In alpine grasslands, nitrogen limitation constrains plant growth, and nitrogen fertilization is a common strategy for rehabilitating degraded lands. However, the effects of different nitrogen types, levels, and durations on plant diversity and ecosystem functionality remain unclear. This study investigates slightly degraded alpine grasslands in the Three Rivers Source Region of the Qinghai-Tibet Plateau. We applied ammonium sulfate, potassium nitrate, and urea at varying concentrations (20 g m−2, 10 g m−2, and 0 g m−2) and assessed plant biodiversity, biomass, and multifunctionality. Under long-term nitrogen addition, different nitrogen types influenced species loss and gain rates, thereby affecting species richness; increasing nitrogen levels elevated species loss rates, while ecosystem multifunctionality remained unaffected by environmental constraints. In contrast, under short-term nitrogen addition, nitrogen type primarily influenced species gain rates, which altered species richness and, in turn, ecosystem multifunctionality; nitrogen levels affected both species loss and gain rates, jointly shaping richness and multifunctionality. Overall, short-term nitrogen addition significantly increased species diversity and biomass, whereas long-term addition reduced diversity without affecting multifunctionality. These findings underscore the contrasting impacts of short- and long-term nitrogen inputs and the combined regulatory roles of nitrogen type, addition level, and application duration in the ecological restoration of degraded alpine grasslands.

Grazing exclusion through fencing is widely used for vegetation restoration in degraded alpine meadows. However, the dynamic responses of plant communities to grazing exclusion remain poorly understood, especially from an integrated perspective of species diversity, niches, and interspecific associations. In this study, we investigated four proximate alpine meadows on the Tibetan Plateau with different fencing durations (0, 2, 6 and 12 years). We assessed the responses of plant diversity, niche characteristics, and interspecific associations to fencing duration, along with relationships among these dimensions. The results showed a unimodal response of plant diversity to fencing duration, with the Patrick richness index varying in coordination with niche and interspecific association metrics. After 2 years of fencing, the community niche breadth expanded, accompanied by increased niche overlap and Ochiai association index among major species. By 6 years of fencing, the niche breadth shifted toward lower values, and niche overlap of major species decreased significantly, with the proportion of species pairs with high overlap and high association reduced by 21.95% and 25.93%, respectively. After 12 years of fencing, niche overlap rebounded significantly, and the proportion of species pairs with high niche overlap and high association increased by 18.79% and 16.84%, respectively. Our findings support identifying 6 years of fencing as a critical intervention point. At this stage, the community achieves a dynamic balance between competition and coexistence through niche differentiation, maintaining high species diversity. We suggest moderate disturbance should be implemented in alpine meadows thereafter to prevent retrogressive succession. This study analyzed the effects of fencing duration (0, 2, 6 and 12 years) on plant community dynamics in alpine meadows across multiple dimensions, including plant diversity, niches, and interspecific associations. The results indicated that 6 years of fencing serves as a critical intervention point for vegetation recovery, where the community achieves a dynamic balance between competition and coexistence through niche differentiation, thereby maintaining high species diversity. (sic)(sic): (sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic).(sic)(sic),(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic).(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic),(sic)(sic)(sic)(sic)(sic)(sic)(sic),(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(0,2,6,12(sic))(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic).(sic)(sic)(sic)(sic),(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic),Patrick(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic).(sic)(sic)(sic)(sic)(sic)(sic)(sic),(sic)(sic)2(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic),(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)Ochiai(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic);(sic)(sic)6(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic),(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)21.95%(sic)25.93%;(sic)(sic)12(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)18.79%(sic)16.84%.(sic)(sic)(sic)(sic)(sic)(sic),(sic)(sic)6(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic),(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic),(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic).(sic)(sic),(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)6(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic).

