Accurately quantifying grazing intensity (GI) is crucial for assessing grassland utilization and supporting sustainable management. Traditional livestock-based approaches cannot capture the spatial heterogeneity of grazing or its dynamic response to climate variability. The objective of this study was to develop a remote sensing-based quantitative framework for estimating GI across the Inner Mongolian grasslands. The framework integrates MODIS vegetation indices, ERA5-Land climate variables, topographic factors, and field-measured data and GI was quantified as the proportional difference between potential and satellite-derived aboveground biomass (AGB), providing a spatially explicit measure of forage utilization. In this framework, potential AGB (AGBp) represents the climate-driven growth capacity under ungrazed conditions reconstructed using machine learning models, whereas satellite-derived AGB (AGBs) denotes the standing AGB remaining under current grazing pressure. Validation using 324 paired grazed–ungrazed plots demonstrated strong agreement between modeled and observed GI (R2 = 0.65, RMSE = 0.18). This AGB-difference-based approach provides an effective and scalable tool for large-scale rangeland monitoring, offering quantitative insights into grass–livestock balance, ecological restoration, and adaptive management in arid and semi-arid regions.

Grazing exclusion contributes to the restoration of degraded grassland, including its soil. Whether restoration merely affects the surface layer or also penetrates into the subsurface layer remains unclear. Therefore, taking the typical steppe and desert steppe in the Mongolian Plateau as cases, this study investigated the effects of grazing exclusion on soil microbial diversity, composition, and function in the soil surface (0-10 cm) and subsurface (10-30 cm). Bacterial diversity was higher in the surface layer than in the subsurface layer in the typical steppe, but the opposite was true in the desert steppe. Grazing exclusion significantly increased fungal diversity in the surface layer (typical steppe) or in both layers (desert steppe). Grazing exclusion significantly altered bacterial (Actinobacteria, Proteobacteria) and fungal (Basidiomycota, Ascomycota) community composition in both steppe types. In the typical steppe, both bacterial and fungal communities differed between soil layers, whereas only bacterial communities varied between soil layers in the desert steppe. Co-occurrence network stability correlated with bacterial (not fungal) community composition and was linked to soil nutrients (e.g., dissolved organic carbon, soil organic carbon, and total nitrogen) across steppe types and soil layers. Overall, our research showed that grazing exclusion showed higher proportion and stronger functioning of soil microbiome associated with plant growth promotion, nutrient acquisition, or pathogen suppression in the typical and desert steppes. The difference in microbiome between the surface layer and subsurface layer of the typical steppe depended on bacteria and fungi, while that difference only depended on bacteria for the desert steppe.

Dominant species occupy a pivotal role in plant community, influencing the structure and function of the ecosystem. The spatial distributions of dominant species can react to the effect of different grazing intensities, thereby reflecting their tolerance and adaptive strategies toward grazing. In this study, geostatistical methods were mainly used to study the spatial distribution characteristics of Stipa krylovii Roshev. and Leymus chinensis (Trin.) Tzvel. species at two interval scales (quadrat size 5 m × 5 m, 10 m × 10 m) and two treatments (free grazing, FG, 1.66 sheep·ha− 1·a− 1; control, CK, 0 sheep·ha− 1·a− 1) in typical steppe of Inner Mongolia. A systematic sampling method was used in each 100 m × 100 m representative sample plots to obtain the height, coverage, and density of all species in the community. The results showed that grazing altered the concentrated distribution of S. krylovii and the spatial mosaic distribution pattern of S. krylovii and L. chinensis while having no effect on the spatial clumped distribution of L. chinensis. It also found that the spatial distributions of dominant species are primarily affected by structural factors, and random factors such as long-term grazing led to a transition of S. krylovii from a concentrated distribution to a small patchy random pattern should not be overlooked. Our findings suggest that long-term grazing alters the spatial distribution pattern of dominant species and that adaptive strategies may be the key for maintaining the dominant role of structural factors.

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.

