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Aims Grassland ecosystem has various values of ecological service, including carbon sequestration, sand fixation, and maintaining biodiversity. However, some grassland is currently facing serious problems of degradation. To provide scientific theoretical support for the practice of natural grassland vegetation restoration, it is necessary to clearly understand the limiting factors for vegetation restoration in degraded grasslands. In this study, we explored nutrient limiting factors for vegetation restoration under different degradation stages in typical steppe of Nei Mongol. Methods Plant and soil samples were collected during August in 2021–2022, from 13 sampling sites (each site includes 4 plant communities under different degradation stages: non-degradation, light degradation, moderate degradation and heavy degradation) in typical steppe on the Nei Mongol Plateau. Based on these, we explored the effects of degradations in typical steppe of Nei Mongol on above-ground biomass, coverage, and density of plants community. In addition, soil organic carbon, nitrogen and phosphorus nutrient indicators were also measured. Furthermore, multiple statistical analyses such as least squares regression analysis, redundancy analysis, and multiple linear regression analysis were used to reveal the nutrient limiting factors for vegetation restoration in degraded grasslands. Important findings Plant community above-ground biomass, coverage, and density, as well as the content of soil organic carbon, total nitrogen, and available phosphorus in typical steppe of Nei Mongol, significantly decreased with the intensification of degradation. Under the overall degradation sequence and adjacent degradation succession stages, soil nitrogen content was the most influential factor on the variations of plant properties, while soil phosphorus content marginally affected the overall degradation sequence. These results indicate that the availability of soil nitrogen content is the most important nutrient limiting factor for vegetation restoration in degraded grasslands in this area, which suggests that soil nitrogen fertilizer management should be concerned in the future restoration work of degraded grasslands.

Abstract Aims Soil extracellular enzymes play a crucial role in decomposing soil organic matter and cycling nutrients in the ecosystem. They also help to identify microbial resource limitations and soil nutrient availability. The aim of this study is to determine how grazing, especially overgrazing which can lead to grassland degradation, affects the activities of these enzymes and the nutrient limitation characteristics of typical grasslands in Inner Mongolia. Methods To address the above concerns, we conducted grazing experiments with various stock rates in a temperate grassland in Inner Mongolia and investigated changes in soil extracellular enzyme activities and their stoichiometric ratios under different grazing intensities. We also employed a vector model to identify the soil limiting nutrients. Important findings 1) The results showed that the soil hydrolase activities in the area were low compared with the global soil enzyme library, ranging from 0-300 nmol/g/h. Grazing intensity had a significant impact on the activities of various soil enzymes including α-glucosidase, cellulose hydrolysis, xylosidase, β-d-cellubiosidase, β-1,4-N-acetylamino-glucosidase, glucosaminidase, leucine aminopeptidase, and acid phosphatase. The enzyme activities increased as grazing intensity increased, with the activities peak at the recommended grazing and moderate grazing. 2) The Standardised Major Axis(SMA) regression analysis indicated that there was a significant linear relationship between carbon cycle related enzyme activity, nitrogen cycle related enzyme activity, and phosphorus cycle related enzyme activity. The soil enzyme C:N:P stoichiometric ratio was 1:2.3:1.3, whereas the global result was 1:1:1. 3) The vector model of soil enzyme stoichiometry revealed that the grassland of Inner Mongolia were N and P co-limited, with more intense phosphorus limitation as grazing intensity increased.

