This study was conducted in the temperate steppe of Ningxia Luoshan Nature Reserve. The dominant plant species at different altitudes were selected as research objects： Carex aridula at 2374 m， Stipa grandis at 2132 m and 1823 m， and Stipa breviflora at 1566 m. Xylem water from the dominant plants， precipitation， and soil water from the 0-100 cm layer were collected. The stable hydrogen （δD） and oxygen （δ¹⁸O） isotopic compositions were determined. The MixSIAR mixing model was employed to quantitatively analyze the utilization ratios of plants to potential water sources. The results showed that： （1） Soil water δ¹⁸O exhibited significant spatial heterogeneity， generally decreasing with increasing altitude， with significantly lower isotopic values in soil water at high altitudes compared to low altitudes. （2） The water use patterns of dominant plants at different altitudes showed significant differences during the growing season （June-July）. Carex aridula at high altitude shifted its main water absorption source from the 40-60 cm soil layer （23.8%） in June to the 0–20 cm layer （26.9%） in July. Stipa grandis at mid-altitude changed from absorbing water from all soil layers （0-100 cm） with proportions ranging between 15.9% and 22.3% in June to concentrating water uptake in the 0-40 cm layer in July. Stipa breviflora at low altitude stably utilized water from the 0-20 cm shallow soil layer， with a utilization proportion between 27.8% and 32.4%. This study provides an important scientific basis for understanding the water use strategies of dominant species and the water balance in the Luoshan temperate steppe ecosystem.

To investigate the appropriate nitrogen addition concentration for synergistically restoring productivity and maintaining biodiversity in degraded alpine steppe， this study conducted a randomized block experiment in the northern Xizang alpine steppe （elevation 4634 m）. Six nitrogen addition gradients （0，5，10，15，20， and 25 g·m^-2·a^-1 N） were set under natural conditions and with phosphorus application. Mixed-effect models were used to analyze the effects of nitrogen addition on plant aboveground biomass， community structure， and diversity. The results showed that short-term nitrogen addition significantly increased plant aboveground biomass， with the promoting effect strengthening as nitrogen concentration increased. Simultaneously， nitrogen addition significantly reduced plant diversity， with the inhibitory effect intensifying with higher nitrogen concentrations， accompanied by an increase in the importance value of grasses and a decrease in the importance values of sedges and forbs. Phosphorus application enhanced the positive effect of nitrogen addition on aboveground biomass but did not significantly exacerbate the inhibition of plant diversity. This study reveals that moderate nitrogen addition （10~15 g·m^-2·yr^-1N） with phosphorus application may be an effective restoration measure for degraded alpine steppe， providing a scientific basis for the sustainable management of alpine steppe ecosystem.

In order to study the nitrogen and phosphorus homoeostasis of plant community of desert steppe under different stocking rates， the Stipa breviflora desert steppe in Inner Mongolia was used as the research object. The grazing experiment adopted a completely randomized block design， with a total of 4 levels of stocking rate and 3 repetitions， namely control （CK）， light grazing （LG）， moderate grazing （MG） and heavy grazing （HG） [sheep units·hm^-2·0.5a^-1]. The total nitrogen （TN） and the total phosphorus （TP） in plant community and soil were measured， and than calculated the homeostasis index （H）， the results showed that the interaction between grazing and soil layer had no significant effect on the soil. Grazing attenuated TN and TP homeostatic regulation of the plant community. When the stocking rate was <1.1 or> 3.65， TN homeostasis was weakly homeostatic. The TP homeostasis was enhanced in HG. When the stocking rate was <1.09 or> 2.78， TP homeostasis was weakly homeostatic. The N∶P homeostasis was the strongest in MG， and when the stocking rate ranged from 0.17 to 1.9， the N∶P homeostasis was weakly homeostatic. Overall， when the stocking rate ranged from 0.17 to 1.09， which is a light to moderate grazing level， the grassland ecosystem had homeostatic regulation. The stocking rate has a minimum threshold of 2.37 for H_TN and 1.94 for H_TP， while a maximum threshold of 1.03 exists for H_N∶P.