Alpine grasslands on the Tibetan Plateau constitute a pivotal component of the global carbon cycle. As the dominant CO₂ flux pathway, soil respiration demonstrates marked sensitivity to both climate warming and anthropogenic disturbances. Based on a long-term experiment combining warming (open-top chambers) and mowing (annual clipping), we systematically monitored soil respiration rates, concurrently with soil temperature and moisture, plant community traits, and soil nutrient, to elucidate the responses patterns of alpine meadow soil respiration to warming and mowing and identify their dominant drivers. Soil respiration was significantly affected by the main effects of warming and mowing (P < 0.05) and was strongly correlated with soil temperature and moisture. Q₁₀ decreased by 5.04

Alpine grasslands are increasingly threatened by gravelization, a land degradation process characterized by surface gravel accumulation and vegetation loss, particularly under intensified climate change and anthropogenic disturbance. Despite its prevalence, we lack a comprehensive understanding of how gravel cover affects plant-soil interactions and overall ecosystem functioning. In this study, we investigated how varying levels of gravel cover affect plant community structure, soil physicochemical properties, and ecosystem functions in a typical alpine meadow of the Qinghai-Tibetan Plateau, and assessed the nonlinear responses of aboveground ecosystem function index (AEMF) and ecosystem multifunctionality (EMF) to increasing gravel coverage by generalized additive models (GAMs). Our results revealed that gravelization led to a marked decline in plant species richness, functional group composition, and biomass, especially belowground. Soil water content, nutrient availability, and porosity significantly decreased, while bulk density increased with gravel cover. Both AEMF and the belowground ecosystem function index (BEMF) declined significantly, with BEMF exhibiting a more sensitive response. PiecewiseSEM analysis indicated that gravel cover influenced EMF through both direct and indirect pathways, with soil nutrients and plant diversity as key mediators. A critical threshold was identified at 22% gravel coverage, EMF declined sharply. These findings demonstrate that alpine gravelization substantially impairs EMF through vegetation suppression and soil degradation. Our study provides empirical evidence for threshold-based management and highlights the importance of maintaining plant-soil integrity to safeguard ecosystem functions. The identification of a 22% gravel cover threshold further provides a quantitative earlywarning indicator for conservation and restoration planning in alpine grasslands, with broader implications for ecosystem resilience under climate change and land-use intensification.

The high-altitude desert ecosystem is fragile, and planting Caragana korshinskii is a key measure for ecological restoration, effectively improving soil quality, windbreak and sand fixation, and water conservation. However, how the establishment of plantations affects soil microbial community-mediated multifunctional regulation remains unclear. This study investigated the effects of soil and rhizosphere microbial community characteristics on soil multifunctionality across six planting years (0a, 5a, 15a, 25a, 35a, 50a) in alpine sandy regions. The results demonstrated significantly higher soil multifunctionality in the 35a and 50a compared to CK and 5a. The linear mixed-effects model revealed a significant positive correlation between soil bacterial OTUs richness and soil multifunctionality (p < 0.05), whereas both the Shannon diversity index and Pielou's evenness index exhibited significant negative relationships as well as soil multifunctionality (p < 0.05). Notably, both soil fungal OTUs richness and Chao1 were significantly positively correlated with soil multifunctionality (p < 0.001). Additionally, soil bacterial phyla (Bdellovibrionota and MBNT15), rhizosphere bacterial (Bdellovibrionota and Nitrospirota), and soil factors (pH and soil bulk density) were significantly negatively correlated with soil multifunctionality (p < 0.05). Structural equation modeling indicated that soil factors had a direct negative impact on soil multifunctionality (p < 0.01), followed by the composition of the rhizosphere bacterial community. Our study demonstrated that the responses of soil factors and rhizosphere microbial community composition to Caragana korshinskii artificial plantations establishment were crucial for maintaining soil multifunctionality in alpine sandy regions. We propose that enhanced research into the rhizosphere microenvironment could provide critical insights for establishing systematic approaches to desertification prevention and control.

