Ordos Plateau Research Articles

Future drought risks in the Yellow River Basin and suggestions for targeted response

Drought risk has posed severe challenges to social development and human security in the Yellow River Basin (YRB), which is vulnerable to water scarcity. When dealing with drought, the insufficient coordination among various departments caused by the uncertainty of the comprehensive drought risk under climate change could lead to water conflict. Therefore, in this study, the drought risk changes in the YRB under shared socioeconomic pathway (SSP) scenario 5–8.5 were assessed by integrating the temporally dynamic hazard with the static vulnerability and exposure. Then, suggestions for drought risk management were developed according to the spatial differentiation of the drought risk characteristics. The results show that the drought hazard may increase as the standardized precipitation evapotranspiration index (SPEI) decreases from the baseline (1985–2014; −0.04 ± 0.26) to the mid-term period (2041–2070; −0.09 ± 0.21), and may decrease as the SPEI increases (0.14/10 yr) significantly (p < 0.01) during the long-term period (2071–2100). As a result, the drought risk in the upstream, midstream, and downstream areas may change by 0.26 ± 0.56, −0.05 ± 0.49, and −0.86 ± 0.38 levels in the long term, respectively, compared with the baseline. To reduce the drought risk, it is suggested that agricultural technology be further developed in the southwestern upstream, central upstream, and northern midstream areas; the water management be strengthened in the Hetao Plain and Ordos Plateau; the scale of exposure be controlled in the provincial capitals, southeastern midstream, and downstream areas; and the drought disaster research and early warning system be improved in the areas between 105°E and 110°E. Detailed suggestions for drought risk response were developed for each specific region.

The Relationship and Influencing Factors between Endangered Plant Tetraena mongolica and Soil Microorganisms in West Ordos Desert Ecosystem, Northern China.

Soil microorganisms play crucial roles in improving nutrient cycling, maintaining soil fertility in desert ecosystems such as the West Ordos desert ecosystem in Northern China, which is home to a variety of endangered plants. However, the relationship between the plants-microorganisms-soil in the West Ordos desert ecosystem is still unclear. Tetraena mongolica, an endangered and dominant plant species in West Ordos, was selected as the research object in the present study. Results showed that (1) there were ten plant species in the Tetraena mongolica community, belonging to seven families and nine genera, respectively. The soil was strongly alkaline (pH = 9.22 ± 0.12) and the soil nutrients were relatively poor; (2) fungal diversity was more closely related to shrub diversity than bacterial and archaeal diversity; (3) among the fungal functional groups, endomycorrhizal led to a significant negative correlation between shrub diversity and fungal diversity, because endomycorrhizal had a significant positive effect on the dominance of T. mongolica, but had no significant effect on other shrubs; (4) plant diversity had a significant positive correlation with the soil inorganic carbon (SIC), total carbon (TC), available phosphorus (AVP) and available potassium (AVK). This study revealed the effects of soil properties and soil microorganisms on the community structure and the growth of T. mongolica and provided a theoretical basis for the conservation of T. mongolica and the maintenance of biodiversity in desert ecosystems.

RADseq-based population genomic analysis and environmental adaptation of rare and endangered recretohalophyte Reaumuria trigyna.

Genetic diversity reflects the survival potential, history, and population dynamics of an organism. It underlies the adaptive potential of populations and their response to environmental change. Reaumuria trigyna is an endemic species in the Eastern Alxa and West Ordos desert regions in China. The species has been considered a good candidate to explore the unique survival strategies of plants that inhabit this area. In this study, we performed population genomic analyses based on restriction-site associated DNA sequencing to understand the genetic diversity, population genetic structure, and differentiation of the species. Analyses of 92,719 high-quality single-nucleotide polymorphisms (SNPs) indicated that overall genetic diversity of R. trigyna was low (HO=0.249 and HE=0.208). No significant genetic differentiation was observed among the investigated populations. However, a subtle population genetic structure was detected. We suggest that this might be explained by adaptive diversification reinforced by the geographical isolation of populations. Overall, 3513 outlier SNPs were located in 243 gene-coding sequences in the R. trigyna transcriptome. Potential sites under diversifying selection occurred in genes (e.g., AP2/EREBP, E3 ubiquitin-protein ligase, FLS, and 4CL) related to phytohormone regulation and synthesis of secondary metabolites which have roles in adaptation of species. Our genetic analyses provide scientific criteria for evaluating the evolutionary capacity of R. trigyna and the discovery of unique adaptions. Our findings extend knowledge of refugia, environmental adaption, and evolution of germplasm resources that survive in the Ordos area.

