Eurasian Steppe Research Articles

The draft genome of Spiraea crenata L. (Rosaceae) – the first complete genome in tribe Spiraeeae

Spiraea crenata L. is a deciduous shrub distributed across the Eurasian steppe zone. The species is of cultural and horticultural importance and occurs in scattered populations throughout its westernmost range. Currently, there is no genomic information on the tribe of Spiraeeae. Therefore we sequenced and assembled the whole genome of S. crenata using second- and third-generation sequencing and a hybrid assembly approach to expand genomic resources for conservation and support research on this horticulturally important lineage. In addition to the organellar genomes (the plastome and the mitochondrion), we present the first draft genome of the species with an estimated size of 220 Mbp, an N50 value of 7.7 Mbp, and a BUSCO score of 96.0%. Being the first complete genome in tribe Spiraeeae, this may not only be the first step in the genomic study of a rare plant but also a contribution to genomic resources supporting the study of biodiversity and evolutionary history of Rosaceae.

The Tang legacy on the Silk Road during the Uighur era: urbanisation in the eastern Tianshan region during the ninth to thirteenth centuries

AbstractTang expansion in the early seventh century brought about a series of changes to the eastern Tianshan region, including the incorporation of the region into the imperial postal relay and defence system. Important structures, including cities for the soldiers and other immigrants from Tang territory, along with fortresses and relay posts, were established along the major routes in the region, especially on the northern slopes of the Tianshan range. However, the era after the decline of the Tang is not as well known, due to a lack of contemporary sources. This article, based on a comprehensive analysis of documentary and unearthed materials, discusses a previously unacknowledged process of urbanisation in the region during the Uighur era. Uighur immigrants, originally nomads on the Mongolian steppe, occupied not only the cities, but also the garrisons and other infrastructure established by the Tang. As a result, urban settlements were established at sites that had previously served military purposes. Clusters of new cities emerged in the region, especially on the northern slopes of the Tianshan, which had long been part of the nomadic cultural zone. The sedentary and mercantile culture of the Uighurs played an important role in this process, serving as an impetus for economic prosperity along the eastern section of the Silk Road between the Tang and Mongol–Yuan eras.

The greenhouse gas emissions from meat sheep production contribute double of household consumption in a Eurasian meadow steppe

With the rapid development of the economy, household activities have emerged as an important source of greenhouse gas (GHG) emissions, making them a crucial focal point for research in the pursuit of sustainable development and carbon emission reduction. Hulunber, as a typical steppe region in eastern Eurasia, is representative of studying the GHG emissions from household ranches, which are the basic production units in this region. In this paper, based on survey data of 2018 and 2019, we quantified and assessed GHG emissions from household ranches by combining life cycle assessment (LCA) and structural equation modeling (SEM) approaches, with LCA to define household ranches system boundary and SEM to determine the key driving factors of emissions. The results showed that GHG emissions of meat sheep live weight was 23.54 kg CO2-eq/kg. The major contributor to household GHG emissions was enteric methane (55.23 %), followed by coal use (20.80 %) and manure management systems (9.16 %), and other contributing factors (14.81 %). The SEM results indicated that the GHG emissions from household ranches were derived primarily by economic level, while the economic level was significantly affected by income. This study also found a significant positive and linear correlation between household GHG emissions and the number of meat sheep (R2 = 0.89, P < 0.001). The GHG emissions from meat sheep production (67.52 %) were double times greater than household livelihood consumption (32.48 %). These findings emphasized the importance of reducing emissions from meat sheep production and adjusting the energy mix of household livelihood, contributing to the establishment of a low-carbon household livelihood operation.

Spatial Variation in Responses of Plant Spring Phenology to Climate Warming in Grasslands of Inner Mongolia: Drivers and Application.