Leymus chinensis is a widely distributed species of Eurasian grasslands that is well adapted to a range of environmental conditions. In this study, we measured soil and plant chemical elements to examine the basis of the ecological adaptations of L. chinensis to temperate steppe. We sampled leaves of L. chinensis and soil layers at different latitudes in temperate steppe for three consecutive years from 2012 to 2014. One-way analysis of variance and linear regression were used to analyze the variation in foliar nitrogen (N) and phosphorus (P) contents and the N:P ratio in L. chinensis. The correlations between the foliar N:P ratio and the variation in soil total nitrogen (TN) and total P contents with latitudinal gradient were measured to explore the homeostasis stoichiometry of foliar N and P in L. chinensis. With increasing latitude, both the foliar N and P contents of L. chinensis showed parabolic trends with significant negative correlations. The population of L. chinensis was limited by N, and the soil TN content showed a significant increasing trend with the increase in the foliar N:P ratio. The variation in the foliar N:P ratio of L. chinensis was determined through the variation in the soil N content. In different latitude intervals, the foliar N, P, and N:P ratio of L. chinensis showed absolute stability and strong internal stability, and the values of H-N:P were high and similar in different latitudes. In conclusion, the population of L. chinensis in the temperate steppe is highly adaptable; and, thus, can maintain a dominant position in the variable environment and has a wide distribution range.

Due to climate change and global warming, the frequency of sandstorms in northern China is increasing. Stipa breviflora, a dominant species in Eurasian grasslands, can help prevent desertification from becoming more serious. Studies on S. breviflora cover a wide range of fields. To the best of our knowledge, the present study is the first to sequence, assemble, and annotate the S. breviflora genome. In total, 2,781,544 contigs were assembled, and 2,600,873 scaffolds were obtained, resulting in a total length of 649,849,683 bp. The number of scaffolds greater than 1 kb was 70,770. We annotated the assembled genome (>121 kb), conducted a selective sweep analysis, and ultimately succeeded in assembling the Matk gene of S. breviflora. More importantly, our research identified 26 scaffolds that may be responsible for the drought tolerance of S. breviflora Griseb. In summary, the data obtained regarding S. breviflora will be of great significance for future research.

The stoichiometric homeostasis of plant populations can reflect the adaptation and survival strategies of plant populations in a certain ecological environment, which is of great significance for maintaining ecosystem stability. In this paper, the Stipa grandis population on the eastern edge of Eurasian temperate steppe was taken as the research object. The one-way ANOVA analysis, linear regression analysis and correspondence analysis were used to analyze the change of nitrogen（N）, phosphorus（P） content and N/P ratio in Stipa grandis leaves, and the correlation between N/P ratio and soil total N, total P content and N/P ratio in soil along latitudinal gradient. At the same time, the stoichiometric homeostasis of nitrogen and phosphorus in Stipa grandis leaves was investigated. The results showed that:（1） The N content and N/P ratio in Stipa grandis leaves were significantly negatively correlated with the latitude gradient（P＜0.05）, while the P content in Stipa grandis leaves was not significantly correlated with the latitude gradient;（2） The N/P ratio in Stipa grandis leaves was greatly affected by total P in 20～30 cm soil layer and total N and N/P ratio in 10～20 cm soil layer, and there was a significant regression relationship between N/P ratio in Stipa grandis leaves and total N, total P and N/P ratio in the soil（P＜0.15）. there was a clear boundary between N/P ratio in Stipa grandis leaves in the middle-low latitude and in the high latitude;（3） The stoichiometric homeostasis indexes of N, P and N/P ratio in Stipa grandis leaves belonged to the absolute steady-state or weak steady-state type with strong stoichiometric homeostasis. In summary, Stipa grandis population had strong adaptability in the ecological transect area of the eastern edge of the Eurasian temperate steppe. It can adapt to the soil stoichiometric changes by maintaining its own stoichiometric homeostasis, and maintain its dominant position in the changing environment.

为探讨不同放牧强度下典型草原建群种羊草的空间分布特点及规律,本研究以中国农业科学院典型草原试验站羊草植物种群为研究对象,设置对照区(CK)、轻度放牧区(LG)、中度放牧区(MG)和重度放牧区(HG)4个放牧强度,结合箱式图和多重分形等方法展开研究.结果表明:羊草植物种群在不同放牧强度下的空间分布存在多重分形特征;羊草植物种群在中度和重度放牧区空间分布呈现复杂性和不均匀性,而其在对照和轻度放牧区空间分布相对均匀化;随着放牧强度的增大,羊草种群空间分布由均匀转向聚集状态,生态位宽度较为一致,个体间的竞争强度降低.无论放牧强度如何变化,典型草原的羊草种群空间分布特征以大概率子集为主,且其在典型草原试验站放牧强度试验的群落中仍占有主导地位.