A Bayesian Lasso Logistic Regression Model for Predicting the Probability of Regional Seismic Phase Observation UsingSnin the Middle East and East Asia as Examples

ABSTRACTHigh-frequency seismic wave blockage is often the result of strong attenuation, and the regional phase Sn is particularly prone to blockage in comparison with any of the other regional phases including Lg. As widespread blockage can lead to difficulty in the estimation of source parameters or path attenuation, accurate characterization of efficient regional wave propagation is necessary. We have applied two approaches to map Sn phase blockage: (1) the relatively standardized efficiency tomography and (2) a newly developed Bayesian logistic regression model that is able to predict the likelihood (probability) of phase blockage. As a byproduct of our Bayesian approach, we obtain measures of uncertainty for the probability of blockage. We applied both our methods on simulated efficiency data as well as real efficiency data obtained from earthquakes and stations from the middle east and eastern Asia. Our models successfully predict the probability of blockage zones with relatively high accuracy (&amp;gt;75%). In addition, we observe both low probability of Sn blockage and efficient Sn propagation in tectonically stable continental lithosphere, such as the Arabian plate, the Mediterranean Sea, northeastern Iran, the Ordos plateau, and the Sichuan basin. Regions with a high probability of Sn blockage or inefficient Sn propagation zones are in the tectonically active areas, such as the Tibetan and Iranian plateaus. Our probability of blockage model can also be used to image the regions where SnQ models are likely to be biased due to blocked data.

Late-Quaternary paleoearthquakes along the Liulengshan Fault on the northern Shanxi Rift system

The Liulengshan Fault (LLSF), which lies on the northeastern edge of the Ordos Plateau, is a controlling boundary fault in the northern part of the Shanxi Rift system (SRS). The displaced landforms show that the fault has undergone strong and frequent late-Quaternary seismic activities. In 1989 and 1991, two moderate–strong earthquake swarms (Ms=6.1 and Ms=5.8) successively occurred in the LLSF, and GPS velocity shows that the areas are extending at around 1–2 mm/a. However, there is no surface-rupturing earthquake reported on the LLSF in historical records. Thus, the study of paleoseismic history and rupture behavior of paleoearthquakes in late-Quaternary on the LLSF is of fundamental importance for understanding the future seismic risk of this fault. To solve these problems, we conducted paleoseismological trench excavations at two sites on the LLSF to establish its paleoearthquake history. On the basis of the field geological survey and interpretation of high-precision topographic data, we carried out large-scale fault mapping and excavated two trenches in Xujiabao and Luofengwa across the LLSF. Then, four events in the Xujiabao trench and three events in the Luofengwa trench are identified. Finally, combined with radiocarbon dating (C14), optically stimulated luminescence (OSL) and OxCal modeling, we constrained the ages of these events. Together with the previous results of paleoseismology inYin et al. (1997), we consider that different segments of the LLSF may rupture together at the same time. Therefore, a total of six paleoearthquake events since late-Quaternary have been finally confirmed at 44,151–30881a, 40,163-28045a, 28,233-19215a, 16,742-12915a, 12,788-8252a, and 8203–2300a BP. According to the empirical relationships between moment magnitude and rupture length, the best estimated magnitude is inferred to be in the range between Mw 6.9 and Mw 7.7. Considering the strong late-Quaternary activity and a long earthquake elapsed time, we propose that the LLSF might have a high seismic hazard potential in the near future.

О ДАТИРОВКЕ ЧЕРЕПИЦЫ, СОБРАННОЙ ПРИ АРХЕОЛОГИЧЕСКОМ ОБСЛЕДОВАНИИ «ДЛИННОЙ СТЕНЫ» ДОХАНЬСКОГО ВРЕМЕНИ НА СЕВЕРЕ ПРОВИНЦИИ ШЭНЬСИ

The article is devoted to the problem of dating a segment of a long (or “great”) wall built in the pre-Han time within the borders of the present Shaanxi province. Traditionally, the construction of this fortified line, going to the North across the Ordos plateau (including the north of Shaanxi), is attributed to the reign of the Qin Zhao-hsiang-wang (after 272 BC). However, the author previously formulated a hypothesis that the wall of Zhao-hsiang-wang ended no further than the Suide county, and the northern section of the wall across the Jingbian, Hengshan, Yulin and Shenmu counties was subsequently built by order of Qin Shi-huang, which, thus, in 214–210 BC did not hold the entire Ordos, but only a narrow strip of land on its eastern outskirts. The article deals with dating finds (tile fragments) obtained from the first archaeological survey of these long walls in Shaanxi (published in a two-volume report in 2015). The author concludes that all found fragments of tile-ends find analogies in the antiquites of the Qin and Han periods, including two tile-ends made by craftsmen resettled from the Qi kingdom conquered by Shi-huang in 221 BC. Technological imprints on tile gutters either have a wide dating within the 4th–2 nd centuries BC, or unambiguously date back to the Han time. This refutes the assertion of the authors of the 2015 report that the tile finds allegedly indicate the construction of walls in the pre-Qin period.