Plant spring phenology in grasslands distributed in the Northern Hemisphere is highly responsive to climate warming. The growth of plants is intricately influenced by not only air temperature but also precipitation and soil factors, both of which exhibit spatial variation. Given the critical impact of the plant growth season on the livelihood of husbandry communities in grasslands, it becomes imperative to comprehend regional-scale spatial variation in the response of plant spring phenology to climate warming and the effects of precipitation and soil factors on such variation. This understanding is beneficial for region-specific phenology predictions in husbandry communities. In this study, we analyzed the spatial pattern of the correlation coefficient between the start date of the plant growth season (SOS) and the average winter-spring air temperature (WST) of Inner Mongolia grassland from 2003 to 2019. Subsequently, we analyzed the importance of 13 precipitation and soil factors for the correlation between SOS and average WST using a random forest model and analyzed the interactive effect of the important factors on the SOS using linear mixing models (LMMs). Based on these, we established SOS models using data from pastoral areas within different types of grassland. The percentage of areas with a negative correlation between SOS and average WST in meadow and typical grasslands was higher than that in desert grasslands. Results from the random forest model highlighted the significance of snow cover days (SCD), soil organic carbon (SOC), and soil nitrogen content (SNC) as influential factors affecting the correlation between SOS and average WST. Meadow grasslands exhibited significantly higher levels of SCD, SOC, and SNC compared to typical and desert grasslands. The LMMs indicated that the interaction of grassland type and the average WST and SCD can effectively explain the variation in SOS. The multiple linear models that incorporated both average WST and SCD proved to be better than models utilizing WST or SCD alone in predicting SOS. These findings indicate that the spatial patterns of precipitation and soil factors are closely associated with the spatial variation in the response of SOS to climate warming in Inner Mongolia grassland. Moreover, the average WST and SCD, when considered jointly, can be used to predict plant spring phenology in husbandry communities.

Spatiotemporal patterns and driving factors of gross primary productivity over the Mongolian Plateau steppe in the past 20 years

The Eurasian steppe is the largest temperate grassland in the world. The grassland of the Mongolian Plateau (MP) represents an important part of the Eurasian steppe with high climatic sensitivity. Gross primary productivity (GPP) is a key indicator of the grassland's production, status and dynamic on the MP. In this study, we calibrated and evaluated the grassland-specific light use efficiency model (GRASS-LUE) against the observed GPP collected from nine eddy covariance flux sites on the MP, and compared the performance with other four GPP products (MOD17, VPM, GLASS and GOSIF). GRASS-LUE with higher R2 (0.91) and lower root mean square error (RMSE = 0.99 gC m−2 day−1) showed a better performance compared to the four GPP products in terms of model accuracy and dynamic consistency, especially in typical and desert steppe. The parameters of the GRASS-LUE are more suitable for water-limited grassland could be the reason for its outstanding performance in typical and desert steppe. Mean grassland GPP derived from GRASS-LUE was higher in the east and lower in the west of the MP. Grassland GPP was on average 205 gC m−2 over the MP between 2001 and 2020 with mean annual total GPP of 322 TgC yr−1. 30 % of the MP steppe showed a significant GPP increase. Growing season precipitation is the main factor affecting GPP of the MP steppe across regions. Anthropogenic factors (livestock density and population density) had greater effect on GPP than growing season temperature in pastoral counties in IM that take grazing as one of main industries. These findings can inform the status and trend of the productivity of MP steppe and help government and scientific research institutions to understand the drivers for spatial pattern of grassland GPP on the MP.

Seeds exhibit the most stable elemental composition with nitrogen addition in an Inner Mongolian grassland

Variation in biomass elemental composition of grassland plants may have important implications for ecosystem functioning in response to global change. However, relevant studies have mostly focused on variation of nitrogen (N) and phosphorus (P) concentrations in plant leaves, while few studies have evaluated other elements and plant organs of grassland species. Here, we examined the effects of N addition on multi-element concentrations, and analyzed their patterns across different organs (leaf, stem, root and seed) of five plant species in a steppe community of the Inner Mongolian grassland. Our results showed that seeds exhibited the most stable elemental composition with N addition, and that manganese (Mn) and iron (Fe) concentrations were substantially more variable than macro-elements in response to N addition. In particular, we identified a set of significant negative relationships between elemental concentrations and their corresponding CVs (coefficients of variation) for all plant organs as a whole and for each individual organ. We further found that changes in soil pH and the availability of soil nutrients contributed mostly to variation in the biomass elemental composition of major plants in this community. These findings are important for accurately assessing the effects of N deposition on the biochemical cycling of nutrient elements in grassland ecosystems, and provide critical clues for developing effective approaches to adaptively managing grassland resources as well as mitigating the impact of global change on the dryland ecosystems in the Mongolia Plateau.