Abstract Drought has a great impact on global terrestrial ecosystems. A large number of studies have shown that the impact of drought on vegetation growth has a lagged and cumulative effect, but it is unclear how much it contributes to different vegetation types. Therefore, based on the standardized precipitation evapotranspiration index (SPEI) base version 2.5 and the Global Inventory Monitoring and Modeling System (GIMMS3g) normalized difference vegetation index (NDVI) datasets, this study aimed to analyze the response process of different vegetation types to the cumulative and lagged effects of drought in the Mongolian Plateau during 1982–2015 using Pearson correlation and the Mann–Kendall mutation method and deeply explore the magnitude of the contribution of drought cumulative and lagged effects on vegetation using the multiple regression method. Our results show that, from 1982 to 2015 as a whole, NDVI showed an insignificant increasing trend, and SPEI had a significant mutation in 1998 and showed an insignificant increasing trend before and after 1998. Before 1998, the cumulative months were shorter (1–3 months) in the central steppe and agricultural vegetation zones, and the lagged months were longer (10–12 months) in the southeastern steppe and northeastern forest zones; after 1998, the cumulative months of NDVI increased (7–12 months) and the lag months decreased (3–8 months) in most vegetation zones. A comparison of the contribution of drought accumulation and lag to NDVI revealed that the main driver of NDVI has shifted from lagged to cumulative effect.

定量获取地表植被高精度时序及空间覆盖的叶面积指数(Leaf Area Index,LAI)是生态监测及农业生产应用的重要研究内容.通过使用Moderate Resolution Imaging Spectroradiometer(MODIS)植被冠层多角度观测MOD09GA数据及叶面积指数MOD15A2数据,发展了一种参数化的叶面积指数遥感反演方法并完成了必要的检验分析.研究使用基于辐射传输理论的RossThick LiSparse Reciprocal(RTLSR)核驱动模型及Scattering by Arbitrarily Inclined Leaves with Hotspot(SAILH)模型进行植被冠层辐射特征的提取,使用Anisotropic Index(ANIX)异质性指数作为指示植被冠层二向反射分布Bidirectional Reflectance Distribution Function(BRDF)的辅助特征信息,发展了基于数据机理(Data-Based Mechanistic,DBM)的植被叶面积指数建模和估算方法.通过必要的林地、农作物、草地植被实验区反演及数值分析可得知:①时间序列多角度遥感观测数据结合数据机理的叶面积指数估算方法,可实现模型参数的时序动态更新,改进叶面积指数估算结果的时序完整性及精度.②异质性指数可以用做指示植被冠层二向反射分布特征信息,可降低因观测数据几何条件差异所导致的反演结果不确定情况,同时能够补充植被时序生长过程表现的植被结构变化等动态特征.经研究实践,可将算法应用于时空尺度的叶面积指数估算,并能够为生态、农业应用提供植被的高精度遥感监测指标.

As a grassland type distributed in the desert steppe with warmer climate in the steppe region of central Asia, Stipa breviflora steppe has the following characteristics, i.e. transition and vulnerability. Therefore, it is susceptible to global climate changes and anthropogenic disturbances. The resistance and resilience of a plant community to the disturbances or climate changes mainly depend on plant functional traits of the dominant species. Yet there are few studies focus on the interaction between annual precipitation and grazing pressure on the variation of plant traits of desert steppe. We investigated the functional traits of S. breviflora under contrasting annual precipitations (wet and dry years) and different long-term grazing intensities (no grazing, light grazing, moderate grazing, MG, and heavy grazing, HG), and revealed the influence of grazing and the precipitation on the variability of functional traits of S. breviflora. Moreover, we discussed the vulnerable grassland type’s adaptation mechanism to grazing disturbances and precipitation changes, and its grazing adaptation strategy under different annual rainfall precipitation conditions. Plant height, coverage, above-ground biomass, leaf length, single leaf area of S. breviflora, were sensitive to grazing interference and precipitation, while leaf dry matter content, specific leaf area, and leaf nitrogen content were inert traits. S. breviflora’s resistance and resilience in response to grazing disturbance strongly depended on rainfall conditions. In the dry year, the functional traits of S. breviflora showed higher plasticity in responses to grazing treatment, in which moderate interference was favorable for the compensatory growth of S. breviflora. The functional traits of S. breviflora were not sensitive to the drastic changes of precipitation in grazing exclusion plot for many years. It was concluded that grazing in dry year had an adverse effect on S. breviflora desert steppe, and that light grazing or banning grazing in dry years is a better management practice for the desert steppe.