Tracking Changing Evidence of Water Erosion in Ordos Plateau, China Using the Google Earth Engine

Ordos Plateau is one of the primary sources of sediment in the Yellow River, and changes in regional soil erosion directly affect the ecological status of the lower reaches of the Yellow River. Many recent studies have been published using remote sensing (RS) and geographic information systems (GIS) to evaluate soil erosion. In this study, much satellite remote sensing data in the Google Earth Engine (GEE) can better track soil erosion protection, which is significant in guiding the ecological protection and restoration of the Ordos Plateau and the Yellow River basin. In this study, we used GEE to observe the changes in soil erosion in the Ordos area from 2013 to 2021. The Theil–Sen procedure and Mann–Kendall significance test methods were used to evaluate the trend of land erosion in the Ordos area from 2013 to 2021. Based on GEE, the RUSLE is applied to evaluate soil erosion and analyze the changing trend. As a result, (1) we found that the annual change of soil and water loss in the Ordos Plateau showed three stages: 2013–2015, 2016–2018, and 2018–2021. After 2018, soil loss decreased from 14 × 1017 Mg in 2018 to 4 × 1017 Mg in 2021, which indicates that the environmental restoration project started in 2018 has achieved encouraging results. (2) The results showed that 40.9% of the regional soil erosion trend showed a significant decline, and 45.7% of the regional soil erosion trend showed a slight decline. Only 13.3% of the regional soil erosion is on the rise. (3) The test results of different land use types show that 87.3% of soil erosion occurs in bare and cultivated land. Because the terrain of Ordos is relatively flat, 95.39–96.17% of soil erosion occurs in areas with a slope of 0 to 5. (4) The reliability of the RUSLE model based on the GEE platform is proved by regression model verification of observation data and model prediction results. (5) GEE’s cloud-based features can provide data and scripts to users in developing countries which lack sufficient observation data or the necessary computing resources to develop these data. The results show that GEE has robust analysis and processing ability, can analyze a large amount of data, and can provide efficient digital products for soil erosion research.

Comparative chloroplast genomics provides insights into the genealogical relationships of endangered Tetraena mongolica and the chloroplast genome evolution of related Zygophyllaceae species.

A comprehensive understanding of genetic background for rare species will provide an important theoretical basis for the future species management, monitoring and conservation. Tetraena mongolica is restrictedly distributed in the western Ordos plateau of China and has been listed as a national protected plant. We generated 13 chloroplast (cp) genomes of T. mongolica (size range of 106,062-106,230bp) and conducted a series of comparative analyses of six Zygophyllaceae cp genomes. T. mongolica cp genome exhibited a quadripartite structure with drastically reduced inverted repeats (IRs, 4,315bp) and undergone the loss of a suit of ndh genes and a copy of rRNAs. Furthermore, all the T. mongolica populations were divided into two genetic groups based on complete cp phylogenomics. In addition, notably variable genome size, gene order and structural changes had been observed among the six Zygophyllaceae cp genomes. Overall, our findings provide insights into the cp genome evolution mode and intraspecific relationships of T. mongolica, and provide a molecular basis for scientific conservation of this endangered plant.

Identifying prioritized afforestation types in ecologically vulnerable zones of Northern China considering reducing water consumption and increasing carbon sequestration

Afforestation is one of the most important measures to control soil erosion and desertification in Northern China. Meanwhile, considering that afforestation in Northern China needs to increase carbon sequestration (CS) and reduce water consumption (WC), it is essential to select prioritized afforestation types in suitable regions. In this work, we identified ecologically vulnerable zones based on soil water and wind erosion assessment, evaluated tree and shrub afforestation suitability, and thus recognized potential afforestation regions. Further, we set four scenarios for different goals, and identified the prioritized afforestation types in each scenario. The results showed that potential afforestation regions are mainly distributed in the Loess Plateau, Western Liao River, Ordos Plateau, and Tarim Basin. Scenario 1 (aiming to minimize WC) is dominated by shrub afforestation and grassland restoration. This scenario will reduce WC by 3.1%-6.4% compared to other scenarios, but it will also decrease CS by 9.4%-56.1% and soil conservation (SC) by 7.7%-13.0%. Scenario 2 (aiming to maximize CS) is dominated by tree and shrub afforestation. This scenario will fix 41.8%-56.1% more carbon, and consume 3.0%-6.4% more water than the other scenarios. Meanwhile, this scenario can maximize SC, but also may reduce sand fixation (SF). Scenario 3 (aiming to maximize CS in humid region and minimize WC in arid region) and Scenario 4 (aiming to enhance both SC and SF) are dominated by shrub afforestation, tree afforestation and grassland restoration. The two scenarios can balance CS and WC, and have advantages in improving both SC and SF. In addition, Scenario 4 performs better than Scenario 3. In the future, it is better to implement tree afforestation mainly in sub-humid area, and conduct shrub afforestation mainly in arid and semi-arid regions. This study can provide guidance for the planning and management of afforestation projects in Northern China and other water scarcity areas.