Spatial Distribution Characteristics of Soil C:N:P:K Eco-Stoichiometry of Farmland and Grassland in the Agro-Pastoral Ecotone in Inner Mongolia, China

Ecological stoichiometry (ES) is an important index that reflects the balance of various elements in ecological processes. Therefore, it is of great significance to understand the soil nutrient cycle to clarify the environmental control of soil carbon (C), nitrogen (N), phosphorus (P), and potassium (K). In this study, we analyzed the spatial distribution of soil C, N, P, and K contents and the C:N:P:K stoichiometric characteristics of 0–20 cm and 20–40 cm of farmland and grassland in four agro-pastoral areas in Inner Mongolia. Spearman correlation was used to analyze the effects of environmental factors on the soil C:N:P:K stoichiometric relationship. The results showed that there was no fixed Redfield ratio for the soil stoichiometric relationship of farmland and grassland in Inner Mongolia, and the values were 15:2:1:9 to 145:10:1:26 and 25:1:1:29 to 228:15:1:65, respectively. The stoichiometric relationships between farmland and grassland were consistent with the law of geographical and spatial heterogeneity. The ratios of C:N, C:P, C:K, N:P, and N:K showed an N distribution from west to east, while the ratio of P:K showed a V distribution. The stoichiometric relationships in grassland soil were mainly affected by soil organic carbon and total nitrogen content, while those in farmland were mainly affected by total nitrogen and total phosphorus content. The annual mean precipitation has a significant effect on stoichiometric relationships in farmland, while the annual mean temperature has a more significant effect on grassland. In conclusion, the spatial distribution difference in the soil stoichiometric relationship in the agro-pastoral ecotone of Inner Mongolia was more significant than the difference in the land use pattern. The influences of annual mean temperature and annual mean precipitation on soil ecological stoichiometry were in accordance with the geographical spatial similarity law. Compared with grassland, the stoichiometric relationship of farmland soil was greatly affected by fertilization, and farmland in this region was mainly limited by carbon and nitrogen. Thus, field management should be carried out according to local conditions. This study is of great significance as it promotes the rational utilization of land resources and the sustainable development of agriculture.

A Physics-Based Method for Retrieving Land Surface Emissivities from FengYun-3D Microwave Radiation Imager Data

The passive microwave land surface emissivity (MLSE) plays a crucial role in retrieving various land surface and atmospheric parameters and in Numerical Weather Prediction models. The retrieval accuracy of MLSE depends on many factors, including the consistency of the input data acquisition time. The FengYun-3D (FY-3D) polar-orbiting meteorological satellite, equipped with passive microwave and infrared bands, offers time-consistent data crucial for MLSE retrieval. This study proposes a physics-based MLSE retrieval algorithm using all the input data from the FY-3D satellite. Based on the retrieved MLSE, the spatial distribution of the MLSE is closely correlated with the land cover types and topography. Lower emissivities prevailed over barren or sparsely vegetated regions, river basins, and coastal areas. Higher emissivities dominated densely vegetated regions and mountainous areas. Moderate emissivities dominated grasslands and croplands. Lower-frequency channels showed larger emissivity differences with different polarizations than those of higher-frequency channels in barren or sparsely vegetated regions. The MLSE across densely vegetated land areas, mountainous areas, and deserts showed small seasonal variations. However, woody savannas, grasslands, croplands, and seasonal snow-covered areas showed noticeable seasonal variations. For most land cover types, the differences between vertically and horizontally polarized emissivities remained relatively constant across seasons. However, certain grasslands in eastern Inner Mongolia and southern Mongolia showed clear seasonal variations. It is very difficult to verify the MLSE on a large scale. Consequently, the possible error sources in the retrieved MLSE were analyzed, including the brightness temperature errors (correlation coefficient ranging from 0.92 to 0.99) and the retrieved land surface temperature errors (Root Mean Square Error was 3.34 K and relation coefficient was 0.958).