Due to the sensitivity of alpine meadow ecosystems in the Qinghai-Tibet Plateau to climate change and human activities, dominant plants are gradually being replaced, potentially triggering ecosystem shifts and affecting soil organic carbon (SOC) sequestration. We conducted a three-year dominant plant removal experiment to assess impacts on SOC and related ecological attributes. The results showed a significant increase in SOC across all removal treatments, with the greatest increase following the loss of the dominant species. This increase was enhanced by changes in soil moisture and nitrogen, and was also partly attributed to the presence of remaining plant species. On the contrary, SOC accumulation was less responsive to soil moisture and nutrients under the dominant functional group or total removal, indicating that more severe disturbances reduce the supporting factors of SOC. Metal ions also positively influenced SOC following the loss of the dominant plant group. In particular, this study focused on shallow soil layers (0-10 cm), where SOC gains raise concerns about long-term stability. Correlation analyses and structural equation model revealed that, after the removal of the dominant species, the remaining species maintained the coupling between ecological attributes, preserving ecosystem functioning. However, the removal of dominant functional groups completely disrupted the connections between ecological attributes, reducing the complexity of SOC regulation and key mediating effects. Therefore, prioritizing the restoration of dominant species groups and functional groups is essential for maintaining ecosystem interactions and promoting effective recovery in meadow restoration.

Climate change and intensified human activities have led to plant degradation and land desertification in desert areas, which seriously threaten ecological security. The establishment of the Caragana korshinskii plantation is considered to be one of the important means to improve the ecological environment in thealpine sandy region . This study focuses on Caragana korshinskii plantation in the alpine sandy region of the Qinghai–Tibet Plateau. Adopting a space-for-time substitution approach, six restoration chrono sequences were selected: 0 years, 5 years, 15 years, 25 years, 35 years, and 50 years. By investigating the variations in vegetation community composition and soil properties, we aim to elucidate the plant and soil system interactions under different restoration durations. The findings will clarify the stability evolution patterns of Caragana korshinskii plantation during desertification control and contribute to promoting green development strategies. The main conclusions of this study are as follows: With the passage of planting time, the plant biomass and species diversity of the Caragana korshinskii plantation community showed a trend of first increasing and then decreasing, reaching their peak in 25~35 years. Soil water content exhibited fluctuating trends, while soil organic matter showed progressive accumulation, demonstrating that Caragana korshinskii plantations effectively improved soil fertility. Community stability reaches its maximum (4.98) at 25 years. In summary, the Caragana korshinskii plantation are in an early stage of ecological secondary succession, with plant communities developing from simple to complex structures and gradually approaching, though not yet achieving a stable state.

Soil animals are abundant in soil ecosystems and are sensitive to changes in the soil environment. They play a critical role in the evaluation of soil health under different field management conditions. In this study, a metaanalysis was conducted to examine the effects of biochar addition on different soil animals under different treatments and experimental conditions. The results indicated that the addition of biochar increased the abundance of soil animals (E++ = 0.027) and changed their community structure. Biochar promoted the abundance of soil nematodes (E++ = 0.124) while suppressing that of soil arthropods (E++ = -0.101). The effect of biochar on soil animals was contingent upon both soil properties and the characteristics of the biochar used. Moreover, biochar addition had a positive effect on the abundance of omnivorous-predatory nematodes (OPs) under the conditions of our study. Structural equation modeling (SEM) revealed that biochar affected soil animal abundance through both direct and indirect pathways, with the most significant pathways being those mediated by soil organic carbon (SOC) and soil pH. The amount and duration of biochar addition had different effects on the abundance of different nematode species, ultimately altering the structure of the soil microfood web. This negatively affected the establishment of a stable and healthy soil ecosystem.