Seismic imaging of the crust and uppermost mantle structure in the Qinling orogenic belt and its surroundings: Geodynamic implications

The Qinling orogenic belt and surrounding areas are a junction zone in Central China that connects the North China craton, Yangtze craton and northeastern Tibetan plateau. This area is in a key position within the more general framework where there is eastward extrusion of the Tibetan plateau and westward subduction of the Pacific plate. There is an ongoing scientific debate on how these two main processes are driving the geodynamic evolution of the Qinling orogenic belt and surrounding areas. Specific mechanisms have been proposed, such as lower crustal flow, crustal shortening and big mantle wedge tectonics. Knowledge of the seismic velocity structure helps us understand how these two driving forces affect the tectonic blocks of the study area, as well as test how well the proposed mechanisms to fit the regional velocity structure. For this purpose, a high-resolution P-wave velocity model of the crust and uppermost mantle was obtained by inverting arrival times from local earthquakes that occurred in the Qinling and surrounding region. Our three-dimensional (3D) model suggests that crustal channel flow cannot exist in the whole Qinling orogenic belt, and the localized low-velocity zone generated by the horizontal compressive stress caused by the collision of the Indian and Eurasian plates, is a possible explanation for the growth of the northeastern Tibetan plateau. The contrast in seismic velocities found under the east-Qinling and the west-Qinling orogenic belts implies a different response of these two terranes to the eastward extrusion of the Tibetan plateau. Our velocity model points to relatively stable structural features in the east-Qinling and the Weihe graben, while a low-velocity anomaly in the uppermost mantle of the southernmost Ordos plateau suggests that the lithosphere of the southern Ordos plateau is undergoing destruction.

Temporal variations in root-associated fungal communities of Potaninia mongolica, an endangered relict shrub species in the semi-arid desert of Northwest China.

The semi-arid region of the Western Ordos plateau in Inner Mongolia, China, is home to a critically endangered shrub species, Potaninia mongolica, which originates from ancient Mediterranean regions. Root-associated microbiomes play important roles in plant nutrition, productivity, and resistance to environmental stress particularly in the harsh desert environment; however, the succession of root-associated fungi during the growth stages of P. mongolica is still unclear. This study aimed to examine root-associated fungal communities of this relict plant species across three seasons (spring, summer and autumn) using root sampling and Illumina Miseq sequencing of internal transcribed spacer 2 (ITS 2) region to target fungi. The analysis detected 698 fungal OTUs in association with P. mongolica roots, and the fungal richness increased significantly from spring to summer and autumn. Eurotiales, Hypocreales, Chaetothyriales, Pleosporales, Helotiales, Agaricales and Xylariales were the dominant fungal orders. Fungal community composition was significantly different between the three seasons, and the fungal taxa at various levels showed biased distribution and preferences. Stochastic processes predominantly drove community assembly of fungi in spring while deterministic processes acted more in the later seasons. The findings revealed the temporal dynamics of root-associated fungal communities of P. mongolica, which may enhance our understanding of biodiversity and changes along with seasonal alteration in the desert, and predict the response of fungal community to future global changes.

Distribution of Glycerol Dialkyl Glycerol Tetraethers (GDGTs) in Carbonate-Type and Sulfate-Type Lacustrine Sediments: Insight into the Influence of Ionic Composition on GDGTs

The distribution of glycerol dialkyl glycerol tetraethers (GDGTs) in carbonate-type and sulfate-type saline lacustrine sediments from the Ordos Plateau in China is investigated to explore the influence of ionic composition on GDGTs. In general, they are relatively small (1.2–6.0 km2 surface area) and shallow ponds (0.05–0.2 m water depth) and even seasonally dry lakes. The results reveal that the concentration of GDGTs has a good positive correlation with the (nCO32− + nHCO3−)/total ions, and the concentration of GDGTs in carbonate-type lake sediments is significantly higher than that in sulfate-type lake sediments. Most GDGT-based indices show no significant differences, and the distributions of GDGTs are similar in the two types of saline lake sediments. The lack of a positive correlation between the content of clay minerals and the concentration of GDGTs may imply that the ability of clay minerals to carry terrigenous organic matter is very limited in arid climates. The branched GDGTS (brGDGTs) in the two saline lake sediments may mainly come from in situ biological production and have low terrestrial inputs. The different weathering level of feldspar minerals in the two types of saline lakes results in the difference in organic matter content, which ultimately affects the concentration of GDGTs.

Distribution characteristics, source identification, and risk assessment of heavy metals in surface sediments of the salt lakes in the Ordos Plateau, China.