Responses of soil bacterial functional group diversity to nitrogen enrichment in global grasslands

Soil microbial functional groups are closely linked to ecosystem functioning and are highly sensitive to global environmental changes. However, compared to the species diversity, how soil microbial functional group diversity responds to environmental changes remains poorly understood. Here, we investigated the nitrogen (N) effect on soil bacterial functional group diversity and predicted its spatial pattern in global grasslands. By re-analyzing publicly available 16S rRNA gene amplicon data from 38 N-addition experiments including 96 paired measurements across five continents, we found that N enrichment significantly leads to a more similar β-diversity but had no pronounced effect on α-diversity of soil bacterial functional groups. Global mapping with a random forest model revealed a clear spatial pattern of the N effect: ∼78 % of the global grasslands have shifted towards a more similar bacterial functional group β-diversity under contemporary N deposition rates, and in the regions particularly affected by high N deposition and vulnerable to global changes (e.g. the Eurasian steppe), the magnitude of change was greater. These results make a step in understanding soil microbial functional group diversity in addition to species diversity in the face of environmental changes, and provide more knowledge and rationale for the conservation of soil microbial functional diversity hotspots in global grasslands.

Extreme drought alters methane uptake but not methane sink in semi-arid steppes of Inner Mongolia

Global climate change, particularly drought, is expected to alter grassland methane (CH4) oxidation, a key natural process against atmospheric greenhouse gas accumulation, yet the extent of this effect and its interaction with future atmospheric CH4 concentrations increases remains uncertain. To address this research gap, we measured CH4 flux during an imposed three-month rain-free period corresponding to a 100-year recurrence drought in soil mesocosms collected from 16 different Eurasian steppe sites. We also investigated the abundance and composition of methanotrophs. Additionally, we conducted a laboratory experiment to explore the impact of elevated CH4 concentration on the CH4 uptake capacity of grassland soil under drought conditions. We found that regardless of the type of grassland, CH4 flux was still being absorbed at its peak, meaning that all grasslands functioned as persistent CH4 sinks even when the soil water content (SWC) was <5 %. A bell-shaped relationship between SWC and CH4 uptake was observed in the soils. The average maximum CH4 oxidation rate in the meadow steppe was higher than that in the typical and desert steppe soils during extreme drought. The experimental elevation of atmospheric CH4 concentration counteracted the anticipated reduction in CH4 uptake related to physiological water stress on methanotrophic soil microbes under the drought stress. On the contrary, we found that across the regional scale, nitrogen, phosphorous, and total soil organic content played a crucial role in moderating the duration and magnitude of CH4 uptake with respect to SWC. USC-γ (Upland Soil Cluster γ) and JR-3 (Jasper Ridge Cluster) were the dominant group of soil methanotrophic bacteria in three types of grassland. However, the methanotrophic abundance, rather than the methanotrophic community composition, was the dominant microbiological factor governing CH4 uptake during the drought.

Moderate grazing increased carbon, nitrogen and phosphorus storage in plants and soil in the Eurasian meadow steppe ecosystem

The effects of grazing on the cycling of carbon (C), nitrogen (N) and phosphorus (P) in grassland ecosystems are complex. Uncertainty still exists as regards the allocation of C, N and P storage amounts in grazed ecosystems in Inner Mongolia, situated at the eastern end of the Eurasian dryland. Based on the long-term cattle grazing experimental platform in the Hulun Buir meadow steppe of Inner Mongolia, a 3-year (2019–2021) field control experiment was conducted to assess how the grazing intensity influenced the quantities of C, N and P stored in canopy biomass, root, litter and soil compartments. We examined the relationships between the different pools and their regulatory pathways at the ecosystem level across six grazing intensities. In general, grazing increased the aboveground N and P contents but decreased the aboveground biomass C content and nutrient storage amounts in aboveground biomass, roots and litter. The grazing intensity of 0.34 AU ha−1 increased soil organic carbon, total nitrogen and total phosphorus storage amounts, with the soil accounting for 98 % of total reserves on average. Grazing affected soil pH， nutrient contents, above- and belowground biomass and soil environmental factors such as soil bulk density, which in turn affected C, N and P storage in the ecosystem according to the results of the structural equation model; therefore, grazing intensity can be an important factor regulating the input and output of nutrients in the ecosystem. In the future, for adaptive management of grasslands, moderate grazing could effectively increase C, N and P storage in meadow steppe ecosystems and ensure the nutrient balance and long-term sustainable development.