Long-term chemical fertilizer use poses sustainability challenges for achieving optimal crop yields and may even diminish yields and fertilizer use efficiency. Sustainable and environmentally friendly agricultural practices must address these challenges by reducing fertilizer application. Biochar emerges as a promising solution, with significant potential for enhancing soil fertility and crop yields. However, its efficacy in sustaining or increasing crop yields under reduced nitrogen (N) fertilizer application remains unclear. This three-year summer maize field study (2019-2021) aimed to elucidate the impact of biochar application on crop productivity, soil characteristics, and economic benefits under varying N fertilizer regimes. Four biochar application rates (0, 8, 16, and 24 t ha- 1) were evaluated alongside three N fertilizer rates: conventional N application (200 kg N ha- 1), 20 % reduction in N application (160 kg N ha- 1), and 40 % reduction in N application (120 kg N ha- 1). Biochar was incorporated once at the start of the experiment, while N fertilizer was applied annually. The comprehensive analysis of the three-year data revealed consistent improvements in maize growth, N uptake, grain yield, and economic returns with biochar, even amidst N fertilizer reductions. While the initial year displayed indistinct biochar effects on maize productivity, its impact was more pronounced in the second year than third year. Path analysis underscored the pivotal role of increased soil organic carbon (SOC), total N content, and cation exchange capacity in enhancing maize yield and its components. Moreover, combinations of 40 % N fertilizer reduction with 16 t ha-1 biochar maintained higher maize yields in 2020 and 2021, suggesting the suitability of biochar rates for sustained efficacy over 2-3 years. On average, maize grain yields increased by 8.5-18.4 % with biochar addition from 2019 to 2021, while economic benefits increased by 15.1-18.4 % in 2020 and 2021. These findings highlight the enduring effects of biochar on crop productivity over at least three years, indicating its potential to consistently enhance maize yield and net income while promoting sustainable agricultural practices.

The makeup of soil microbial communities may serve as a crucial predictor of the alpine grassland ecosystem. Climate change and human disturbance have resulted in intensified ecosystem degradation, such as grassland rocky desertification, which may modify the structures and composition of the microorganisms. However, little is known about the effects of rocky desertification on soil microbial communities of soil. Here, we investigated five different layers of rocky desertification grassland in the Qinghai-Tibet Plateau, including nil rock desertification (NRD); potential rocky desertification (PRD); light rocky desertification (LRD); moderate rocky desertification (MRD); and severe rocky desertification (SRD), we compared soil bacterial community with soil physiochemical properties in different rocky desertification conditions. The result showed that rocky desertification significantly altered the physiochemical properties of the soil but did not significantly affect the bacterial community microbial abundance and diversity. At the same time as rocky desertification increased, soil organic carbon (SOC), total nitrogen (TN), alkali hydrolyzable nitrogen (AN), available phosphorus (AP), and available potassium (AK) decreased significantly, while soil pH, total phosphorus (TP); and total potassium (TK) increased. Redundancy analysis revealed that pH, AK, TP, and SOC are key factors influencing soil bacterial communities. Our finding provides basic information and scientific reference for the restoration of the rocky desertification of alpine grasslands.

Context. Modern species coexistence patterns are known to affect the stability of plant communities; however, the ways in which these patterns influence community stability across different slope aspects and slopes remain unclear. Objectives. We assess the average fitness difference (AFD) and niche difference (ND) within the of modern species coexistence framework, focusing on how these patterns influence community primary productivity stability (PS) and species stability (SS). Methods. We conduct community surveys at different slopes in Maqin County, Qinghai Province, China, in different slope directions. The AFD and ND are measured by community characteristics and lineage diversity, and the stability of communities is evaluated by spatial differences. Results. There was no significant variation in AFD across different slope aspects; however, ND significantly differed, with the northern and western slopes having the highest and lowest values, respectively. PS did not significantly differ across slope aspects; nevertheless, SS significantly differed, with the western and northern slopes having the highest values and the eastern slopes having the lowest. No significant differences were found in species coexistence patterns or community stability across slope gradients. Variance partitioning analysis indicated that only western slope ND contributed to the regulation of community stability (PS and SS). Conclusions. Overall, the slope aspect of alpine meadows influenced the ND in species coexistence patterns, and ND exhibited aspect-dependent regulation of community stability. These findings provide scientific evidence informing the conservation of species diversity and sustainability in alpine meadow ecosystems across various terrains.