Salt lakes considerably affect the regional climate, environment, and ecology of semiarid regions characterized by low rainfall and high evaporation. However, under the stresses of global change and human disturbance, anthropogenic pollution is the primary factor threatening the lake's ecological environment. Surface sediment samples collected from four salt lakes in the Ordos Plateau were used to investigate the salinity, concentration, pollution status, potential sources of heavy metals, and influencing factors. The surface sediments of Beida Pond and Gouchi Pond were weakly alkaline (pH < 9) due to the presence of Na2SO4, whereas those of Chaigannaoer and Hongjiannao were strongly alkaline (pH > 9) due to the presence of Na2CO3. The concentration range of Cr, Ni, Cu, Zn, As, Cd, and Pb in the sediment samples collected from the salt lakes in the Ordos Plateau followed the order of Cr > Zn > Ni > Pb > Cu > As > Cd. The Cr concentration values were higher in Chagannaoer and Hongjiannao; however, the Ni, Cu, and Zn values were higher in Beida Pond and Gouchi Pond. The geoaccumulation index (Igeo) and enrichment factor (EF) consistently indicated that Cr posed the greatest potential ecological risk and that Ni, Cu, and Zn pollution was more severe in Beida Pond and Gouchi Pond than in Chagannaoer or Hongjiannao. However, the ecological risk index and potential ecological risk value indicated that these heavy metals posed low risks to the environment. The risk assessment code (RAC) revealed that Pb and Cr exhibited no mobility and had low potential bioavailability risk. Meanwhile, Zn, Ni, and As were categorized as medium risk. Cu had the highest mobility and was categorized as high risk. Principal component analysis for the four salt lakes revealed that the source of Ni, Cu, Zn, and Cd might be associated with water-soluble elements associated with aqueous migration, while the source of Cr, Pb, and As might be the lithospheric minerals carried by dust storms. Pearson's correlation analysis indicated that clay minerals were the primary adsorbers of Ni, Cu, Zn, and Cd. Moreover, pH was identified as the main environmental factor controlling the distribution of heavy metals in the salt lakes.

Enrichment mechanisms for the co-occurrence of arsenic-fluoride-iodine in the groundwater in different sedimentary environments of the Hetao Basin, China

Abnormal levels of co-occurring arsenic (As), fluoride (F−) and iodine (I) in groundwater at the Hetao Basin are geochemically unique. The abnormal distribution of As, F− and I is obviously related to the sedimentary environment. It is necessary to study the enrichment mechanisms for the co-occurrence of As, F− and I in groundwater under the influence of the sedimentary environment in Hetao Basin. In this study, 499 groundwater samples were collected. Sedimentary environments, hydrogeochemical process, isotopes were analyzed to elucidate their enrichment mechanisms. The environment of groundwater is weakly alkaline. The hydrochemical types of groundwater are mainly Na–Cl–HCO3. The distribution of isotope δ18O demonstrates that irrigation from the Yellow River is the main recharge source. The main drainage channel is the discharge area in the Hetao basin. Based on the clay-sand ratio (R), the number of clay layers (N) and terrain slope (S), Hetao Basin was divided into four sedimentary environmental zones. The distribution of As (0–916.70 μg/L), F− (0.05–8.60 mg/L) and I (0.01–3.00 mg/L) was featured by a clear zonation of the sedimentary environment. The high As and high I groundwater were mainly distributed in the paleochannel zone of the Yellow River, with exceedance rates of 80.28% and 52.58%, and the median values of 73.91 μg/L and 0.11 mg/L, respectively. In the reducing environment, the release of As initially adsorbed on iron hydrogen and iron oxide, the reductive of iron hydroxide itself, rock weathering and evaporation are the key factors affecting the enrichment of As in groundwater. In this area, large amounts of aquatic organisms and plankton deposited in the sediment and channel filling deposits abundant with organic matter is the premise of high-I groundwater. The reduction of iodate and nitrate directly leads to the high concentration of I in groundwater. The high F− groundwater was mainly distributed in the piedmont alluvial-pluvial fan and the north margin of Ordos Plateau, with exceedance rates of 58.62% and 43.30%, and the median values of 1.10 mg/L and 0.86 mg/L, respectively. High F− groundwater in the two zones is affected by the abundant biotite and hornblende in Langshan Mountain and Ordos Plateau. Under evaporation, the precipitation rate of CaF2 and pH plays key roles in the enrichment of F− in groundwater. In the Hetao Basin, sedimentary environment is the main controlling factor for the co-mobilization of As, F− and I in groundwater.