Aims The influencing factors on the loss and accumulation of soil organic carbon in degraded grasslands are yet to be clarified. Plant derived lignin phenols is an important composition of soil organic carbon. We aim to explore whether the decomposition of lignin phenols caused by benzene ring opening is an important process of soil organic carbon loss in degraded grasslands. Methods Soil samples were collected in four degradation stages of typical grasslands in Xilingol, Nei Mongol. The content of lignin phenolic and the abundance of the key functional gene for benzene ring opening, catechol-1,2-dioxygenase gene (catA), and product (cis,cis-muconic acid) were measured. Variations of lignin phenols and the abundance of catA gene along the degradation gradient and their correlation with soil organic carbon content were analyzed. Important findings The results showed that 1) compared with non-degraded grasslands, the content of lignin phenols in the soil of light, medium, and severe degraded grasslands decreased significantly, and showed a decreasing trend with increasing degradation. The content of lignin phenols showed the same pattern and was significantly positively correlated with soil organic carbon content. 2) The abundance of catA gene significantly increased in degraded grasslands, and the abundance of its decomposition product cis,cis-muconic acid was significantly higher in moderate and severe degradation than that in light and non-degradation grasslands. 3) The abundance of catA gene was significantly positively correlated with the abundance of cis,cis-muconic acid, while the content of lignin phenols was significantly negatively correlated with the abundance of catA gene. The abundance of catA gene and cis,cis-muconic acid were both significantly negatively correlated with soil organic carbon content. The results showed that, at the sample site scale, the decomposition of lignin phenols caused by benzene ring opening can be a potential mechanism in explaining the changes in soil organic carbon content in degraded typical grasslands in Inner Mongolia. This study is expected to provide a new perspective for the driving mechanism of soil organic carbon loss and accumulation in degraded grasslands, and provide a certain theoretical basis for the restoration of degraded grasslands.

China possesses vast grassland resources, but nearly 70% of these grasslands experiencing varying degrees of degradation due to the dual impacts of climate change and human activities. Identifying characteristic factors which can drive grassland degradation and establishing a rapid diagnostic system is essential for assessing their conditions accurately.This study was conducted in the Hulunbuir meadow steppe of Nei Mongol. The selected sites were classified as non-degraded, lightly degraded, moderately degraded, and heavily degraded. Vegetation and soil indicators were collected. Using the random forests algorithm, degradation indicators were screened and weighted, and an attempt was made to balance the ecosystem service needs of both the government and pastoralists.This study identified ten key factors to represent degradation, including aboveground biomass, proportion of high-quality forage, community height, litter biomass, species richness, leaf dry matter content, leaf thickness, soil density, soil moisture content and soil inorganic nitrogen content. These factors are related to various ecosystem services, including forage supply, erosion control, biodiversity conservation, vegetation resilience and water and nutrient regulation. Using non-degraded sites as a reference, a degradation index (DI) for the meadow steppes of Nei Mongol and delineated the DI ranges for different degradation levels is developed. This study provides data support for the rational selection of indicators in current national and local standards.

Aims Plant-soil nutrient feedback is indispensable for maintaining stability and multifunctionality of terrestrial ecosystems. However, plant-soil mutual feedback relations on carbon (C), nitrogen (N) and phosphorus (P) and the key factors promoting the plant succession during sandy land restoration are still unclear. This study employed ecological stoichiometry theory to explore the plant-soil nutrient feedback relations in sandy land from the perspective of soil microorganisms, and to reveal the limiting factors for ecological restoration of degraded vegetation in sandy land. Methods We selected different landscape types in Hulun Buir sandy land, including mobile dunes, semi- mobile dunes, semi-fixed dunes, fixed dunes, and sandy grassland. The space-for-time substitution ap-proach was used to investigate the characteristics of the C, N, and P stochastic geometries of the plant-soil coordination equilibrium and the key drivers in the restoration process. In addition, a correlation analysis between plant-soil stoichiometry and soil microbial communities was performed to reveal multiple driving mechanisms influencing of soil physicochemical factors, plant communities, and soil microbial communi-ties on plant-soil stoichiometry during plant restoration in degraded sandy areas. Important findings 1) With vegetation restoration in degraded sandy land, soil C, N, and P contents, as well as the ratio of C:P and N:P showed significant increasing trends, Conversely, C, N, and P contents and their stoichiometry in living plants and roots did not show clear trends. These suggest that sandy plant communities are still capable of maintaining their nutrient balance, and that their stoichiometric balance is relatively stable as environmental conditions recover and change. 2) Soil C:P (12.08~38.40) was at a low level, resulting in net soil P mineralization, and microbial decomposition of organic matter was not limited by P, and above-ground plant N:P were all lower than 10, indicating that the growth of vegetation in Hulun Buir Sandy Land was mainly limited by N. 3) Meanwhile, the soil N:P continued to increase, indicating that the supply of soil N gradually increased, while the supply of P gradually decreases, and P perhaps become a limiting element in the later stages of vegetation restoration. 4) During vegetation restoration in the Hulun Buir Sandy Land, soil stoichiometry and pH had direct significant positive effects on plant stoichiometry, while soil microorganisms indirectly affected plant stoichiometry by regulating soil stoichiometry. In addi-tion, the indirect effects of soil moisture, soil texture, and electrical conductivity on soil and plant stoi-chiometry should not be neglected. This study provides a theoretical basis for adaptive management and prediction of ecosystem restoration in degraded sandy soils.