Grazing is a primary utilization method of grasslands， and determining the appropriate grazing intensity is of crucial for grassland conservation and the sustainable development of animal husbandry. A controlled grazing experiment was conducted during the warm season of 2023 at the 77th Regiment Horse Farm in Zhaosu County， four treatments were set up： no grazing， light grazing （1 horse·hm^-2）， heavy grazing （4 horse·hm^-2）， and extreme grazing （6 horse·hm^-2）， and a randomized block design was adopted. The effects of grazing intensity on pasture carrying capacity were evaluated by monitoring plant community structure， diversity， standing biomass， forage nutritional quality， and by calculating digestible energy （DE） and the grading index 2001 （GI₂₀₀₁）.The results indicated that light grazing maintained relatively a high species diversity， while the no-grazing area exhibited the best forage nutritional quality. The biomass carrying capacity was the highest under heavy grazing [0.73 horse·hm^-2·（122d）^-1]， and the crude protein yield carrying capacity was relatively high under extreme grazing [0.99 horse·hm^-2·（122d）^-1]. However， these conditions were accompanied by the decline of sedges and a surge in forbs， representing an unsustainable short-term phenomenon. The PLS-PM （Partial Least Squares Path Modeling） model showed a direct negative effect of grazing intensity on GI₂₀₀₁ and DE. In conclusion， light grazing （1 horse·hm^-2） is the suitable intensity for the Zhaosu mountain meadow steppe， effectively balancing ecological conservation and the needs for continuous grazing of Yili horses.

Land-use change is a significant factor affecting biodiversity. To explore the effects of different land-use types on insect community structure and diversity in the agro-pastoral ecotone of the Bashang region， a study on insect species composition and community structure was conducted from July to September 2024 in fenced grassland （FG）， grazed grassland （GL）， and cropland （CL） in the Bashang region of Hebei Province. A total of 937 insect individuals were collected， representing 103 species belonging to 45 families and 6 orders. The study revealed that land-use type significantly affected insect community structure and diversity （P<0.05）. Among them， FG had the highest diversity， followed by GL， and CL had the lowest diversity. The community functional groups and dominant families varied significantly across different land-use types， with herbivorous insects being the predominant group in all habitats. Different functional groups responded differently to environmental conditions： predators preferred warm， low-vegetation， and resource-rich environments. Detritivores favored tall， dry environments with low biomass. And herbivores preferred moist environments with sparse vegetation. Correlation analysis revealed that soil temperature， plant species richness， and aboveground biomass were the key influencing factors （P<0.001）. Multivariate analysis showed significant differences in community composition among the different land-use types （R²=0.238， P<0.05）. In conclusion， land-use management regulates insect community structure and function by altering vegetation and soil conditions. This study provides a reference for land-use changes aimed at biodiversity conservation in the Bashang region.

To investigate whether seasonal freeze-thaw promotes the emission of nitrous oxide （N₂O） and accelerates the gaseous loss of nitrogen in the talus plateau vegetation ecosystem， this study focused on the grassland （Thylacospermum caespitosum） pad vegetation at an altitude of 4000-4400 m on the Gangshigacha snow peak in the eastern part of the Qilian Mountains. The soil （0-30 cm） temperature， humidity， nutrient dynamic characteristics， and N₂O flux were monitored continuously for two years. The results showed that the soil experienced approximately 70 daily freeze-thaw cycles throughout the year， divided into four periods： unstable thawing period （25 times）， stable thawing period， unstable freezing period （45 times）， and stable freezing period. For every 100-meter increase in altitude， the average start and end time of soil freeze-thaw was delayed or advanced by 3.88 days. The N₂O emission was the most significant during the unstable thawing period （accounting for only 5.5%-6.8% of the entire year）， with a cumulative emission （225.97 g·hm^-2） accounting for 35.88% of the annual total， a maximum emission rate of 24.52 μg·m^-2·h^-1， an average flux of 13.63 μg·m^-2·h^-1， which was 1.39 times the annual average， and the cumulative emission during the non-growing seasons （excluding the stable thawing period） accounted for as high as 74.09%. The emission was dominated by soil water and heat， pH， and substrate scarcity， leading to low production. Under climate warming， the freeze-thaw driven nitrogen gas loss of N₂O in the ice margin zone intensified， and further research on the water and heat conditions and nitrogen transformation mechanism is needed.

Chicory （Cichorium intybus L.） is a perennial forage extensively utilized in livestock production. The magnesium-dechelatase involved in chlorophyll degradation plays a pivotal rolein regulating chlorophyll breakdown and is a key factor in the control of stay-green traits of plants. Enhancing the stay-green phenotype is critical for improving chicory’s resilience to environmental stresses. In this study， two putative SGR （Stay-Green） genes were preliminarily identified in the chicory genome， and designated as CiSGR and CiSGRL based on their respective phylogenetic affiliations to the SGR and SGRL subfamilies. The proteins encoded by these genes were composed of 274 and 232 amino acids， respectively. Structural domain analysis revealed that both CiSGR and CiSGRL possessed chloroplast transit peptide domains， highly conserved SGR domains， and variable regions at the C-terminus. Cis-regulatory element analysis indicated that the promoters of CiSGR and CiSGRL contained light-responsive， hormone-related， and stress-inducible transcriptional elements. Subcellular localization assays demonstrated that CiSGR predominantly localized to chloroplasts and nuclei， whereas CiSGRL primarily resided in nuclei and cytoplasm. Tissue-specific expression profiling showed the highest transcript levels of both genes in stems and significant induction under six different abiotic stress conditions. This systematic identification and analysis of chicory SGR and SGRL genes provides a theoretical foundation for strategies aimed at improving chicory forage yield and quality.

