Abstract Alpine grasslands are cold and hypoxic, typically lacking symbiotic nitrogen fixation. Nonetheless, they often maintain high nitrogen stocks, which suggests an important role for asymbiotic nitrogen fixation (ANF). However, the ANF rates of soil or plant leaves and their driving factors in alpine grasslands remain unclear. We quantified the ANF rates in soil and plant leaves, the soil stoichiometry and the nifH based community composition and abundance across alpine grasslands (swamp meadow, alpine meadow, and alpine steppe) along an altitudinal gradient between 3100 and 4300 m above sea level (a. s. l). The ANF rates in swamp and alpine meadows were faster than in alpine steppe. Diazotroph communities were dominated by Proteobacteria (85%) and Actinobacteria (12%), and 72 nifH OTUs assigned to Cluster II (anfH/vnfH-like) suggested the potential presence of alternative nitrogenase-related homologs. Specialist taxa in soil ANF bacteria were influenced mainly by stochastic processes and exhibited faster transition rates than generalists. Random forest analyses identified soil pH, nifH diversity and composition, soil stoichiometry, and molybdenum as key predictors of soil ANF. Estimated annual nitrogen inputs were 4.0, 3.1, and 0.5 kg N ha-1 yr-1 in alpine meadow, swamp meadow, and alpine steppe, respectively. Our results indicate that ANF represents a significant nitrogen input pathway in alpine grasslands and should be incorporated into nitrogen cycling and regional nitrogen budgets.

Abstract The yak ( Bos grunniens ) serves as an exceptional model for studying high-altitude adaptation mechanisms due to its evolutionary success in the hypoxic environment of the Qinghai-Tibet Plateau. Previous research has largely focused on genetic and physiological traits of yaks; however, the interactions between rumen microbiota and host physiology under hypoxic conditions are poorly understood. As the largest digestive organ in ruminants, the rumen and its microbiota play a central role in digestion and host nutrition. In this study, a comparative analysis of digestive metabolism and rumen microbiota was carried out in yaks and cattle ( Bos taurus ) under two distinct atmospheric oxygen scenarios: baseline (2,200 m) and hypoxic (3,800 m). Our findings reveal that yaks have developed unique microbial strategies to cope with energy deficits in hypoxic stress. These strategies include a shift in rumen microbiota toward amino acid degradation, providing more available energy substrates for host utilization, and enhanced long-chain fatty acid biosynthesis, enabling more efficient energy storage and utilization. This improves energy acquisition in yaks despite their reduced nutritional intake. However, this metabolic adaptation comes at a physiological cost - reduced microbial crude protein (MCP) synthesis, leading to elevated ruminal NH 3 -N levels, and increased fatty acid metabolism and urea cycle activity contributing to hepatic stress. Our results showed that under high-altitude conditions, yak MCP synthesis decreased by 47.3%; and ruminal NH3-N and serum ALT (a hepatic stress marker) increased by 147.2 and 19.7%, respectively. This study presents evidence of potential metabolic trade-offs in high-altitude adaptation, indicating that yaks may optimize microbially mediated energy production at the cost of liver health. These insights deepen our understanding of host-microbiome coevolution mechanisms in extreme environments and highlight biological costs associated with adaptation to high altitudes.