Aims The alpine meadows on the eastern Qingzang Plateau have degraded in some areas due to long-term overgrazing. As a crucial resource for degraded ecosystem restoration, the dynamics of soil seed banks and their role in degraded alpine meadow restoration remain unclear.. Methods We chose four different degradation levels of alpine meadows to construct a degradation sequence/gradient on the eastern Qingzang Plateau, and we investigated the plant community and soil seed bank along the degraded gradient, explored the change of plant community and seed bank on the degradation gradient and analyzed the potential role of seed bank in alpine meadow regeneration and degraded alpine meadow restoration. Important findings The results showed that 1) the species richness and relative abundance of plant community decreased significantly along the degradation gradient, but the species richness of soil seed bank increased first and then decreased, and the seed density decreased significantly along the degraded gradient. 2) The similarity of species composition between the plant community and soil seed bank gradually increased with the degradation gradient, which suggests that the role of soil seed bank in plant community regeneration increased along the degraded gradient. 3) Compared with the plant community, there is a hysteresis response of the soil seed bank to alpine meadow degradation, which can buffer the influence of alpine meadow degradation on the plant community to a certain extent. Our findings indicated that the response of plant community and soil seed bank to degradation is different, and soil seed bank is crucial for the degraded alpine meadow restoration on the Qingzang Plateau. However, the potential role of the seed bank in the degraded alpine meadows restoration will be limited because of the depletion of seed bank resources under the seriously degraded level. These results can provide a scientific basis for the protection, restoration, and management of degraded alpine meadows on the Qingzang Plateau.

Aims The biodiversity-productivity relationship is a prominent research topic within ecology. As results of global environmental changes and human disturbance, plant biodiversity has declined worldwide, thus threatening the provision of multiple ecosystem functions. Grasslands are among the most widespread ecosystems on Earth, but are under severe threat from ongoing degradation, with ~50% of grassland area globally having been degraded to some extent. Grassland degradation substantially alters plant diversity and community composition; however, it remains elusive how these changes link to ecosystem productivity across broad geographic scales. Methods Using a standardized survey from 45 grassland degradation sequences at 15 sites across three grassland types (i.e., alpine steppe, alpine meadow and alpine swamp meadow) on the Tibetan Plateau, we aim to explore changes in plant diversity and functional groups upon grassland degradation and their linkages with aboveground net primary productivity (ANPP). Important findings Across the three grassland types, species richness, Shannon-Weiner index, Simpson index and Pielou evenness index all exhibited a first increase and then decrease pattern as degradation intensified. The coverage of sedge and grass declined, but legume coverage showed no significant changes and forb coverage increased along the degradation gradient. Mixed-effects models showed that degradation-induced change in ANPP was mainly associated with changes in coverage of original dominant species but minimally influenced by plant diversity for all grassland types. These results indicate that the degradation-induced productivity reduction is caused by the decline in dominant species rather than losses of plant diversity. The above findings provide important clues for alpine grassland restoration: restoring dominant species would be an effective approach for boosting ecosystem productivity in degraded grasslands on the Tibetan Plateau. Methods Using a standardized survey from 45 grassland degradation sequences (including non-degradation, slight degradation, moderate degradation and heavy degradation) across 15 sites on the Tibetan Plateau, we aim to explore changes in plant diversity and functional groups upon grassland degradation and their linkages with aboveground net primary productivity (ANPP). Important findings Species richness, Shannon-Weiner index and Simpson index exhibited a first increase and then decrease pattern, while there was an increasing trend of Pielou evenness index as degradation intensified. The coverage of sedge and grass declined, but legume coverage showed no significant changes and forb coverage increased along the degradation gradient. Mixed-effects models showed that changes in ANPP was mainly associated with sedge coverage but minimally influenced by plant diversity across various degradation levels. These results indicate that the degradation-induced productivity reduction is caused by the decline in dominant species rather than losses of plant diversity. The above findings provide important clues for alpine grassland restoration: restoring dominant species would be an effective approach for boosting ecosystem productivity in degraded grasslands on the Tibetan Plateau.