Nitrogen deposition mediates more stochastic processes in structuring plant community than soil microbial community in the Eurasian steppe.

Anthropogenic environmental changes may affect community assembly through mediating both deterministic (e.g., competitive exclusion and environmental filtering) and stochastic processes (e.g., birth/death and dispersal/colonization). It is traditionally thought that environmental changes have a larger mediation effect on stochastic processes in structuring soil microbial community than aboveground plant community; however, this hypothesis remains largely untested. Here we report an unexpected pattern that nitrogen (N) deposition has a larger mediation effect on stochastic processes in structuring plant community than soil microbial community (those <2 mm in diameter, including archaea, bacteria, fungi, and protists) in the Eurasian steppe. We performed a ten-year nitrogen deposition experiment in a semiarid grassland ecosystem in Inner Mongolia, manipulating nine rates (0-50 g N m-2 per year) at two frequencies (nitrogen added twice or 12 times per year) under two grassland management strategies (fencing or mowing). We separated the compositional variation of plant and soil microbial communities caused by each treatment into the deterministic and stochastic components with a recently-developed method. As nitrogen addition rate increased, the relative importance of stochastic component of plant community first increased and then decreased, while that of soil microbial community first decreased and then increased. On the whole, the relative importance of stochastic component was significantly larger in plant community (0.552±0.035; mean±standard error) than in microbial community (0.427±0.035). Consistently, the proportion of compositional variation explained by the deterministic soil and community indices was smaller for plant community (0.172-0.186) than microbial community (0.240-0.767). Meanwhile, as nitrogen addition rate increased, the linkage between plant and microbial community composition first became weaker and then became stronger. The larger stochasticity in plant community relative to microbial community assembly suggested that more stochastic strategies (e.g., seeds addition) should be adopted to maintain above- than below-ground biodiversity under the pressure of nitrogen deposition.

Estimation of the Carrying Capacity and Relative Stocking Density of Mongolian grasslands under various adaptation scenarios

Mongolia's vast grasslands, crucial for both environmental and economic stability, are currently facing challenges due to overgrazing, climate change, and land-use changes. Understanding and effectively managing their Carrying Capacity (CC) and Relative Stocking Density (RSD) is essential for maintaining ecological balance. This study rigorously evaluates the CC and RSD of Mongolia's grasslands through an innovative approach that integrates ecological models with socio-economic data, aimed at improving grazing management practices. Data from the National Agency for Meteorology and Environmental Monitoring validates the model, providing precise CC and RSD estimates at the Soum level from 2000 to 2019. The study reveals significant regional variations in CC: northern grasslands exhibit a high CC of 2.8 Sheep Units (SU) per hectare, contrasting with the fragile CC in some southern regions, like the Gobi Desert, where it is as low as 0.3 SU per hectare. Approximately 38.8 % of Mongolia's territory maintains a CC exceeding 1.0 SU per hectare, indicative of sustainable grasslands. In contrast, 41.7 % of the land, primarily in southern regions, shows CCs below 0.5 SU per hectare, highlighting ecosystem vulnerability. The RSD, reflecting livestock numbers relative to CC, averages 1.07, suggesting a high livestock concentration near Ulaanbaatar but a more sustainable density across 43.2 % of the country. The research also explores adaptation scenarios against desertification and degradation, as well as improving pasture accessibility, providing insights for future grassland management strategies. In conclusion, this study emphasizes the need for sustainable land management practices to balance carrying capacity and stocking rates, offering a vital tool for policymakers and stakeholders in grassland conservation.

Seasonal dynamics of arthropod communities during horse dung decomposition in Inner Mongolian grasslands

Seasonal dynamics of arthropod communities during horse dung decomposition in Inner Mongolian grasslands

Effect of Sterilization on the Change of Available Phosphorus During the Wetting and Drying Process

Wetting and drying are typical natural events in arid and semiarid areas. In order to explore the contribution of microorganisms to the change in soil phosphorus components during wetting and drying processes, soil incubation experiments were conducted on calcareous soil from Inner Mongolia grasslands. By comparing the change in various phosphorus fractions between sterilized and unsterilized soils, the microbial effect on the change in available phosphorus with soil moisture changes was studied. The results indicated that there was no significant difference in APi (NaHCO3-extractable inorganic phosphate) content between the two treatments. Sterilization caused the content of APo (NaHCO3-extractable inorganic phosphate) to significantly increase. These results suggested that soil microorganisms have a negligible influence on changes of soil available inorganic phosphorus (APi) in the present soil sample during the wetting and drying process. The change in APo may be related to the high-temperature and high-pressure sterilization processes. These results enrich our knowledge about the microbial influence on dynamics of soil available phosphorus during wetting and drying events.

