based adaptation actions.

Contribution of supra-permafrost discharge to thermokarst lake water balances on the northeastern Qinghai-Tibet Plateau

The seasonal hydrological mechanisms of two thermokarst lakes on the northeastern Qinghai-Tibet Plateau (QTP) were characterized by three-year intensive field observations and a water balance model. In three ice-free seasons, the supra-permafrost discharge contributed a mean ratio of over 170% of the precipitation. In the ice-cover seasons, the supra-permafrost discharge contribution varied between −20% and 22% of the water storage change. Results show that a large portion of the lake water storage change is because of the supra-permafrost discharge resulting from precipitation. Furthermore, a precipitation-subsurface runoff function is preliminarily identified in which the supra-permafrost discharge nonlinearly increased with more precipitation. Our results show that the recent lake expansion is linked with increasing supra-permafrost discharge dominated by precipitation. This study also suggests that we need to pay attention to the nonlinear increase of precipitation-controlled supra-permafrost discharge on the large lake expansion at the catchment scale in the QTP region, instead of only looking at the inputs (e.g., precipitation and river discharge) as shown in the previous studies.

Assessment of Atmospheric Wet Profiles Obtained from COSMIC Radio Occultation Observations over China

Atmosperic profiles derived from Constellation Observing System for Meteorology, Ionosphere, and Climate (COSMIC) radio occultation (RO) measurements make up for the lack of operational radiosonde soundings with a high spatiotemporal distribution, and their performance over China is assessed in this paper. COSMIC-retrieved atmospheric wet profiles from 2014 to 2015 are compared to the contemporaneous radiosonde profiles from 120 stations, and the vertical mean differences are used. The results show that the vertical mean biases of temperature, pressure and vapor pressure are −0.10 K, 0.69 hPa and −0.01 hPa, respectively, and that for refractivity is 0.17 N. Moreover, the temperature differences are positively correlated with station altitude, yet both the pressure and vapor pressure differences are negatively correlated with station latitude, as is the refractivity difference. The large temperature difference arising from the Qinghai-Tibet Plateau (QTP) region may be associated with the complex topography of the area and the limitations in the background model used in the COSMIC profile retrieval. Furthermore, negative refractivity bias between COSMIC and radiosonde data occurs below 5 km and is large in wet southern China, with a value of less than 1%. This result may be related to more humid conditions and super-refraction.

Carbon accumulation in Dahu Swamp in the eastern Nanling Mountains (south China) and its implications for hydroclimatic variability over the past 47 000 years

Wetlands act as persistent natural carbon sinks over long time scales. Understanding the response of these carbon reservoirs to climate change is critical to assessing potential climate feedbacks. We conducted a study of an 860‐cm‐long sediment core in Dahu Swamp in south China to determine how the carbon accumulation rate (CAR) has varied as a function of palaeohydrology and palaeoclimate over the past 47 000 years. From an orbital time scale, our results show that the CAR in Dahu Swamp is relatively low in the wet periods of Marine Isotope Stage 3 (MIS 3) (mean: 46.7 gC m−2 a−1) and MIS 1 (mean: 28.2 gC m−2 a−1), compared to the dry periods of MIS 2 (mean: 59.9 gC m−2 a−1). At centennial and millennial scales, the highest CARs of Dahu Swamp mainly occur in organic‐rich silt or clay (gyttja) layers, which correspond to the relatively dry climate (e.g. c. 48 000–41 000, c. 33 000–32 000, c. 15 800–14 900 and c. 4400–4250 cal. a BP). The CAR of Dahu Swamp is mainly controlled by local hydrological variations that are closely related to the East Asian summer monsoon (EASM) intensity, which may be co‐influenced by orbitally induced summer insolation forcing and internal feedback processes (e.g. Atlantic Meridional Overturning Circulation and El Niño/Southern Oscillation). Based on comparison with the CARs in monsoonal regions of China, we consider that precipitation may be the key factor for wetland CAR in EASM areas, whereas temperature is more important in Qinghai–Tibetan Plateau regions under Indian summer monsoon influence. The CAR of Dahu Swamp provides valuable records of wetland carbon accumulation dynamics in subtropical monsoon regions, which contradict the traditional patterns in global northern wetlands.