Stable bacterial communities are essential for maintaining soil functions. However, the role of abundant and rare bacterial taxa in maintaining bacterial community stability remains controversial. To explore the relationship between abundant and rare taxa and bacterial community stability, we used high-throughput sequencing technology and molecular ecological networks to characterize the distribution of abundant and rare bacterial taxa under different nitrogen (N) fertilization rates (0, 150, 200, and 250 kg N hm-2). Our findings revealed that rare taxa had much higher Simpson's diversity index values than abundant taxa. Moreover, rare taxa Simpson's diversity decreased with increasing N application, while bacterial community differences (Bray-Curtis distance dissimilarity) increased (i.e., bacterial community stability decreased with increasing N application). The network topology showed that rare sub-communities had higher modularity and a greater proportion of positive links than abundant taxa. The rare bacterial Simpson's diversity was significantly and negatively correlated with bacterial community differences, no correlation occurred between abundant bacterial Simpson's diversity and bacterial community differences. This study underscores the importance of rare species in maintaining bacterial community stability. Consequently, when optimizing agricultural management practices to ensure the stability of bacterial communities and soil functions, it is crucial not only to concentrate consider the roles of abundant species involved in nutrient cycling but also to give greater consideration to the role of rare taxa.

Nitrogen (N) addition not only promotes the restoration of degraded grasslands, but also threatens ecosystem functioning through the loss of species richness. Thus, a deep understanding of the effect of N addition on the richness of key organisms in restored grasslands is critical to sustainably restoring degraded grasslands. We conducted a 4-year N addition experiment to investigate the response of both plant and arbuscular mycorrhizal (AM) fungal richness to the combined addition of ammonium (Am) and nitrate (Ni) in a revegetated grassland rehabilitated (with a focus on restoration) on the Qinghai-Tibet Plateau. Both nitrogen forms were added at three levels: 0, 10, and 20 g N m- 2 year- 1. By itself, Ni addition of 20 g N m- 2 year- 1 (Ni20) reduced both plant and AM fungal richness, while Am addition of 20 g N m- 2 year-1(Am20) had no significant effect on them. However, when Ni and Am were combined, only Ni20 plus Am20 among all combinations reduced both plant and AM fungal richness. Both soil nitrate-N and plant species richness jointly drove changes in AM fungal richness, but plant species richness was the main factor affecting AM fungal richness under N addition. Our results suggest that minimizing the loss of AM fungi caused by plant species loss resulting from N addition is a key means to sustainably restore degraded grasslands.

Climate warming and human disturbance are supposed to have significantly impacted the alpine grasslands. However, it is still unclear how human activity affects the community composition and niche characteristics in response to warming. We conducted a two-factorial experiment in an alpine meadow, and set up four treatments: warming, mowing, warming with mowing, and control. Based on the investigation of community composition and niche characteristics, we evaluated the impacts of soil carbon, nitrogen, and phosphorus on species niche overlap. The results showed that mowing significantly increased species richness of Grass, Sedge, Forbs and the importance value of Sedge compared to warming (P < 0.05). The niche breadth of species (>50 %) was reduced by warming, but increased under mowing. The niche overlap mainly occurred between Grass and Forbs in warming, while it was evenly distributed among species after mowing, which alleviated the negative effects of warming on interspecific competitiveness. Warming increased the number of species pairs with a niche overlap value >0.9 by 24.15 %, while warming with mowing decreased it by 2.7 %. The number of species pairs with niche overlap was significantly correlated with soil total nitrogen and soil available nitrogen (P < 0.05). In particular, the species pairs with highly competitive showed a greater dependency on soil nitrogen. Our work highlights that moderate utilization and soil nitrogen are two crucial factors influencing the response of community structure in alpine meadows to future climate change. The study provides an important reference for predicting and addressing the impact of global climate change on adaptive management and grassland protection.