Background. Himalayan grasslands are biodiversity hotspots vital for soil stabilization, carbon cycling and herbivore sustenance, and yet, studies on seasonal plant-soil-microbe dynamics remain limited in the Western Himalayas. Methods. We examined seasonal variations in vegetation, soil properties and microbial diversity in subalpine (SAL, Pir Chinasi) and alpine (AL, Ratti Gali) grasslands. Results. Vegetation communities shifted seasonally, with summer being dominated by Sibbaldia cuneata Hornem. ex Kuntze in SAL and Bistorta affinis (D. Don) Greene in AL, while winter shifted to Poa alpina in SAL. Biodiversity indices were greater (p < 0.05) in summer for SAL, while only richness differed seasonally in AL. Soil moisture correlated with soil organic carbon in winter (r = 0.642, p < 0.01) and in summer (r = 0.756, p < 0.001). Microbial alpha diversity peaked in summer, with communities dominated by Actinomycetota and Pseudomonadota. Microbial composition correlated with different soil properties seasonally with pH and micronutrients in summer and total potassium and phosphorus in winter. Beta diversity differed between grasslands (p = 0.001), while functional profiles remained stable seasonally, indicating metabolic resilience. Conclusions. Seasonal shifts and grassland type drive the structure of Himalayan ecosystems. Although plant and microbial communities were seasonally dynamic, their core metabolic functions were stable, indicating functional resilience essential for stability of the vulnerable high-altitude ecosystems.

Climate change and overgrazing are accelerating grassland degradation and the concomitant encroachment of poisonous plants worldwide. Effective restoration of degraded grassland and management of poisonous plants rely critically on identifying the ecological thresholds of poisonous plants encroachment, but this information remains uncertain. Here, we analyzed the responses of 20 structural and functional grassland variables to the increasing coverage of poisonous plants across 465 standardized field plots in alpine grasslands on the Qinghai-Tibetan Plateau. Asynchronous responses emerged across ecosystem variables: root productivity declined at 10% poisonous plants coverage, biodiversity decreased at 30%, but soil nutrients increased beyond 50%. In addition, ecosystem multifunctionality and plant-soil network also recovered slightly after 50%. We propose that 50% coverage represents a critical threshold where poisonous plants transition from a driver to a mitigator of degradation. We suggest stage-specific management strategies to mitigate poisonous plants encroachment in grasslands based on these thresholds.

Jenny milk is characterized by low fat content and individual variability. To test the association between blood and milk lipid profiles between jennies with high-fat (HF) and low-fat (LF) content in milk, we compared blood and milk lipid compositions between HF and LF jennies on the same feeding and management regimes. Milk fat yield and milk fat content were greater in the HF than LF group, but milk yield, lactose and protein contents, density, pH, and somatic cell count did not differ between groups. Milk fat content was correlated negatively with density and positively with pH and SCC. In blood, glycerophospholipids accounted for more than 50% of total lipids (TL), while glycerolipids accounted for more than 50% of TL in milk. The composition or concentration of TL and lipid subclasses in the blood did not differ between the HF and LF groups, with only 11 lipid species differing. In milk, the composition and concentration of TL, 17 lipid subclasses, and 131 lipid species differed between groups. The main upregulated lipid compounds were triglycerides which consisted of C16 and C18 fatty acids, while the downregulated compound was 1,2-distearoyl-sn-glycerol (DSG). These differential lipids were involved in 8 metabolic pathways, including cholesterol metabolism, vitamins digestion and absorption, GL metabolism, regulation of lipolysis in adipocytes, fat digestion and absorption, and thermogenesis. We concluded that: 1) blood lipidomic profile cannot be used to predict milk fat content and composition in jenny; 2) the synthesis of jenny milk fat is influenced primarily by mammary tissue.