Reseeding is one of the key measures for grassland restoration, and the selection of reseeding species and their combination is crucial for the restoration effect. How to rationally combine multiple species to maximize functional complementarity and ensure community stability and multifunctionality is the key to grassland restoration. Methods Based on this, this study conducted a multi-species combination experiment of native grasses in a typical degraded alpine meadow in Maqu, Gannan, Gansu. Important findings The results showed that multi-species reseeding significantly increased the biomass, coverage and species richness of the grassland. We comprehensively evaluated the indexes of aboveground biomass, species richness and proportion of high-quality forage in grassland after mixed reseeding different species combinations. Eventually, the combinations with better performance were screened out as: combinations based on grass mixtures: Elymus nutans + Festuca sinensis + Poa pratensis + Festuca rubra + Poa crymophila + Puccinellia tenuiflora; combinations based on grass-legume mixes: Elymus nutans + Festuca sinensis + Poa pratensis+ Festuca rubra + Tibetia himalaica + Medicago ruthenica and Elymus nutans + Festuca sinensis + Poa pratensis + Festuca rubra + Tibetia himalaica + Medicago ruthenica + Vicia unijuga + Astragalus laxmannii; combinations based on grass-legume-sedge mixes: Elymus nutans + Festuca sinensis + Poa pratensis + Festuca rubra + Tibetia himalaica + Medicago ruthenica + Vicia unijuga + Astragalus laxmannii + Cyperaceae. These multi-species mixing combinations maintained better community stability and grass production performance during the restoration of alpine degraded meadows in Gannan, which can provide a reference for alpine grassland restoration in similar degraded areas.

Aims Constructing multifunctional group species combination model is crucial for restoring severely degraded alpine grassland. However, the responses of multifunctional group species combination to severely degraded alpine meadows and relationship between plant diversity and ecosystem multifunctionality on the Qingzang Plateau remain unclear. Methods In the study, we focused on the severely degraded alpine meadow at Maqin County in the Sanjiangyuan Nature Reserve, and constructed four species combination models including grass mixture, grass + legume mixture, grass + legume + sedge mixture and grass + legume + forb mixture. The study evaluated the ecosystem multifunctionality under different species combination models by measuring plant diversity, primary productivity, and soil factors. Furthermore, the relationship between plant diversity and ecosystem multifunctionality was analyzed. Important findings The results showed that: (1) Among the four species combination modes, the grass + legume + sedge mixture had the highest species richness and Shannon-Wiener index, whereas there was no significant differences in Simpson index and Pielou index between the multifunctional group species combination models. (2) The biomass increased significantly with the addition of plant functional group numbers, and was the highest in the grass + legume + sedge mixture. (3) Except for pH, conductivity, and available phosphorus, all other indicators increased significantly under the grass + legume + sedge mixture. (4) Ecosystem multifunctionality was the highest under the grass + legume + sedge mixture, and the ecosystem multifunctionality showed decreasing pattern along with the increasing of plant diversity. Our results indicated that the grass + legume + sedge mixture has a significant impact on promoting the recovery of soil nutrients and improving primary productivity in severely degraded alpine meadows. The study provides a multifunctional group species combination reference for the restoration of severely degraded alpine meadows in the Sanjiangyuan region, and are of great significance for promoting the theoretical development of ecological restoration in severely degraded alpine meadows on the Qingzang Plateau.