Semenovia torilifolia is conspecific with S. malcolmii (Apiaceae) based on morphology and molecular data

Semenovia torilifolia and S. malcolmii have been recorded to co-occur in Qinghai-Tibetan Plateau and adjacent regions. However, there were no available diagnostic characters to distinguish them. In the present study, we reconstructed the phylogeny based on nuclear ITS and ETS regions, and explored valid morphological traits through extensive fieldwork, specimen examinations and literature reviews, to determine the relationship between S. torilifolia and S. malcolmii. Our field investigations found that the morphological characters between S. torilifolia and S. malcolmii are continuous. Phylogenetic analyses revealed that S. torilifolia and S. malcolmii are nested together and formed a well-supported monophyletic taxa (90% BS, 1.00 PP) within Semenovia clade. It is thus sweeping concluded that S. torilifolia is conspecific with S. malcolmii.

SURFACE DEFORMATION MONITORING IN PERMAFROST REGIONS OF TIBETAN PLATEAU BASED ON ALOS PALSAR DATA

Abstract. The permafrost region of Qinghai-Tibet Plateau is widely distributed with the freeze/thaw processes that cause surface structural damage. The differential interferometry synthetic aperture radar (DInSAR) can detect large scale surface deformation with high precision, thus can be used to monitor the freeze/thaw processes of frozen soil area. In this paper, the surface deformation pattern of Qinghai-Tibet railway was analyzed by using the PALSAR 1.0 raw data of the ALOS satellite (L band) and 90m resolution SRTM DEM data, with the help of two-pass DInSAR method in GAMMA software, and the differential interferograms and deformation maps were obtained accordingly. Besides, the influence of temperature, topography and other factors on deformation of frozen soil were also studied. The following conclusions were obtained: there is a negative correlation between deformation and temperature, and there is a delay between the deformation change and that of temperature; deformation and elevation are positively correlated; the permafrost deformation is also affected by solar radiation that could form variable amplitude variation.

Spatio-temporal evolution of Allium L. in the Qinghai–Tibet-Plateau region: Immigration and in situ radiation

A plethora of studies investigating the origin and evolution of diverse mountain taxa has assumed a causal link between geological processes (orogenesis) and a biological response (diversification). Yet, a substantial delay (up to 30 Myr) between the start of orogenesis and diversification is often observed. Evolutionary biologists should therefore identify alternative drivers of diversification and maintenance of biodiversity in mountain systems. Using phylogenetic, biogeographic, and diversification rate analyses, we could identify two independent processes that most likely explain the diversity of the widespread genus Allium in the Qinghai–Tibet Plateau (QTP) region: (1) While the QTP-related taxa of the subgenus Melanocrommyum diversified in situ, (2) QTP-related taxa of other subgenera migrated into the QTP from multiple source areas. Furthermore, shifts in diversification rates within Allium could not be attributed spatially and temporally to the uplift history of the QTP region. Instead, global cooling and climate oscillations in the Quaternary were major contributors to increased speciation rates in three clades of Allium. Our study therefore adds to the growing evidence supporting the “mountain-geo-biodiversity hypothesis”, which highlights the role of climate oscillations for the diversification of mountain organisms.

Evolutionary radiations in the species-rich mountain genus Saxifraga L.