The impacts of reclamation and fertilization of sandy grassland on soil microbial communities and functional groups related to carbon (C) and nitrogen (N) cycling are not well understood. To fill this gap, three types of fertilizers, namely, chemical fertilizer (CF), manure (M), and chemical fertilizer plus manure (CF_M), were applied annually for five years to reclaimed sandy cropland planted to maize. Nearby sandy grassland without fertilizer and maize was included as a control. Soil microbial communities and processes, soil properties, and aboveground biomass (AGB) were determined. Soil microbial Chao richness was lowest in soil without fertilizer and maize. Fungal Shannon diversity was lowest with chemical fertilizer plus manure, while soil microbial Chao richness and bacterial Shannon diversity were not influenced by fertilization. Reclamation and fertilization increased AGB, which was greatest with chemical fertilizer plus manure and was more than seven times greater than that of sandy grassland. Soil extracellular enzyme activities increased with chemical fertilizer plus manure. Fertilization enhanced C cycle functional groups by decreasing soil bulk density and elevating soil total N, total carbon, Firmicutes abundance, and bacterial Chao richness, but lessened N cycle functional groups by decreasing Nitrospirota abundance. Microbial functional category groups associated with C and N cycles responded differently to reclamation and fertilization of sandy soil, which, in turn, affected soil carbon sequestration and nutrient availability.IMPORTANCEReclamation and fertilization of sandy grassland altered biogeochemical functions by influencing microbial communities and functional category groups related to carbon (C) and nitrogen (N) cycling. Reclamation and fertilization could lead to the reduction of soil C content and insufficient soil N by altering functional category groups, which would be a potential risk leading to sandy grassland degradation. These findings not only improve our understanding of the consequences of sandy grassland reclamation and fertilization on ecosystem processes, but are also important for predicting soil C sequestration and nutrient cycling and for developing strategies to prevent degradation of sandy grassland.

Abstract The traditional grazing system of the Qinghai-Tibet Plateau faces challenges such as feed shortages, despite the abundance of pastures during the warm season. However, the impact of supplemental feeding on yak meat quality during this period still requires further investigation. A total of 30 male yaks (with similar genetic backgrounds, aged 2.5–3 years, weighing 94.56 ± 3.9 kg) were evenly and randomly assigned to two groups: the traditional grazing group (G) and the supplemental feeding group (SF). This study evaluated the effects of supplementation on yak meat quality and metabolic characteristics, aiming to identify effective dietary strategies to improve the physical and nutritional quality of yak meat. Non-targeted metabolomics (UHPLC-QE-MS) was used to analyze biomarkers of meat quality. Results revealed that the SF group exhibited superior meat quality, with a 39.6% reduction in shear strength, a 22.4% reduction in cooking loss, a 15% increase in PUFA/SFA ratios, and an 18% increase in essential amino acid content. Metabolomic profiling indicated distinct differences between the two groups, with the SF group demonstrating significant upregulation of beneficial metabolites (e.g., pyruvic acid, L-tyrosine, and eicosapentaenoic acid) and downregulation of harmful metabolites (e.g., sulfates). These changes improved protein turnover, lipid metabolism, and glycolytic activity, enhancing meat tenderness, flavor, and nutritional value. This study provides novel insights into the metabolic mechanisms underlying feed-induced quality changes, highlighting the practical value of supplemental feeding in overcoming the limitations of traditional grazing systems and reducing ecological pressure on grasslands.

The donkey has been receiving increasing attention due to its milk production, and the manipulation of milk fat content has become one of the key current topics. We tested the hypothesis that the dietary proportions of lipids, non-fiber carbohydrates (NFC) and neutral detergent fibers (NDF) affect milk composition in jennies. Twenty-four lactating jennies of similar age, weight (180 +/- 4.1 kg) and foaling date were assigned randomly into three dietary groups: high lipids and NDF with low NFC (HLF); medium lipids and NDF with intermediate NFC (MLF); and low lipids and NDF with high NFC (LLF). The three diets were isoenergetic and isonitrogenous, and the study consisted of 14 days of adaptation and 56 days of measurements. Milk, blood and fecal samples were collected to determine the effects of dietary intake on milk composition, blood metabolites, and fecal short-chain fatty acids and microbiota. The percentage (P = 0.007) and yield (P = 0.013) of milk fat in the HLF group were greater than in the MLF and LLF groups, while the percentages of milk protein (P < 0.001) and lactose (P < 0.001) were greater in the MLF group than in the HCS and LLF groups. The concentrations of milk medium-chain fatty acids (FA) (P = 0.047), polyunsaturated FA (P = 0.021) and unsaturated FA (UFA) (P = 0.036) were greater in the HLF than LLF group, and the feed conversion ratio (FCR) of & sum;<= C14 FA was greater (P = 0.003) in the HLF and MLF groups than the LLF group, while the FCR of & sum;>= C18 FA in the LLF group was greater (P = 0.046) than in the HLF group. Most differential blood metabolites between HLF and MLF or between HLF and MLF groups were related to lipid metabolism. Fermentation parameters in the rectal feces did not differ among groups. The abundances of the phylum Spirochaetes (P < 0.001) and the genus Treponema (P < 0.001) in the feces of the MLF and LLF groups were lesser, but the abundances of Prevotella (P < 0.001) and Ruminococcus (P = 0.009) in the MLF and LLF groups were greater than in the HLF group. A high proportion of dietary lipids and NDF increased milk fat content, UFA concentrations, feed conversion ratio of & sum;<= C14 FA, and abundance of fecal cellulolytic bacteria; whereas, a high proportion of dietary NFC increased blood FA metabolites and the abundance of pro-inflammatory bacteria. Dietary composition can influence milk composition in jennies, and high proportions of lipids and NDF can increase milk fat content.