Aim Seed coating technology is an important measure to improve seedling establishment and growth in extreme habitats, but most of the existing coating technologies are applied to economic crops. In order to address the problems of poor field emergence and difficult establishment of main reseeding grass species on the Qinghai-Tibet Plateau, this study designed different formula seed coatings, aiming to provide technical support for the efficient utilization of native grass species in alpine degraded grasslands on the Qinghai-Tibet Plateau. Methods Different formula seed coatings containing nutrients (N), microbial inoculants (MC), and growth regulators (G) were designed. Indoor pot and field experiments were conducted to evaluate the effects of different seed coating treatments on the seed emergence and growth of three grass species. Important findings The pot experiment results showed that the emergence rates of Elymus nutans and Poa pratensis treated with NMCG were better than those of other formulas, with the emergence rates increasing by 27% and 44% respectively compared with the control (filler coating, CK3). The above-ground biomasses of Elymus nutans treated with NMC were the highest, and the below-ground biomasses of Elymus nutans treated with CK2 were the highest. The above-ground biomasses of Festuca sinensis treated with MC2 were the highest, and the below-ground biomasses of Festuca sinensis treated with NMC were the highest. The above-ground and below-ground biomasses of Poa pratensis treated with NMCG were the highest. The field experiment results showed that after the seeds were reseeded with NMCG, the restored grassland had the highest height, coverage, and above-ground/below-ground biomass. The restoration effects of other formula-coated reseeding were also better than those of bare seed reseeding (CK2) and native grassland (CK1). The seed dressing treatments containing microbial inoculants significantly increased the proportion of high-quality forage grass in the restored grassland.

Aims The serious degradation of grassland ecosystems is restricting China's ecological security and economic development, and this makes it a scientific and technological challenge for pastoral areas to effectively restore degraded grasslands. To date, multiple grazing management and human assisted improvement techniques have been developed, the implementation of these techniques played important roles in grassland restoration, but their ef-fectiveness was constrained for degraded grasslands with severe community structure degradation and severe lack of propagule. Methods In this paper, we introduce a propagule regulation technique which can remove propagule limitation and targetly restore moderately and severely degraded grasslands. This technique includes two key technical aspects, namely, cultivation and transplantation of "propagule island". The cultivation of "propagule island" is planting high-quality forage combining with nutrient management to promote the rapid growth of rhizomes (or lateral buds), i.e., cultivating "propagule island" with rich propagule pool (tiller rhizomes or branching buds). The transplantation of "propagule island" is replenishing the propagule pool to degraded grassland, and restore grassland relied on the cloning growth (or asexual reproduction) of high-quality forage. Important findings The main purpose of this technique is to rapidly restore the community structure and function in degraded grasslands using the advantages of cloning growth (or asexual reproduction) of high-quality forage. According to the technical demonstration in the meadow grassland, the “propagule islands” of Leymus chinensis and Medicago falcata L. had siginificant restoration effects, they increased the community productivities from 214.5g m-2 to 358.7g m-2 and 286.4g m-2, respectively. They also increased the proportions of high-quality forage from 18.4% to 54.7% and 31.5%, respectively. This technique can provide important data and technical supports for the targeted restoration of propagule-restricted grassland.

The restoration of degraded grassland is a bottleneck issue in grassland management and sustainable utilization in China. Soil nutrient deficiency is one of the main limiting factors for restoration of degraded grassland. The essence of soil nutrient regulation is to restore the original dominant species, promote grassland productivity and the ratio of high-quality forage of degraded grasslands while minimize the negative environmental effects caused by nutrient addition. Based on the restoration experiment carried out in Hulun Buir degraded grassland, the soil nutrient deficiency status of degraded grassland, the theory of limiting elements for plant growth and the specificity of nutrient requirements for different plant species, this article proposes soil nutrient regulation technique. The key processes include 6 technical points: soil nutrient regulation based on demand, nitrogen and phosphorus synergy, microelements supplemention, fertilization in early spring, applying deeply into the soil, and strip operation. Soil nutrient regulation technique has broad application prospects in Hulun Buir steppe in northern China. Improving the production and ecological functions of degraded grasslands is of great significance for increasing the income of farmers and herders, ensuring the forage security, and safeguarding ecological security and national unity in northern China.