BackgroundA large number of taxa have undergone evolutionary radiations in mountainous areas, rendering alpine systems particularly suitable to study the extrinsic and intrinsic factors that have shaped diversification patterns in plants. The species-rich genus Saxifraga L. is widely distributed throughout the Northern Hemisphere, with high species numbers in the regions adjacent to the Qinghai-Tibet Plateau (QTP) in particular the Hengduan Mountains and the Himalayas. Using a dataset of 297 taxa (representing at least 60% of extant Saxifraga species), we explored the variation of infrageneric diversification rates. In addition, we used state-dependent speciation and extinction models to test the effects of geographic distribution in the Hengduan Mountains and the entire QTP region as well as of two morphological traits (cushion habit and specialized lime-secreting glands, so-called hydathodes) on the diversification of this genus.ResultsWe detected two to three rate shifts across the Saxifraga phylogeny and two of these shifts led to radiations within two large subclades of Saxifraga, sect. Ciliatae Haworth subsect. Hirculoideae Engl. & Irmsch. and sect. Porphyrion Tausch subsect. Kabschia Engl. GEOSSE analyses showed that presence in the Hengduan Mountains had a positive effect on diversification across Saxifraga. Influence of these mountains was strongest in Saxifraga sect. Ciliatae subsect. Hirculoideae given its pronounced distribution there, and thus the radiation in this group can be classified at least partially as geographic. In contrast, the evolution of the cushion life form and lime-secreting hydathodes had positive effects on diversification only in selected Saxifraga sections, including sect. Porphyrion subsect. Kabschia. We therefore argue that radiation in this group was likely adaptive.ConclusionsOur study underlines the complexity of processes and factors underpinning plant radiations: Even in closely related lineages occupying the same life zone, shifts in diversification are not necessarily governed by similar factors. In conclusion, alpine plant radiations result from a complex interaction among geographical settings and/or climatic modifications providing key opportunities for diversification as well as the evolution of key innovations.

Selective Preference Method of Highway Route Scheme in Permafrost Regions of Qinghai-Tibet Plateau Based on AHP and Fuzzy Comprehensive Evaluation

To solve the problem that traditional highway route selection method cannot fully consider the complex geographical environment in the permafrost region of Qinghai-Tibet Plateau, AHP (Analytic Hierarchy Process) and fuzzy comprehensive evaluation were introduced into the highway route comparison and selection in permafrost region. Influence degrees of various factors on different route schemes in permafrost regions of the Qinghai-Tibet Plateau were analyzed by the AHP. The annual average temperature, engineering reliability and engineering capacity were selected as the characteristic parameters and their weights were determined. Variation range of the various influencing factors in permafrost regions of the Qinghai-Tibet Plateau were analyzed by the fuzzy comprehensive evaluation, 5 evaluation grades of highway route scheme in permafrost regions were established, and the actual highway route schemes between Xiushui River and Yamarle River were compared and selected. The results show that the temperature and frozen soil diseases are the main factors affecting the highway route plan in the permafrost regions of the Tibetan plateau, outstanding route plan needs comprehensive consideration of stability of highway engineering and environmental protection.

Effect of simulative warming on growth and antioxidative characteristics of Kobresia pygmaea and K. tibetica in the permafrost region of Qinghai-Tibetan Plateau, China

In the present study, open top chambers (OTCs) were employed to simulate temperature increase at Fenghuoshan site, located on the hinterland of Qinghai-Tibetan Plateau. To explore the potential response mechanism of alpine plants under warmer temperature, the leaf morphological and antioxidative characteristics of two dominant species of alpine meadow (Kobresia pygmaea) and alpine swamp meadow (K. tibetica) were analyzed. The results showed that length and numbers of leaves in K. pygmaea increased by 40.0% and 72.7% by warming, respectively. Plant height and leaf length in K. tibetica increased by 11.9% and 19.3% by warming, respectively. Warming improved plant growth and aboveground biomass accumulation in both species. However, warming did not affect leaf membrane permeability (electrolyte leakage), active oxygen species (hydrogen peroxide and superoxide anion), activities of superoxide dismutase, peroxidase, ascorbate peroxidase and catalase, and malondialdehyde content in both species. Ascorbic acid and free proline contents in K. tibetica increased by 29.8% and 53.8%, respectively, but no change was found in K. pygmaea. In conclusion, K. pygmaea and K. tibetica could adapt under warmer temperature through keeping a steady antioxidative status.