Yaks are well-adapted to the harsh environment of the Tibetan plateau, and they emit less enteric methane (CH4) and digest poor-quality forage better than cattle. To examine the potential of yak rumen inoculum to mitigate CH4 production and improve digestibility in cattle, we incubated substrate with rumen inoculum from yak (YRI) and cattle (CRI) in vitro in five ratios (YRI: CRI): 0:100 (control), (2) 25:75, (3) 50:50, (4) 75:25 and (5) 100:0 for 72 h. The YRI: CRI ratios of 50:50, 75:25 and 100:0 produced less total gas and CH4 and accumulated less hydrogen (H2) than 0: 100 (control) at most time points. From 12 h onwards, there was a linear decrease (P < 0.05) in carbon dioxide (CO2) production with increasing YRI: CRI ratio. At 72 h, the ratios of 50:50 and 75:25 had higher dry matter (+7.71% and +4.11%, respectively), as well as higher acid detergent fiber digestibility (+15.5% and +7.61%, respectively), when compared to the 0:100 ratio (P < 0.05). Increasing the proportion of YRI generally increased total VFA concentrations, and, concomitantly, decreased the proportion of metabolic hydrogen ([2H]) incorporated into CH4, and decreased the recovery of [2H]. The lower [2H] recovery indicates unknown [2H] sinks in the culture. Estimated Gibbs free energy changes (∆G) for reductive acetogenesis were negative, indicating the thermodynamic feasibility of this process. It would be beneficial to identify: 1) the alternative [2H] sinks, which could help mitigate CH4 emission, and 2) core microbes involved in fiber digestion. This experiment supported lower CH4 emission and greater nutrient digestibility of yaks compared to cattle. Multi-omics combined with microbial culture technologies developed in recent years could help to better understand fermentation differences among species.

Soil organic matter composition and microbial communities are key factors affecting ecosystem multifunctionality (EMF) during ecosystem restoration. However, there is little information on their interacting mechanisms in degraded and restored meadows. To fill this knowledge gap, plant, root and soil samples from alpine swamp meadows, alpine Kobresia meadows, severely degraded alpine meadows, short-term restored meadows (< 5 years) and long-term restored meadows (6–14 years) were collected. We leveraged high-throughput sequencing, liquid chromatography and mass spectrometry to characterize soil microbial communities and soil organic matter composition, measured microbial carbon metabolism and determined EMF. It emerged that the similarity of soil microorganisms in meadows decreased with increasing heterogeneity of soil properties. Dispersal limitation and ecological drift led to the homogenization of the bacterial community. Based on co-occurrence network analysis, an increase in microbial network complexity promoted EMF. Root total phosphorus and soil organic matter components were the key predictors of EMF, while organic acids and phenolic acids increased the stability of the microbial network in long-term restored meadows. Carbon metabolism did not increase in restored meadows, but the niche breadth of soil microorganisms and the utilization efficiency of small molecular carbon sources such as amino acids did increase. These findings emphasize the importance of soil organic matter composition in ecological restoration and that the composition should be considered in management strategies aimed at enhancing EMF.