Aims Leymus chinensis grassland is one of the most representative vegetation types in northern temperate grassland of China. Overgrazing causes great decline in the proportion of L. chinensis biomass to community biomass. Application of organic and inorganic fertilizers can significantly promote the recovery of L. chinensis population, but the underlying mechanisms is still poorly understood. Methods In a degraded L. chinensis grassland in Hulun Buir, the effects of organic and inorganic fertilizers on plant community, L. chinensis populations and individuals were explored with the same amount of nitrogen (10 g·m–2·a–1) and phosphorus (3 g·m–2·a–1) application. Important findings At the plant community level, the application of organic and inorganic fertilizers both consistently and significantly increased above-ground biomass in all three years (2021–2023), with the higher biomass under organic fertilizer application. While the application of organic fertilizer significantly reduced the species richness in the second and third year at community level. At the population level, both organic and inorganic fertilizers significantly increased the aboveground biomass of L. chinensis and its proportion in community-level biomass, with higher values under organic fertilizer application. In the third year, the density of L. chinensis with inorganic and organic fertilizer treatments significantly increased by 1.79 and 8.89 times, respectively. At the individual level, the biomass of L. chinensis with inorganic and organic fertilizer treatments significantly increased by 85.3% and 69.1%, respectively. Variance partition analysis suggested that the population density and individual biomass respectively explained 81.8% and 6.2% of the variation in population biomass of L. chinensis. Our results suggested that the application of organic or inorganic fertilizer can promote the restoration of degraded L. chinensis grassland. The increase in population density rather than individual biomass of L. chinensis is the predominant mechanism for its population recovery.

Declining soil quality is one of the key limiting factor of recovery in moderately degraded alpine meadows. Meanwhile, irrational application of nitrogen and phosphorus fertilizers has a significant negative effect on the biodiversity of the Qingzang Plateau. However, there have been very few studies on the soil quality improvement techniques for moderately degraded alpine meadows on the Qingzang Plateau of systematic research. The objective of this study was the effect of nitrogen and phosphorus fertilizers and microbial fertilizers on soil chemical properties and enzyme activities in moderately degraded alpine meadows.In this study, plant community characteristics, soil physicochemical properties and enzyme activities of different treatments were investigated under the treatment of nitrogen and phosphorus fertilizers with coupled microbial fertilizers in moderately degraded alpine meadows on the Qingzang Plateau.The results showed that both nitrogen and phosphorus fertilizers with microbial fertilizers significantly increased aboveground biomass, and there was a significant interaction (p < 0.05) on the effects of soil nutrient-related indexes, conductivity, and enzyme activities related to CNP cycling. Comprehensively, it can be seen that the application of both nitrogen and phosphorus fertilizers and microbial fertilizers have obvious restoration effects on moderately degraded alpine meadows, microbial fungal fertilizers can be applied to improve the soil multifunctionality, and nitrogen and phosphorus with microbial fertilizers has a better effect than the application of nitrogen and phosphorus fertilizers alone. The best physiological effect is nitrogen addition of 45 kg·hm–2 with phosphorus application of 20 kg·hm–2 with microbial fertilizer application of 225 kg·hm–2. The results of this study provide a scientific basis for promoting the restoration of moderately degraded alpine degraded meadows on the Qingzang Plateau and improving the ecosystem service function.

Aims Most of the grasslands in the Sanjiangyuan area are degraded to different degrees, and planting artificial grassland is an important measure to restore the ecological function of heavily degraded grasslands. Moss crust affects the soil nutrient cycling and the structure of microbial communities, and it is important to investigate the feasibility of moss crust to promote the restoration of degraded grasslands, in order to correctly understand the ecological role of bioconjugate crusts, and to formulate reasonable and effective ecological restoration measures. Methods In this study, four different grass combinations and three types of moss crust inoculation were set up to investigate the effects of moss crust inoculation on the soil microenvironment of artificial grassland, with the “black soil beach” of Sanjiangyuan as the research object. Important findings Moss crusts increased soil organic carbon, available phosphorus, ammonium nitrogen and nitrate nitrogen contents, and the content of fast-acting nutrients in the artificial grassland was significantly higher than that in the “black soil beach”. The top 5 dominant taxa in terms of mean relative abundance at the phylum level for bacteria were Actinobacteria, Proteobacteria, Acidobacteriota, Chloroflex and Firmicutes; and for fungi, the top 5 dominant taxa in terms of mean relative abundance at the phylum level were Ascomycota, Basidiomycota, Mortierellomycota, unclassied_k_Fungi, Olpidiomycota. With the increase of moss crust inoculation, the number of bacterial OTUs decreased and the number of fungal OTUs increased, and the moss crust inoculation did not significantly affect the microbial diversity index; the results of the mixed-effects model indicated that the moss crust had a significant effect on the effective phosphorus, nitrate nitrogen, ammonium nitrogen, and microorganisms affecting their accumulation ; Redundancy analysis shows that the bacterial community structure is susceptible to soil factors; Mantel test results indicated that moss crust A1(700 g·m–2)inoculation had a significant effect on bacterial community composition than fungal community, and effective phosphorus, ammonium nitrogen, nitrate nitrogen were significantly and positively correlated with bacterial community. The above results indicate that moss crust inoculation may affect soil nutrient accumulation and cycling process by changing the microbial community environment, and promote the recovery of ecological function of the artificial grassland in Sanjiangyuan, which provides a theoretical basis for further investigation of moss crust addition to restore the ecological function of the soil of extremely degraded grassland in the future.