In order to alleviate the pressure caused by the shortage of forage grass in the alpine region of Xizang， Elymus nutans ‘Baqing’ was used as the research object in this experiment. A two-factor split-plot design was used. The main plot was the amount of nitrogen fertilizer added， and the sub-plot was the sowing rate. The amount of nitrogen fertilizer added was N₁ 0 kg·hm^-2， N₂ 60 kg·hm^-2， N₃ 120 kg·hm^-2， N₄ 180 kg·hm^-2， N₅ 240 kg·hm^-2 and N₆ 300 kg·hm^-2. The sowing rate was D₁ 15.0 kg·hm^-2， D₂ 22.5 kg·hm^-2 and D₃ 45 kg·hm^-2， so as to screen out the optimal planting configuration combination of ‘Baqing’ forage production. The results showed that under the same sowing rate， with the increase of nitrogen application rate， the production performance and nutritional quality of ‘Baqing’ were increased to varying degrees. Under the same nitrogen application rate， with the increase of sowing rate， the production performance and nutritional quality of ‘Baqing’ showed a trend of increasing first and then decreasing. Principal component analysis showed that 240 kg·hm^-2 nitrogen application rate and 22.5 kg·hm^-2 sowing rate were the optimal planting configuration for the production of ‘Baqing’. The above optimal planting configuration has certain theoretical reference value and production guiding significance for the promotion and utilization of ‘Baqing’ in the alpine region of Lhasa， Xizang.

Algal crusts represent a crucial type of biological soil crust in desert grasslands and serve as an important significant “ecological engineer”. They play a vital role in soil stabilization， water retention， wind erosion resistance， and carbon and nitrogen sequestration. However， researches on the effects of different grazing intensities on the characteristics of algal crusts in desert grasslands remains relatively limited. Based on a long-term grazing experiment platform （2004-present） in the desert grassland of Siziwang Banner， Inner Mongolia， in this study we investigated the impacts of varying grazing intensities on the algal crusts characteristics and identified the key driving factors. We measured the coverage， thickness， chlorophyll-a content of algal crusts， as well as related soil physicochemical properties under different grazing intensities. The results showed that as grazing intensity increased， the coverage， thickness， and chlorophyll-a content of algal crusts significantly decreased （P<0.05）. Structural equation modeling further revealed the key soil factors driving changes in algal crusts， among which soil available nitrogen was the most critical factor influencing characteristics of algal crusts. This study demonstrated that moderate and heavy grazing significantly inhibited the growth of algal crusts in desert grasslands， with soil bulk density， capillary water holding capacity， and soil available nitrogen were the most closely related factors to the changes in algal crusts characteristics. To maintain the ecological functions of algal crusts in desert grassland ecosystems， it is essential to strictly control grazing intensity， as long-term high-intensity grazing will lead to their severe degradation.

To elucidate the multilevel drivers of stocking rate increase on plant community state transition in desert steppe， this study was performed in a long-term grazing manipulation platform （2004-present） in Stipa breviflora desert steppe of Inner Mongolia. Four grazing intensity treatments were established： no grazing （CK）， light grazing （LG，0.91 sheep units·hm^-2·half-year^-1）， moderate grazing （MG， 1.82 sheep units·hm^-2·half-year^-1）， and heavy grazing （HG， 2.71 sheep units·hm^-2·half-year^-1）. Based on data from 145 monitored quadrats in representative plots， a state transition probability matrix was constructed， integrating species interaction networks， functional group succession， and plant family closure analysis. The results showed that： （1） Plant population network complexity peaked during the stage of LG transition to MG （with only 4 isolated species）， whereas core species （e.g.， the disappearance of Teloxys aristata） reduced and isolated species sharply increased to 15 at the HG stage； （2） As stocking rate increased， the transition probabilities from shrub-subshrub （SS） and perennial forbs （PF） to perennial grasses （PG） rose， while the transition probability from PG to annual-biennial plants （AB） increased by more than 30% under HG； （3） The receiving capacity of the Poaceae （POA） strengthened with increasing stocking rate， whereas the biomass proportion of Asteraceae （AST） declined. In summary， a stocking rate exceeding 1.82 sheep units·hm^-2·half-year^-1 triggered the critical threshold for community degradation. In contrast， moderate grazing （LG-MG） maintained community stability through species redundancy， optimized resource allocation among functional groups， and the formation of closed-loop transitions between plant families. This study provides a multidimensional theoretical foundation for early warning of desert steppe degradation and targeted restoration.