Climate warming and precipitation generally enhance greening on the Qinghai-Tibetan Plateau (QTP). However, recent studies suggested that the greening trend is decelerating, while its underlying driving mechanisms remain unclear. We speculate that this may be related to an asynchrony between precipitation and soil water content in certain regions, but this is poorly understood. To fill this gap, we studied vegetation greening on the QTP using time series satellite-derived AVHRR NDVI (normalized difference vegetation index) data of climate and soil water content for the past 39 years. NDVI increased over the whole period; however, it displayed a downward trend after the year 2000 compared with the previous 19 years. Asynchronous changes in precipitation and soil water content decelerated vegetation greening. Non-woody species responded stronger to asynchrony than woody species, with meadows being most affected and forests the least. We concluded that with global warming, soil water content may decrease in areas on the Qinghai-Tibetan Plateau, and that vegetation greening may decelerate in the future.

Sustainable grassland grazing is important for the livelihood of many herders, yet few studies have examined the effect of grazing under different climatic conditions on a large scale. To fill this gap, a meta-analysis was employed using data from published studies on livestock grazing grasslands in China. China has many types of grasslands with a wide range of climatic conditions and, therefore, the results are applicable for grasslands worldwide. Different climatic areas were identified in which arid and humid grasslands were based on K & ouml;ppen-Geiger climate classifications of biomes. It emerged that the effects of grazing on plant diversity and soil organic carbon (SOC) differed between arid and humid grasslands. Light and severe grazing had negative effects while moderate grazing had no effect on the plant Shannon diversity index in arid areas. In humid areas, light and heavy grazing intensities had no effect on plant diversity, while moderate grazing increased plant species richness and the Shannon-Wiener diversity index. In humid areas, light and moderate grazing did not affect SOC, while severe grazing decreased SOC. We concluded that moderate grazing could maintain and improve plant diversity in both arid and humid grasslands. (c) 2025 The Society for Range Management. Published by Elsevier Inc. All rights are reserved, including those for text and data mining, AI training, and similar technologies.

This study examined the effects of supplemental feeding on the weight and meat quality of grazing yaks on the Tibetan Plateau. Thirty male yaks (2.5-3 years old) with similar characteristics were randomly assigned to two groups: the traditional grazing group (G) and the supplemental feeding group (SF). The SF group received 1.5 kg of supplemental feed daily. After 120 days, slaughter performance and meat quality were compared. The results showed that the SF group had significantly higher live weight (137.2 kg vs 175.3 kg, P < 0.001) , carcass weight (63.6 kg vs 89.5 kg, P < 0.001) , and net meat yield (34.0 % vs 40.2 %, P < 0.001) compared to the G group. Moreover, the SF group exhibited lower cooking loss, drip loss, and shear force, indicating improved meat quality (P < 0.05) . Amino acid analysis revealed that the SF group had higher total amino acids (TAA, 13.25 g/100 g vs 14.14 g/100 g, P < 0.001) and essential amino acids (EAA, 5.19 g/100 g vs 6.03 g/100 g, P > 0.05) content, the ratios of EAA/TAA and EAA/NEAA increased by 4 % and 10 %, respectively. Additionally, compared to the G group, the SF group had lower saturated fatty acids (SFA, 43.25 vs 39.22, P < 0.001) and higher polyunsaturated fatty acids (PUFA 11.49 % vs 13.74 %, P < 0.001), particularly omega-3 fatty acids (2.81 % vs 5.31 %, P < 0.001), with a lower n-6/n-3 (2.88 % vs 1.44, P < 0.001) ratio. Principal component analysis (PCA) and partial least squares discriminant analysis (PLS-DA) confirmed the effects of supplementation on amino acids and fatty acids. In conclusion, supplemental feeding significantly improved yak growth and meat quality, particularly in amino acid and fatty acid composition, providing valuable insights for grazing management on the Tibetan Plateau.