Aim The application of growth promoter is an important tool for restoration by human intervention. Therefore, the aim of this paper is to investigate the growth promoting effect of Dry mycelium of Penicillium chrysogenum (DMP), a residue from the industrial production process of penicillin, on the Trifolium repens and Lolium perenne. Methods In this study, we mainly used pot experiment and field experiment to investigate the growth promoting effect of DMP addition on the T. repens and L. perenne. Then we use transcriptome sequencing to determine the Molecular mechanism of DMP promoting forage growth. Important findings The results of this study are as follows. (1) DMP addition can significantly improve their physiological indices and enhanced developmental morphological traits of T. repens and L. perenne. Compared with the positive control of compound fertilizer treatment, the application of 4.50 g DMP per pot under potting condition significantly increased the plant height, tiller number and leaf number of L. perenne, and the application of 2.25 g DMP per pot significantly increased the plant height, branching number and leaf number of T. repens, while 4.50 g/pot of DMP significantly increased the total chlorophyll, crude protein content and crude fat content of L. perenne, and this concentration of DMP treatment also significantly increased the total chlorophyll and crude protein content of T. repens. （2）DMP addition can increase the biomass of L. perenne and T. repens. Under potting conditions, DMP application significantly increased aboveground fresh and dry weights of L. perenne and T. repens compared with the positive control of compound fertiliser treatment. DMP at 15 kg/667 m2 also increased aboveground and belowground dry weight accumulation of L. perenne and T. repens under low temperature and low sunlight field conditions in Zhaotong. （3）Transcriptome sequencing showed that DMP treatment induced the expression of genes related to phytohormone biosynthesis and signal transduction pathways in L. perenne, confirming that DMP promotes forage growth by inducing hormone biosynthesis and signal transduction pathways. This study first demonstrates that DMP can promote the growth of forage, and proposes a new strategy of using DMP as a growth promoter for forage, which provides new ideas for the restoration and sustainable development of degraded grasslands under low temperature and low sunlight conditions.

Abstract Aims Plateau pika (Ochotona curzoniae) is a dominant small herbivorous mammal on the Qinghai-Tibet Plateau, which affects the grassland ecosystem function through feeding, digging and excreting. Eimeria spp., as the main intestinal parasite of plateau pika, has good speciation specificity and is a potential new model for population control of plateau pika. However, the plant change of alpine grassland after Eimeria spp. control of plateau pika is still unclear. Methods In this study, the grassland after Eimeria spp. control of plateau pika and the control grassland were selected, and the plant diversity and network stability of alpine grassland after different treatments were analyzed to explore the effects of Eimeria spp. control of plateau pika on the plant community structure of grassland. Important findings After field placement of Eimeria spp., the active burrow entrance of plateau pika decreased significantly, and the effect of glires control was good. After Eimeria spp. treatment, grassland total coverage, Shannon-Wiener index, Simpson index and β diversity index increased significantly. The results of the mixed-effects model showed that Eimeria spp. treatment had a greater impact on the Simpson index and Pielou evenness index. Increased inter-community correlations and average connectivity and stability in co-occurrence network analyses of plant communities after Eimeria spp. control of plateau pika, and grassland keystone species changed from forbs to gramineae and cyperaceae. The results of this study provide new insights for biodiversity conservation, glires control, and ecosystem adaptive management of alpine grassland on the Qinghai-Tibet Plateau.