Magnetostratigraphy of the fluvio-lacustrine sequence of core DY-1 in the Datong Basin and its implications for the evolution of the Shanxi Rift System in northern China

The Shanxi Rift System is an intracontinental rift system located between the North China Plain and Ordos Plateau, which was infilled with thousands of meters of Cenozoic fluvio-lacustrine deposits. A comprehensive chronological framework will help better understand the formation and evolutionary process of the rift system. Here, we present a new magnetochronology for the Datong Basin sedimentary sequence in the northern Shanxi Rift System based on high-resolution magnetostratigraphic investigations of the DY-1 core. Correlation of the recognized magnetic polarity sequence of the DY-1 core with the Astronomically Tuned Neogene Time Scale shows that the fluvio-lacustrine sequence in the Datong Basin spans from Chron C3Bn to Chron C1n. The age of the Datong Basin sedimentary sequence can thus be paleomagnetically constrained to an interval from the late Late Miocene to Middle Pleistocene. The basal age of the sediments is ca. 7.0 Ma, which indicates that the initial extension of the northern segment of the Shanxi Rift System was no later than 7.0 Ma. The Datong Basin in the northern Shanxi Rift System has experienced a three-stage evolution: During the initial stage (7.0–4.2 Ma), fluvial environments are dominant. Then during 4.2–1.8 Ma, lacustrine environments are developed due to dip-slip fault activities, as part of the Nihewan paleolake. After 1.8 Ma, the lake gradually shrank. The northeastward progressive growth and expansion of the Tibetan Plateau may have driven the evolution of the Shanxi Rift System.

Remote Sensing of Ecosystem Water Use Efficiency in Different Ecozones of the North China Plain

Water use efficiency (WUE), as an environmental factor of metabolism in different ecosystem functional areas, is a key indicator of the ecosystem carbon-water cycle. WUE is defined as the ratio of carbon absorbed by ecosystems to water evaporated. Exploring the spatiotemporal variation in carbon and water cycles in different ecological zones of the North China Plain and their driving factors is important for the ecological management and sustainable development of the different ecological zones in the North China Plain. Based on remote sensing data products, this paper studies the spatiotemporal variations of WUE and their driving factors in different ecological functional areas of the North China Plain from 2001 to 2017. This study found that: (1) The spatial distribution of WUE and gross primary production (GPP) in the North China Plain is similar, with the multiyear average of WUE at 0.74 g C m−2 y−1. The variation trend of WUE is mainly affected by the variation trend of GPP (44.38% of the area of the North China Plain). (2) The change trend of WUE mainly showed a mild decrease and a mild increase, accounting for 73.22% of the area of the North China Plain; the area with medium-low fluctuation of WUE accounted for the largest proportion, accounting for 59.90% of the area of the North China Plain. In addition, the multiyear average values of WUE in the ecological functional area are Qin Ling Mountains deciduous forests &gt; Central China loess plateau mixed forests &gt; Mongolian-Manchurian grassland &gt; Ordos Plateau steppe &gt; Changjiang Plain evergreen forests &gt; Huang He Plain mixed forests &gt; Bohai Sea saline meadow, in the order from high to low. (3) The influence of precipitation on WUE was higher than that of temperature. The area of WUE that increased with the increase of precipitation accounted for 23.74% of the area of the North China Plain and was mainly distributed in the Qin Ling Mountains deciduous forests, Changjiang Plain evergreen forests, and Huang He Plain mixed forests’ ecological functional areas. The results of the study can provide a reference and theoretical basis for the conservation and management of carbon and water cycles in the functional areas of North China’s ecosystems.

An Upper Paleolithic Perforated Red Deer Canine With Geometric Engravings From QG10, Ningxia, Northwest China

Personal ornaments are key archaeological remains to investigate prehistoric symbolic systems, and, whenever hard animal remains were used for their manufacture, explore topics on the status attributed to faunal resources by past human groups. Since the onset of the Upper Paleolithic, animal tooth pendants have been widely used in Eurasia as personal adornments or grave goods. However, only two Late Paleolithic Chinese sites have yielded such adornment types until today, i.e., Zhoukoudian Upper Cave, near Beijing, and Xiaogushan, in the Liaoning Province. Here, we present results from the multidisciplinary analysis of a perforated animal tooth from QG10, a multi-stratified archaeological site located on the Ordos Plateau between the arid and sub-arid belts of Northwest China. Although only partially preserved, zooarchaeological analysis indicates the tooth is a right upper canine of a female red deer (Cervus elaphus). Scraping marks on the labial aspect suggest the tooth was extracted from the animal maxillary shortly after its death. Technological analysis of the perforation confirms it was made by rotation with the help of a lithic point hafted onto a drill. The root and occlusal aspect of the tooth were further modified with five sets of notches and incisions, including four incisions making a hashtag pattern on the occlusal aspect. Technological and morphometric analyses indicate these sets were made by two, perhaps three, individual, i.e., one left-handed and one, perhaps two right-handed, with different tools and techniques. Use wear analysis suggests that the adornment was affixed to the body with the tooth crown facing upward. Finally, chemical characterization of red and black residues still adhering to the root indicates that hematite and charcoal may have been used in the production of an adhesive that would have helped stabilize the personal ornament on the body. Collectively, our results and interpretations shed a new light on the complexity of Late Glacial symbolic system carried by populations living in Northern China. We argue this perforated red deer tooth was introduced in the site following a number of social exchanges over long distance and a long period of time rather than producedin situ.