Belowground Bud Bank Is Insensitive to Short-Term Nutrient Addition in the Meadow Steppe of Inner Mongolia

Belowground Bud Bank Is Insensitive to Short-Term Nutrient Addition in the Meadow Steppe of Inner Mongolia

Evaluation of green pastoral residence in Grassland of Inner Mongolia based on fuzzy mathematics

Based on the theory of rural habitat, the concept of green pastoral residence is proposed, and the green pastoral residence is taken as the research object. Besides, based on the current situation of grassland ecological environment and pastoral living environment in Inner Mongolia, the green pastoral residence evaluation index system is established by using the hierarchical analysis method, and a fuzzy comprehensive evaluation model is constructed combined with fuzzy mathematical theory. Through case analysis, the evaluation results of the two modeling methods of analytic hierarchy method and fuzzy analytic hierarchy method are compared, and the applicability of the two modeling methods is analyzed, and a multi-level decision-making method more suitable for the evaluation of green pastoral residence is obtained.

The Growth and Development of Safflower (Carthamus tinctorius L.) in the Conditions of the Dry Steppe of Eurasia

The Growth and Development of Safflower (Carthamus tinctorius L.) in the Conditions of the Dry Steppe of Eurasia

Alcidodes karelinii (Coleoptera: Curculionoidea: Molytinae): New weevil species for the fauna of Serbia

This paper reports the first findings of the allochthonous weevil species Alcidodes karelinii (Boheman, 1844) in Serbia. It is distributed throughout the Eurasian steppe belt, and recently it has been spreading westwardly. The specimens from Serbia were found thanks to citizen science in two localities in Vojvodina Province (North Serbia): Ada Municipality, North Banat District, December 16th , 2022, and March 16th , 2024; and the Village of Bački Brestovac, Odžaci Municipality, West Bačka District, September 25th, 2023.

ИСПОЛЬЗОВАНИЕ ПРИРОДНО-РЕСУРСНОГО ПОТЕНЦИАЛА И МЕЖРЕГИОНАЛЬНАЯ АСИММЕТРИЯ УСТОЙЧИВОГО РАЗВИТИЯ СУБЪЕКТОВ СТЕПНОЙ ЗОНЫ РОССИИ

Natural climatic conditions and natural resource potential are the key factors that determine the development sustainability ofthe steppe zone regions of Russia. The use of natural resource potential is a determinant in the interregional asymmetry of the socio-economic development of steppe regions. In today’s context, regional imbalances are becoming a national security problem, going beyond exclusively socialand economic issues and forming complex risks, challenges, and threats.The purpose of the study is to assess the impact of natural resource potential on the formation of interregional asymmetry of sustainabledevelopment of Russia’s steppe regions. The authors have compiled a database of indicators characterizing the state of natural resource potential(NRP) for 18 regions of the steppe zone. A rating assessment of the steppe zone regions by groups of indicators reflecting the use of NRP wascarried out based on the authors' methodology. The authors constructed a cartographic diagram of the results of rating assessment of the regions bygroups of NRP indicators and cluster analysis of the ratings of indicators characterizing NRP and the sustainable development goals (SDG). Therelationship between ratings of the NRP use and SDG indicators based on the calculated Spearman’s rank correlation coefficients was estimated.There is a negative trend in the dynamics of indicators of the forest resources state in the regions of the Russian steppe zone, and also areduction in the area of agricultural land (by 4% in the regions, on average).The study revealed that the ratings of the use of natural resource potential are interrelated: for the ‘water resources’ group of indicators, adirect connection was revealed with the ratings of the ‘mineral resources’ and ‘land resources’ groups of indicators. The ratings of six blocks ofsustainable development goals have a close direct connection with the rating of the use of mineral resources; more than half of the ratings of theblocks of sustainable development goals are connected with the rating of the use of water resources.