Bacteria serve as a holistic indicator of soil fertility by incorporating both biotic and abiotic aspects of past and present ecosystems. However, a research gap still exists in yield prediction models based on simple and reliable bacterial indicators. This study aims to explore whether machine learning, deep learning, and bacterial biomarker communities can be used to accurately predict crop yields. Soil moisture, nutrients, and bacterial community under different irrigation (I0, I1, I2) and fertilization (N0, N1, N2, N3, O1, O2, O3) treatments were measured using soil physicochemical properties analysis method and high-throughput sequencing approach to predict crop yield using Random Forest (RF), Extreme Gradient Boosting (XGBoost), and Back Propagation Neural Network (BPNN) models. RF and XGBoost were superior in modeling yield, with R2 values of 0.813 and 0.818 and RMSE values of 969.420 kg ha–1 and 957.000 kg ha–1, respectively, outperforming BPNN (R2 = 0.541, RMSE = 1,519.680 kg ha–1). Soil organic carbon and bacterial biomarkers are most influential factors on yield with importance of 21.54

Soil bacteria play pivotal roles in agroecosystem functioning. However, the immense diversity of soil bacterial communities masks the effects of some species, such as bacterial biomarkers, on soil nutrient cycling and crop growth. We analyzed biological and chemical soil parameters of five fertilization treatments (CK, LN, CN, HN, LNM: 0, 150, 200, 250 kg N hm(-2), 150 kg N hm(-2) + 15,000 kg hm(-2) sheep manure). The random forest models were used to select bacterial biomarkers and assess the contributions of bacterial biomarkers and overall bacteria to wheat yield. Moreover, we used a partial least squares path modelling to explore the relationship between fertilization, bacterial biomarkers, carbon (C) and nitrogen (N) cycling functions, soil nutrients, and wheat yield. The results showed that bacterial biomarkers are better predictors of wheat yield than overall bacteria, explaining 52.54% and 16.00% of the variation in yield, respectively. Bacterial biomarkers affected wheat production by increasing soil organic carbon, and available nitrogen content. The LNM treatment significantly improved the relative abundance of beneficial biomarkers, such as Sphingomonadales, Xanthomonadaceae, Lysobacter, and Streptomyces, compared to the LN treatment. In addition, the LNM treatment promoted chitinlysis, cellulolysis, xylanolysis, aromatic hydrocarbon degradation, and aerobic ammonia oxidation, relative to the other inorganic N treatments (LN, CN, and HN). Our results emphasize the role of bacterial biomarkers in wheat yield formation, providing new insights into maintaining agricultural productivity by taking advantage of soil bacterial biomarkers.

Most plant‒soil feedback studies have been conducted on the mechanism by which soil directly influences plant growth performance and mostly in indoor pot experiments; however, it is unclear how plant‒soil feedback is influenced by plant, soil and microbial diversity in grassland ecosystems in alpine meadows with high plant diversity. In this study, plant‒soil feedback patterns were investigated by analyzing plant, soil and microbial characteristics across seven gradients in the time series from light degradation to 10-years of recovery, classified into three categories: ecosystem multifunctionality, biotic and abiotic factors, and comparing the strength and magnitude of plant‒soil feedback in alpine meadows of degradation stages and years of recovery. The results showed that the plant-soil feedback relationships in alpine meadows differed significantly in three aspects: ecosystem multifunctionality, biotic and abiotic factors in the degradation stage and recovery years, and under the degradation gradient, ecosystem multifunctionality decreased from 0.34 to −0.99 with the deepening of degradation, biotic factors increased from −0.17 to 0.09, and abiotic factors increased from −0.17 to 0.15, while in the recovery gradient, ecosystem multifunctionality showed a trend of increasing and then decreasing with increasing recovery years, while biotic and abiotic factors showed fluctuating changes. The plant-soil feedback index indicated that the strength and direction of plant-soil interactions during degradation and recovery were different, and the positive feedback effect was 0.34 and 0.38 in the early stage of degradation and recovery, respectively, which were greater than the negative feedback effect. With the deepening of degradation, the negative feedback effect became more and more obvious, and at the stage of extreme degradation, the negative feedback effect reached −0.99, which was much larger than the positive feedback effect. However, with the increase of the recovery years, the positive feedback effect gradually weakened, and finally all of them were negative feedback effects at 10-years of recovery. This study provides a scientific basis for understanding plant-soil feedback in alpine meadow ecosystems and indicates the direction for the next scientific recovery of alpine meadows.