Thermal Regime Analysis and Protective Measure Evaluation for Wide Embankment in Permafrost Regions of Qinghai-Tibet Plateau

This study analyzed the effects of a wide embankment on the thermal regime of permafrost and evaluated the feasibility of different measures to protect the permafrost underlying the wide embankment. Based on a specific embankment section of the Qinghai-Tibet highway and field observed data, a finite-element model was built and verified to conduct thermal analysis. Based on numerical analysis, the temperature fields and thawing depths of embankments with different widths were analyzed. The influences of different protective measures on the thermal stability of embankments were evaluated. The findings indicate that, after embankment construction, the annual ground temperature and maximum thawing depth increase with time. Thus, the embankment construction causes serious disturbance of the thermal stability of permafrost. An embankment with a larger width has a lower thermal stability. The results also show that raising the embankment height, setting a crushed stone layer, or setting an expanded polystyrene (EPS) layer can improve the thermal stability of an embankment. However, the improving effect of a single protective measure is not obvious for wide embankments with widths larger than 26 m. A combination of a crushed stone layer and an EPS layer provides the best protective effect on the thermal stability of a wide embankment. Thus, it is recommended as a protective measure for wide embankments of expressways in permafrost regions of the Qinghai-Tibet Plateau.

Transcriptomic analyses reveal biosynthetic genes related to rosmarinic acid in Dracocephalum tanguticum

Dracocephalum tanguticum Maxim, a Lamiaceae species endemic to the Qinghai-Tibetan Plateau and adjacent regions, is an important ornamental, medicinal and aromatic herb. In this study, a comprehensive transcriptome of 18 libraries from six organs namely, roots, stems, leaves, sepals, flowers and seeds of D. tanguticum were generated. More than 100 Gb of sequence data were obtained and assembled de novo into 187,447 transcripts, including 151,463 unigenes, among which the six organs shared 17.7% (26,841). In addition, all unigenes were assigned to 362 pathways, in which ‘biosynthesis of secondary metabolites’ is the second enriched pathway. Furthermore, rosmarinic acid (RA) is one of the multifunctional phenolic bioactive compounds produced in some Lamiaceae species. The six organs of D. tanguticum were confirmed to produce RA. A total of 22 predicted biosynthetic genes related to RA from the transcriptome were further isolated. Two of these genes were identified as candidates by evaluating the correlation coefficient between the RA contents and the expression of the predicted biosynthetic genes in the six organs. The new sequence information will improve the knowledge of D. tanguticum, as well as provide a reference tool for future studies of biosynthetic genes related to RA in this species.

Adaptive evolution of the rbcL gene in the genus Rheum (Polygonaceae)

ABSTRACTRapid putative radiations of Rheum might be caused by the recent uplifts of the Qinghai–Tibetan Plateau and the quaternary climate oscillations. To better understand the molecular adaptation associated with Rheum radiation, in this study, the adaptive evolution of the chloroplast rbcL gene was analysed using the Phylogenetic Analysis Program. The results showed that two amino acid residues (75F, 203I) were under positive selection. The spatial analysis indicated that the site (75F) was located in the β-sheet of the N-terminal loops involved in subunit interactions in the L8S8 molecule, and the site (203I) was in the α/β-barrel active centre located on the C-terminal domain of the large subunit of Rubisco. These results suggest that potential positive selection in rbcL might have played an important role in the adaption of Rheum species to the extreme environments in Qinghai–Tibetan Plateau regions, and different species lineages might have been subjected to different selective pressures.