以欧亚温带草原东缘生态样带为平台,以样带上未放牧和重度放牧配对样地为研究对象,开展重度放牧对欧亚温带典型草原土壤氮矿化及其温度敏感性的影响研究。结果表明:（1）在室内培养条件下,土壤氮积累量和土壤净氮矿化速率呈现出干燥度指数较大的样点显著大于干燥度指数最低的样点（P＜0.05）。在相对湿润的样点,土壤氮素矿化周转速率较快;（2）重度放牧对不同样点土壤氮积累量和土壤氮矿化速率的影响是不同的。在干燥度指数较高样点,重度放牧样地土壤铵态氮减少量和速率较未放牧样地低（P＜0.05）,重度放牧显著降低了土壤硝态氮积累量、无机氮积累量、硝化速率、净氮矿化速率（P＜0.05）;在干燥度指数较低样点,重度放牧样地土壤铵态氮减少量和速率较未放牧样地高（P＜0.05）,重度放牧对土壤硝态氮积累量、无机氮积累量、硝化速率、净氮矿化速率影响不大（P＞0.05）;（3）土壤氮矿化作用温度敏感性(Q 10 )变化范围在1.61—2.06,重度放牧对Q 10 无显著影响。随着纬度的升高,Q 10 呈升高趋势。Q 10 与基质质量指数以及表观活化能与基质质量指数均呈显著的负相关关系（P＜0.05）;（4）土壤硝态氮积累量、无机氮积累量、硝化速率、净氮矿化速率对重度放牧的响应比与干燥度指数呈极显著负相关（P＜0.01）,重度放牧对欧亚温带典型草原土壤氮矿化的影响受气候条件（温度和降水）的调控。

治理草原退化是我国草原管理的重点和难点.我国目前关于草原退化判断、退化程度、原因及治理等系列问题的确定几乎皆以科学研究结果为依据,而忽视了牧户作为草原直接使用者和管理者的重要性.牧户对草原有自己的判断和认知,其与科学方法研究之间的矛盾已经影响到草原生态保护政策的有效实施.以内蒙古东部草甸草原牧户尺度草原为研究对象,借助牧户调研和野外调查相结合的方法,将牧户划分为高、中、低3个经济水平,并运用Condition-Vigor-Organization-Resilience (CVOR)指数评价法,分析评价草原生态系统健康状况.研究结果显示,牧户对草原健康状况的感知主要从植被、土壤、牲畜等方面,与科学方法评价指标选取具有相似性;牧户感知和CVOR指数法评价结果具有一致性,均判定草原生态系统呈现不同程度退化;统计检验显示牧户对植被、土壤、牲畜影响等指标变化感知方面均不存在显著差异(P＞0.05),CVOR指数法下不同经济水平牧户草场健康指数之间亦无显著差异(P＞0.05),两种方法均显示不同经济水平牧户草场退化程度无显著差异(P＞0.05).研究证实了牧户感知在指标选取、评价结果方面具备用于准确评价草原健康状况的可行性和可信度.两种方法相互补充,将有利于更加准确、实时动态监测和评价牧户尺度草原生态健康状况,为调整优化畜牧业生产实践提供指导和草原生态保护和建设政策的有效实施提供保障.

Although winter lambing practices (WL) have been shown to be a ‘win-win’ strategy for reducing the degradation of grasslands and improving herder livelihood in the pastoral regions of China, the adoption rate is still low. A survey was conducted to explore herders’ opinions of WL and other factors which influenced the adoption in the desert steppe region of Inner Mongolia, China. Herders who have spring lambing practices generally hold unfavourable opinions about WL. Most have only heard about WL but did not understand the detailed information of implementation or how it increases income. Herder ethnical background, distance to market and neighbours’ choices significantly affected the adoption rate. Han herders were more likely to adopt WL than Mongolian herders. Proximity to market led herders to be more market-focused and to adopt WL. Herders were more inclined to make the same choices as their neighbours. The results showed that herders were prepared to change and were carefully assessing the gains and losses of adopting WL. Results had implications for improving the adoption rate for WL and other livestock management practices in China.