鄂尔多斯台地盐沼滩涂湿地土壤细菌群落结构及特征

PDF HTML阅读 XML下载 导出引用 引用提醒 鄂尔多斯台地盐沼滩涂湿地土壤细菌群落结构及特征 DOI: 10.5846/stxb202012313339 作者: 作者单位: 作者简介: 通讯作者: 中图分类号: 基金项目: 国家自然科学基金项目（41761102） Characteristics and distribution of soil bacterial of salt marsh tidal wetland in Ordos Platform Author: Affiliation: Fund Project: 摘要 | 图/表 | 访问统计 | 参考文献 | 相似文献 | 引证文献 | 资源附件 | 文章评论 摘要:依据植被分类法将鄂尔多斯高原盐沼滩涂湿地划分为肉质耐盐草甸（B）、苔草草甸（C）、禾草草甸（D）和杂类草草甸（E）等4个植被亚型，并以盐沼裸地（A）为对照样地，共计5种盐沼滩涂湿地景观类型。运用高通量测序技术分别研究其土壤细菌群落结构特征、分布情况，以及土壤盐分与土壤细菌之间的关系。结果表明：（1）5种盐沼滩涂湿地的土壤细菌样品共12213条OTUs，属于45个门，122个纲，365个目，663个科，1375个属，2882个种。（2）变形菌门（26.19%）是盐沼滩涂湿地平均相对丰度最高的门，其次为放线菌门（17.15%），绿弯菌门（12.62%），芽单胞菌门（Gemmatimonadetes，11.23%），拟杆菌门（Bacteroidetes，9.38%），酸杆菌门（Acidobacteria，8.83%）厚壁菌门（Firmicutes，2.96%）；芽单胞菌纲中的未定细菌（norank_c_Gemmatimonadetes）是丰度最高的属，平均丰度为5.75%。（3）鄂尔多斯盐沼滩涂湿地自西南向东北，空间位置相近的土壤细菌群落结构具有更大的相似性，随着土壤盐分变化，变形菌门相对丰度存在先增大后减小的趋势，与异常球菌-栖热门菌的变化趋势相反，绿弯菌门、酸杆菌门相对丰度大致呈不断增大的趋势，拟杆菌门和厚壁菌门大体呈逐渐减少的趋势，芽单胞菌门和（Rokubacteria）的变化趋势上下波动，不稳定（4）不同盐沼滩涂湿地土壤细菌群落丰度与多样性的结果均表现为：苔草草甸>杂类草草甸>禾草草甸>肉质耐盐草甸>盐沼裸地。（5）在土壤盐分指标中，与鄂尔多斯盐沼滩涂湿地细菌群落相关性依次为TS> CO32-> Na+> Cl-> pH > SO42- >K+> Mg2+> Ca2+> HCO3-。此研究结果不仅可为揭示鄂尔多斯高原盐沼滩涂湿地土壤细菌区系组成及其对应的环境特征的变化规律提供理论依据，而且进一步探讨了土壤盐分与土壤微生物之间的关系，为高原盐沼地区的土壤修复及生境演替提供了参考。 Abstract:According to the vegetation classification method, the salt marsh tidal wetland in Ordos Plateau was divided into 4 vegetation subtypes, such as succulent salt-tolerant meadow (B), carex meadow (C), grass meadow (D) and forbs meadow (E). meanwhile, salt marsh bare land (A) was taken as the control plot, there are five landscape types of salt marsh tidal wetland designed. The structure characteristics and distribution of soil bacterial community and the relationship between soil salinity and soil bacteria were studied by high-throughput sequencing technique. The results showed that:(1) There were 12213 OTUs in the soil bacteria samples of 5 kinds of salt marsh tidal wetland, which belonged to 2882 species, 1375 genera, 663 families, 365 orders, 122 classes and 45 phyla. (2) Proteobacteria (26.19%) was the highest average relative abundance of salt marsh tidal wetland, followed by Actinobacteria (17.15%), Chloroflexi (12.62%), Gemmatimonadetes (11.23%), Bacteroidetes (9.38%), Acidobacteria (8.83%) and Firmicutes (2.96%); the undetermined bacterium (norank_c_Gemmatimonadetes) in Gemmatimonadetes was the most abundant genus with an average abundance of 5.75%. (3) The community structure of soil bacteria with close spatial positions had a greater similarity from southwest to northeast in Ordos salt marsh tidal wetland. With the change of salt content in soil, the relative abundance of Proteobacteria increased at first and then decreased, which was contrary to the change trend of Deinococcus-Thermus; the relative abundance of Chloroflexi and Acidobacteria showed an increasing trend. Bacteroidetes and Firmicutes generally showed a decreasing trend, and Gemmatimonadetes and Rokubacteria showed a fluctuating and unstable change trend. (4) The abundance and diversity of soil bacterial community in different salt marsh tidal wetlands were as follows:carex meadow > forbs meadow > grass meadow > succulent salt-tolerant meadow > salt marsh bare land. (5) The correlation between soil salinity and bacterial community in Ordos salt marsh tidal wetland from high to low was as follows:TS > CO32-> Na + > Cl-> pH > SO42-> K + > Mg2 + > Ca2+> HCO3-. The results of this study could not only provide theoretical basis for revealing the composition of soil bacterial flora in salt marsh tidal wetland of Ordos Plateau and the change law of its corresponding environmental characteristics, but also further explored the relationship between soil salinity and soil microorganisms, so as to provide reference for soil remediation and habitat succession in salt marsh areas of Ordos Plateau. 参考文献 相似文献 引证文献