青藏高原区域不同功能群植物氮磷生态化学计量学特征

青藏高原区域不同功能群植物氮磷生态化学计量学特征

Evolution and maintenance mechanisms of plant diversity in the Qinghai-Tibet Plateau and adjacent regions: retrospect and prospect

Evolution and maintenance mechanisms of plant diversity in the Qinghai-Tibet Plateau and adjacent regions: retrospect and prospect

青藏高原菊科特有属绢毛菊属核型的补充报道

菊科(Asteraceae)绢毛菊属( Soroseris )是青藏高原地区的特有类群，本文对采自青藏高原及其邻近地区的6种绢毛菊属植物的种子进行核型研究。利用常规压片法通过实验可以确定：绢毛菊属植物染色体基数都为8，除皱叶绢毛菊( S.hookeriana )为四倍体外其余5种都为二倍体，结果如下：金沙绢毛菊( S. gillii )：2n = 2x = 16 = 14 m + 2 sm。；绢毛菊( S. glomerata ) 2n = 2x = 16 = 14 m + 2 sm；空桶参( S. erysimoides ) 2n = 2x = 16 = 14 m + 2 sm；肉菊( S. umbrella )：2n = 2x = 16 = 16 m；羽裂绢毛菊(S. hirsuta)：2n = 2x = 16 = 14 m + 2 sm；皱叶绢毛菊( S.hookeriana )：2n = 4x = 32 = 32 m。核型分析结果表明，除绢毛菊( S. glomerata )和皱叶绢毛菊( S.hookeriana )为1A型外其余都为2A型。以上结果表明，绢毛菊属植染色体基数非常一致(x = 8)，该属植物物种分化的主要途径可能是二倍体水平的染色体结构变异及多倍化。 The genus Soroseris is a small genus of Asteraceae distributing primarily in the Qinghai-Tibet Pla-teau and adjacent regions. In this study, we report the chromosome numbers and karyotypes of 6 species originally assigned to Soroseris . By using the plant root tip cytology research method, the results showed that the chromosome base number is x = 8; the karyotype formulas respectively was: S. gillii with 2n = 2x = 16 = 14 m + 2 sm; S. glomerata with 2n = 2x = 16 = 14 m + 2 sm; S. erysimoides with 2n = 2x = 16 = 14 m + 2 sm; S. umbrella with 2n = 2x = 16 = 16 m; S. hirsute with 2n = 2x = 16 = 14 m + 2 sm; S.hookeriana with 2n = 4x = 32 = 32 m; Karyotypes of all the species ex-amined are relatively asymmetrical, and are classified as Stebbins’ types 1A and 2A. These findings suggest that all of the chromosome base number of Soroseris were x = 8, the variation of chromosome’s structure and polyploidization events played a major role in species diversification in this alpine genus.

A new moth-preying alpine pit viper species from Qinghai-Tibetan Plateau (Viperidae, Crotalinae)

The Sanjiangyuan region of Qinghai-Tibetan Plateau is recognized as a biodiversity hotspot of alpine mammals but a barren area in terms of amphibians and reptiles. Here, we describe a new pit viper species, Gloydius rubromaculatus sp. n. Shi, Li and Liu, 2017 that was discovered in this region, with a brief taxonomic revision of the genus Gloydius. The new species can be distinguished from the other congeneric species by the following characteristics: cardinal crossbands on the back, indistinct canthus rostralis, glossy dorsal scales, colubrid-like oval head shape, irregular small black spots on the head scales, black eyes and high altitude distribution (3300-4770 m above sea level). The mitochondrial phylogenetic reconstruction supported the validity of the new species and furthermore reaffirms that G. intermedius changdaoensis, G. halys cognatus, G. h. caraganus and G. h. stejnegeri should be elevated as full species. Gloydius rubromaculatus sp. n. was found to be insectivorous: preying on moths (Lepidoptera, Noctuidae, Sideridis sp.) in the wild. This unusual diet may be one of the key factors to the survival of this species in such a harsh alpine environment.