Weed invasion, a prevalent consequence of global grassland degradation, necessitates an ecological understanding of the weed community to improve grassland ecosystem management and restoration. In this study we questioned which environmental factors are closely related to grassland weed distribution and what are the changes in grassland biodiversity and ecosystem function caused by grassland weed species? We selected a typical weed infested geographical unit of alpine grassland of 300,000 km2 to respond to these questions. Hierarchical cluster analysis delineated eight distinct weed community archetypes, each characterized by its unique species composition and community attributes. Climate, particularly precipitation, and soil properties, such as pH and moisture content, emerged as pivotal factors mediating the spatial distribution of weed communities. The alpha- and beta-scale diversities revealed disparities in species composition, functional traits, and phylogenetic diversities among weed communities. Environmental factors influenced ecosystem multifunctionality (EMF) through their effects on species, functional traits, and phylogenetic diversities. Environmental factors explained 48.5 % of the variance in EMF, but had an overall negative effect, while, biodiversity variables explained 51.5 % of the variance in EMF, and had an overall positive impact. Functional diversity exhibited a positive influence on EMF, whereas species and phylogenetic diversity exhibited mixed effects. The findings indicate that grassland weed communities alter species compositions and reduce EMF, with impacts from climatic and soil factors. These changes underscore the importance of understanding the complex interplay between environmental factors and biodiversity in managing degraded grasslands. In conclusion, our study provides important insights into the dynamics of weed communities that are essential for developing effective management strategies to mitigate the adverse effects of weed invasion in alpine grassland.

Wetland is the core functional system of the global alpine region. However, with the development of the social economy in the past few decades, the alpine wetland ecosystem has suffered serious shrinkage, drying, degradation and landscape fragmentation. The decoupling of alpine development from the degradation of wetland ecosystem under global ecological protection would be an important basis for the future planning of regional sustainable development. However, little information is available on how this can be achieved. To fill this gap, we selected Maqu County, a typical alpine wetland region in the Qinghai-Tibetan Plateau of China, to analyze the relationship between regional development and wetland ecosystem change in the past 35 years. We examined land use change, landscape pattern, socio-economic development, and a decoupling model. The results revealed that the region underwent a transformation characterized mainly by the conversion of “peatlands to marsh meadows to alpine grasslands.” Peatland decreased by 31.7 %, while desertified lands increased by 78.6 %. Fragmentation of the landscape and wetlands was alleviated during the period from 2000 to 2005; however, the overall trend of fragmentation remained pronounced. A fluctuating decoupling relationship between regional development and landscape fragmentation emerged. Livestock numbers exerted negative effects on landscape stability, especially on wetlands, which indicates that regions reliant on wetland grazing ecosystems for livelihoods are particularly sensitive to grazing activities. We propose a “water-grass-livestock balance” policy centered around water resources that emphasizes the importance of wetland water resource management.