As a crucial component of the ecosystem, grasslands play a vital job in control the weather, saving water, maintaining biodiversity, and sequestering carbon. Soil nematodes, as integral members of the soil food web, contribute significantly to ecosystem functions. Therefore, a global-scale meta-analysis was conducted to investigate the effects of nutrient addition and environmental factors on grassland soil nematodes in this paper. The findings of this study revealed that, overall, nutrient addition in grasslands increased the abundance of total nematodes, but it also impacted the structure of nematode communities. Moreover, the study highlighted that nematodes abundance was significantly increased under the N-P combined addition, and both nutrient additions in the meadow grassland. Through the use of a structural equation model (SEM), it was determined that environmental factors had a significant negative impact on nematode abundance. Conversely, nutrient addition had a significant positive effect, with the greatest impact observed on omnivorous-predatory nematodes (OP) (λ=0.86). The combined N-P effectively mitigated the negative effects of environmental factors on soil nematodes. Furthermore, this effect was also observed in other nutrient additions, with organic fertilizer having the greatest impact, followed by combined N-P, N, and P. In conclusion, the abundance of nematodes in grasslands is influenced by both fertilizer type and environmental factors. This emphasize the importance of considering nutrient management strategies that take into description both environmental conditions and the specific needs of soil nematodes.

Grassland resources occupy an important place in the national economy. However, grasslands in alpine regions of China are severely degraded, and the effects of land-use types on species composition, soil nutrients, and ecosystem multifunctionality of degraded alpine grasslands are less certain. To ascertain the effects of main land-use types (no-tillage reseeding and fertilization) on species diversity and ecosystem multifunctionality in alpine grasslands, we investigated the changes in these factors by subjecting specified areas. Using a standardized field survey, we measured the cover, richness, and evenness of plants. At each site, we measured microbial diversity and twelve soil variables critical for maintaining ecosystem multifunctionality in alpine grasslands. The results showed that: (1) the Margalef, Shannon–Wiener, and Simpson indices of plant community, and fungal diversity indices increased significantly in no-tillage reseeding and fertilization; (2) at the phyla level, the relative abundances of Basidiomycota, Olpidiomycota, and Proteobacteria increased significantly in no-tillage reseeding and fertilization, as well as, at the genus level, those of Coniochaeta, Solirubrobacter, Pseudonocardia, and Microvirga; (3) the soil physicochemical properties (except the C:N of soil) increased significantly in no-tillage reseeding and fertilization; (4) correlation analysis showed that species diversity was mainly correlated with soil nutrients in control check, while it was mainly correlated with soil physical properties in no-tillage reseeding and fertilization; (5) linear regression analysis showed significant positive relationships between Margalef, Shannon–Wiener, and Simpson indices of plant community and ecosystem multifunctionality. In addition, ecosystem multifunctionality was positively related to Pielou, Shannon–Wiener, and Simpson indices of the fungal community and it was positively related to Pielou and Shannon–Wiener indices of bacterial community. These observations indicated that no-tillage reseeding and fertilization of degraded alpine grasslands had the potential to improve ecosystem functions in many ways.