Identification of Triplophysa species from the Qinghai-Tibetan Plateau (QTP) and its adjacent regions through DNA barcodes

The genus Triplophysa is the largest and most difficult to identity morphologically fish group of superfamily Cobitoidea with 140 currently valid species, and is mainly distributed in the Qinghai-Tibetan Plateau (QTP) and adjacent regions. Most species within this genus possess highly similar morphological characteristics for adaption to the highland environment and are very difficult to be identified only based on morphology. The traditional species identification, mainly based on external morphological diagnostic characters, leads to inconsistent results in many cases. Herein, we provided a molecular method based on mitochondrial cytochrome c subunit I (COI) for the identification of Triplophysa fishes. Thirty-three Triplophysa species, 244 individuals, were used to determine whether barcoding was effective in discriminating species for this genus. The mean intraspecific and interspecific K2P distances ranged from 0 to 14.9% (mean, 2.9%) and 0 to 23.4% (mean, 9.7%), respectively. The tree-based analysis displayed most of species formed discrete clusters with strong bootstrap support values (>90%). The results showed that most of Triplophysa species could be identified by DNA barcode and indicated DNA barcode could be used as a molecular marker for these species.

In and out of the Qinghai‐Tibet Plateau: divergence time estimation and historical biogeography of the large arctic‐alpine genus Saxifraga L.

AbstractAimGeologically dynamic areas often harbour remarkable levels of biodiversity. Among other factors, mountain building is assumed to be a precondition for species radiation, and yet, the potential role of immigration as a source of biodiversity prior to radiation is often neglected. Here, we studied the biogeographical history of the large genus Saxifraga to unravel the role played by the Qinghai‐Tibet Plateau (QTP) for the diversification of this genus and to understand factors that have led to the establishment of high biodiversity in and around this region.LocationQTP and surrounding mountain ranges and worldwide distribution range of Saxifraga.MethodsUsing a total of 420 taxa (321 ingroup taxa) comprising more than 60% of extant Saxifraga species, we studied the evolutionary history of Saxifraga by performing phylogenetic analyses (maximum likelihood and Bayesian inference on nuclear ITS and plastid trnL–trnF, matK sequences), divergence time estimation (using uncorrelated log‐normal clock models and four fossil constraints in beast) and ancestral range estimation (using BioGeoBEARS).ResultsSaxifraga originated in North America around 74 (64–83) Ma, dispersed to South America and northern Asia during its early diversification and colonized Europe and the QTP region by the Late Eocene. The QTP region was colonized several times independently, followed in some lineages by rapid radiations, temporally coinciding with recent uplifts of the Hengduan Mountains at the southeastern fringe of the QTP. Subsequently, several lineages dispersed out of Tibet.Main conclusionsImmigration, recent rapid radiation and lineage persistence were all important processes for the establishment of a rich species stock of Saxifraga in the QTP region. Because floristic exchanges between the neighbouring areas and the QTP region were bi‐directional, the spatio‐temporal evolution of Saxifraga contrasts with the ‘out of QTP’ pattern, which has often been assumed for northern temperate plants.

Climate-driven increase of natural wetland methane emissions offset by human-induced wetland reduction in China over the past three decades.

Both anthropogenic activities and climate change can affect the biogeochemical processes of natural wetland methanogenesis. Quantifying possible impacts of changing climate and wetland area on wetland methane (CH4) emissions in China is important for improving our knowledge on CH4 budgets locally and globally. However, their respective and combined effects are uncertain. We incorporated changes in wetland area derived from remote sensing into a dynamic CH4 model to quantify the human and climate change induced contributions to natural wetland CH4 emissions in China over the past three decades. Here we found that human-induced wetland loss contributed 34.3% to the CH4 emissions reduction (0.92 TgCH4), and climate change contributed 20.4% to the CH4 emissions increase (0.31 TgCH4), suggesting that decreasing CH4 emissions due to human-induced wetland reductions has offset the increasing climate-driven CH4 emissions. With climate change only, temperature was a dominant controlling factor for wetland CH4 emissions in the northeast (high latitude) and Qinghai-Tibet Plateau (high altitude) regions, whereas precipitation had a considerable influence in relative arid north China. The inevitable uncertainties caused by the asynchronous for different regions or periods due to inter-annual or seasonal variations among remote sensing images should be considered in the wetland CH4 emissions estimation.