Aims Grassland, that dominated by Leymus chinensis, is one of the most important grassland types in northern China, with important ecosystem service functions. However, due to long-term irrational utilization, the nutrient of the ecosystem stays a state that the outputs exceed the inputs, resulting in a widespread degradation of the current Leymus chinensis grassland. The degradation affects its ecological and production functions. Previous studies have shown that the coupling of livestock and poultry can promote the restoration of degraded grasslands. This study aims to clarify the impacts of the coupling of livestock and poultry on L. chinensis individual, population and community. Methods This study compared the differences of the individual traits, population and community characteristics of L. chinensis in livestock and poultry coupled plots (LP), grass mowing plots (GM), and traditional cattle and sheep grazing plots (CS). Important findings The results showed that the soil NO– 3-N content in LP was 2.5 to 3 times that of GM and CS, and the soil available phosphorus content was more than 2 times that of GM and more than 6 times that of CS. The increase in soil nutrients significantly improved individual traits and population characteristics of L. chinensis. The chlorophyll content, specific leaf area, nitrogen content and phosphorus content of L. chinensis leaves in LP were significantly higher than those in GM and CS. The important values of L. chinensis population in LP significantly increased by 29.7% and 173.2% compared to GM and CS in the first year, respectively. The leaf area index of L. chinensis population in LP reached above 3.4, while GM remained around 1.0 and CS remained around 0.2; The aboveground biomass of L. chinensis population in LP increased to (431.5 ± 45.3) g·m–2 in the second year, which was 1.6 times that of GM and 9 times that of CS. The development of the L. chinensis population promoted the positive succession of plant communities, with the plant cover in LP reaching over 90%, significantly higher than GM (around 60%) and CS (approximately 40%). The aboveground biomass of plant community in LP increased to (597.6 ± 61.3) g·m–2 in the second year, close to twice that of GM and 3 times that of CS. Under the utilization of coupling livestock and poultry, chickens fertilize the degraded grassland with manure during the plant growing seasons, which promotes the individual growth and development of L. chinensis and so that increases the important value of L. chinensis population as well as the plant community coverage and aboveground biomass, and thus promotes the degraded L. chinensis grasslands toward near natural recovery. Methods This study compares the differences of the individual traits, population and community characteristics of L. chinensis in livestock and poultry coupled plots (LP), grass mowing plots (GM), and traditional cattle and sheep grazing plots (CS). Important findings The results showed that the soil NO3--N content in LP was 2.5 to 3 times that of GM and CS, and the soil available phosphorus content was more than 2 times that of GM and more than 6 times that of CS. The increase in soil nutrients significantly improved individual traits and population characteristics of L. chinensis. The chlorophyll content, specific leaf area, nitrogen content and phosphorus content of L. chinensis leaves in LP were significantly higher than those in GM and CS. The important values of L. chinensis population in LP significantly increased by 29.7% and 173.2% compared to GM and CS in the first year; The leaf area index of L. chinensis population in LP reached above 3.4, while GM remained around 1.0 and CS remained around 0.2; The aboveground biomass of L. chinensis population in LP increased to 431.5 ± 45.3 g m-2 in the second year, which is 1.6 times that of GM and 9 times that of CS. The development of the L. chinensis population promotes the positive succession of plant communities, with the plant cover in LP reaching over 90%, GM maintaining around 60%, and CS maintaining around 40%; The aboveground biomass of plant community in LP increased to 597.6 ± 61.3 g m-2 in the second year, close to twice that of GM and 3 times that of CS. Chickens fertilize the grassland with chicken manure during the plant growth season when using grassland with the type of coupling livestock and poultry, which reverses soil nutrient deficiency, promotes individual growth and development of L. chinensis, increases the important value of L. chinensis population, increases plant community coverage and aboveground biomass, and promotes near natural recovery of degraded L. chinensis grasslands.