黄河流域濒危物种保护热点区与保护空缺识别

黄河流域具有重要的生物多样性保护意义，通过研究珍稀濒危物种分布热点区可为生物多样性保护提供依据。选取70种濒危维管植物和陆生脊椎动物，综合多来源的分布数据，运用物种分布模型Maxent模拟物种分布区，结合自然地理区划，计算保护价值，进行热点区分析，并结合国家级自然保护区和国家公园体制试点区的分布情况进行空缺分析。研究结果显示，黄河流域濒危物种分布主要呈现出南高北低、集中于山地的特征，热点区包括秦岭区域、太行山区域、子午岭-六盘山区域、陇中高原至松潘高原、祁连山、贺兰山和沿黄湿地等。在区分自然地理区后，现有的国家级自然保护区和国家公园体制试点区覆盖了热点区面积的13.89%，保护空缺主要出现于子午岭南部、六盘山南部、松潘高原南部和拉脊山等。建议在推进黄河流域生态保护和高质量发展中将濒危物种热点区考虑在内，对黄河流域自然保护地体系进行优化，并针对黄河流域的三个自然地理分区提出了相应的保护建议。此外，研究发现，在进行热点区分析时，考虑自然地理区域划分，并综合多类群叠加和单一生物类群的分析结果进行统筹考虑，可能会更好满足生物多样性就地保护需求。;The Yellow River Basin has important biodiversity protection significance. Research on the distribution hotspots of rare and endangered species can provide a basis for biodiversity protection and establishing protected area system. In this study, 70 endangered species were selected, including 26 vascular plants and 44 terrestrial vertebrates. Distribution data from multiple sources of these species were integrated to provide distribution point samples for modeling. The species distribution model Maxent was used to simulate distribution areas. All the Maxent simulation results were superimposed according to different taxa and physical geographical regions, and we calculated the biodiversity conservation value for analyzing hot spots. the conservation gaps were analyzed by integrating the distribution layer of national nature reserves and national parks (pilot area). Results show that the distribution of endangered species in the Yellow River Basin is mainly high in the south, and is concentrated in the mountain areas. The hot spots include Qinling Mountains, Taihang Mountains, Ziwuling-Liupan Mountains, Longzhong Plateau to Songpan Plateau, Qilian Mountains, Helan Mountains, and wetlands along the Yellow River. After distinguishing the geographical regions, the existing national nature reserves and national parks (pilot area) cover 13.89% of the hot spots' area, and the protection gaps are mainly found in the southern Ziwuling Mountains, the southern Liupanshan Mountains, the southern Songpan Plateau and the Laki Mountains. It is suggested that the threatened species hotspots should be taken into account in ecological conservation and high-quality development planning of the Yellow River Basin, and the natural protected area system of the Yellow River Basin should be optimized. For three different physical geographical regions in Yellow River Basin, specific suggestions are put forward:in Qinghai-Tibet Alpine Region, the protected areas should be optimized and biodiversity survey should be strengthened; in Northwest Arid and Semi-arid Region, lakes in Ordos Plateau are worthy of the enhanced protection; in Eastern Monsoon Region, the leopard, great bustard and Baer's pochard should be considered as key species and put more efforts on their habitat protection. In addition, this study also shows that, when analyzing biodiversity hotspots, considering the division of physically geographic regions and combining the hot spot analysis results of multiple taxa and single taxa for overall consideration may be better for meeting the needs of biodiversity in-situ conservation.

Quantitative Estimates of Holocene Precipitation from Aeolian Sand-Palaeosol Sequences Across the Ordos Plateau, Northern China, Based on Surface Soil Geochemistry

Quantitative Estimates of Holocene Precipitation from Aeolian Sand-Palaeosol Sequences Across the Ordos Plateau, Northern China, Based on Surface Soil Geochemistry