Introduction:Whole-plant corn silage (WPCS) is an important roughage source in ruminant nutrition, and its nutritional value can vary significantly with corn variety. Understanding how different WPCS varieties influence gastrointestinal microbiota and metabolic profiles is essential for optimizing feed efficiency and animal health. Methods:This study examined the effects of three corn varieties (2 introduced - Tunyu 168: TY; Yu silage 23: YQZ, and 1 local Longsheng 1: LS) in WPCS on gastrointestinal bacteria and metabolites in lambs. Thirty 4-month-old female Hu lambs (19.6 ± 0.26 kg) were assigned randomly to three groups (n = 10 per groups). After 90 days, 6 random lambs from each group were slaughtered, and contents from the rumen, ileum and cecum were collected. Results:The LS silage had the highest crude protein (CP) content, the TY silage had the lowest neutral detergent fiber (NDF) content, and the YQZ silage had the highest ammonia nitrogen (NH3-N) content. Dry matter intake (DMI) was greater in lambs fed the YQZ and TY silages than the LS silage, while average daily gain (ADG) was greater in lambs fed the TY silage than the YQZ and LS silages. The greatest concentration of total volatile fatty acids (TVFAs) in the rumen was measured in lambs fed the YQZ silage, and in the ileum and cecum was measured in lambs fed the TY silage. Lambs fed the YQZ silage increased the relative abundances of bacteria that degrade carbohydrates and synthesize volatile fatty acids (VFAs) in the gastrointestinal tract, and decreased the relative abundances of pathogenic bacteria in the rumen; while lambs fed the TY silage increased the relative abundances of bacteria in the cecum that degrade carbohydrate, protein and starch, and decreased the relative abundances of pathogenic bacteria in the rumen. The pathways of nicotinate and nicotinamide metabolism and folate biosynthesis were upgraded with the TY silage; whereas, pentose phosphate metabolism, histidine metabolism and folate biosynthesis were upgraded with the YQZ silage. Conclusion:These findings suggests that the YQZ and TY silages mediate rumen fermentation by altering rumen bacterial populations and metabolic activities, thereby maintaining rumen health and improving lamb growth performance. Lambs fed the TY silage had the greatest ADG and best feed conversion ratio (FCR: DMI/ADG), but the YQZ silage may have greater potential in sheep as it mediates a wider range of metabolic pathways.

Background Yak (Poephagus grunniens) production on the Qinghai-Tibet Plateau is influenced heavily by the quality of the natural forage, which can vary significantly in both quality and quantity. Therefore, timely and accurate monitoring of forage variables is essential for optimizing livestock production in this region. Methods This study investigated the use of near-infrared spectroscopy (NIRS) as a tool for estimating the composition and quality of natural forage. A total of 301 natural forage samples were collected, and their spectral data were acquired using NIRS. Conventional methods were used to measure the forage composition, and predictive models were developed based on the spectral data. Results Our findings indicate that NIRS can accurately predict the contents of crude protein, acid detergent fiber, and neutral detergent fiber. However, it demonstrated less accuracy in predicting dry matter digestibility, gross energy yield, and methane production. Conclusions The application of NIRS for assessing the nutritional composition of forages on the Qinghai-Tibet Plateau is a key advancement for the livestock industry. Understanding forage nutrition enables informed feeding strategies and improvement of livestock production. Future research should refine predictive models to ensure sustainable forage management and enhance livestock productivity in this unique ecological environment.

ABSTRACTThe conversion of shrubland to grassland alters primarily the vegetation, but the impact of this conversion on the carbon budget and carbon management in arid and alpine regions remains poorly understood. To fill this research gap, we compared the effects of shrubland‐to‐grassland conversion, which has been ongoing for at least a decade, on soil organic carbon (SOC) between arid and alpine regions, and examined the mechanisms involved. Shrubland converted to grassland led to a 470% increase in SOC in arid regions; whereas, it led to a 41.4% decrease in SOC in alpine regions. In the conversion to grassland in arid regions, there was a shift in plant species from low‐ to high‐carbon plants, which enhanced carbon input into the soil and facilitated faster decomposition, resulting in an increase in SOC. However, in the conversion to grassland in alpine regions, an opposite trend occurred, resulting in a decrease in SOC. The increase in SOC in arid regions occurred in the late conversion stage; whereas, the decrease in SOC in alpine regions occurred in the early conversion stage. The soil nitrogen to phosphorus ratio (N:P) and the heavy fraction organic carbon (HFOC) were identified as the most important drivers of SOC in arid and alpine regions, respectively, while ecological stoichiometry was the key factor in SOC dynamics. This study provides important insights in SOC dynamics in the conversion of shrubland to grassland. The conversion of shrublands shoud take into account climatic factors, particularly in alpine regions, where shrub removal should be minimized to reduce carbon loss.