Niche and ecological attributes of plant population of Inner Mongolia Plateau desert steppe under free grazing (CG)were analyzed compared with enclosure (CK).The results showed that the total niche breadth of the dominant species Stipa breviflora,Cleistogenes songorica and Allium polyrhizum was significantly higher than those of other plant populations both in time and spatial scale,which were still dominant in the community.In the time scale,the degradation characteristics of grassland in enclosed area were obvious,and moderate continuous grazing can delay it in a certain way.The total niche breadth was in a rectangular relationship with the niche breadth of the enclosed area and the continuous grazing ar-ea.The niche breadth of Stipa breviflora and Cleistogenes songorica were increased by continuous graz-ing,while that of Allium polyrhizum was decreased.The ecological attributes can reflect the evolution di-rection of the plant population in community,and the ecological response rate based on the time scale can help to understand and reflect the development and demise process of the plant population in the time axis.

Agricultural flood disaster risk assessment plays a vital role in agricultural flood disaster risk management. Extreme precipitation events are the main causes of flood disasters in the Midwest Jilin province (MJP). Therefore, it is important to analyse the characteristics of extreme precipitation events and assess the flood risk. In this study, the Multifractal Detrended Fluctuation Analysis (MF-DFA) method was used to determine the threshold of extreme precipitation events. The total duration of extreme precipitation and the total extreme precipitation were selected as flood indicators. The copula functions were then used to determine the joint distribution to calculate the bivariate joint return period, which is the flood hazard. Historical data and flood indicators were used to build an agricultural flood disaster vulnerability surface model. Finally, the risk curve for agricultural flood disasters was established to assess the flood risk in the MJP. The results show that the proposed approaches precisely describe the joint distribution of the flood indicators. The results of the vulnerability surface model are in accordance with the spatiotemporal distribution pattern of the agricultural flood disaster loss in this area. The agricultural flood risk of the MJP gradually decreases from east to west. The results provide a firm scientific basis for flood control and drainage plans in the area.

In this paper,the ecological stoichiometric characteristics of the main plant population of Stipa breviflora,Cleistogenes songorica,Allium polyrhizum,Convolvulus ammannii and Neopallasia pectinata were studied.To discusses main plant populations of ecological stoichiometry characteristics and coefficient of variation in different stages, revealing the desert grassland of different species, different development stage of C, N, P content and its measurement, for the large scale, a wide range of ecological stoichiometry study provides the basis.The main plant population of N/P was lower 14% in Stipa breviflora desert steppe.The main plant growth was limited by N. The seasonal variation of leaf C, N and P and C:N, C:P and N:P mass ratios were also dramatically different. The coefficient of variation (CV) of leaf C, N and P contents and C:N, C:P and N:P mass ratio was P (36.88%)>C/P (33.97%)>N/P (27.85%)>N (23.81%)>C/N (21.58%)>C (6.17%). The range of seasonal CV values for C and C/N was 2.58%~14.09%, 14.85%~29.92%, respectively, and P was 26.39%~51.56%, N was 18.39%~36.51%, C/N and C/P was 14.85%~29.92%, 26.29%~43.38%, respectively. The species of leaf N and P content showed significantly higher than in other seasons in the early stage of growth (P<0.05), and showed the leaf C content was lower than the growth in early growth stage, leaf C:N and C:P increased gradually with the growth time. Plant leaves C, N and C/N, C/P, N/P are mainly affected by plant species, followed by the interaction between plant species and months, and finally for the impact of the month, while the plant P content is mainly affected by the month.

The research object of the study was meadow steppe in Chagannuoer village in Wuzhuer country in the northwest of Chenbaerhu Banner.The date of meteorological (precipitation and temperature) and aboveground biomass (enclosed area and free grazing area) in growing season(May~August) for ten years(2004~2013) were selected.The results showed that the standing crop of grassland was not only affected by precipitation and temperature, but also by the intensity of grazing.The aboveground biomass was closely related to precipitation and temperature.The effect of precipitation on the aboveground standing crop was stronger than temperature.The effect of effective precipitation on the aboveground standing crop of the grassland was enlarged and delayed.