Reaumuria songarica is a key dominant species in the desert regions of northern China. The selection of appropriate seed source and the determination of optimal seed harvesting times are critical for the development and utilization of its germplasm resources. In this study, nine R. songarica habitats with varying precipitation levels were identified in the HeHuang Valley. We determined the optimal seed harvesting period and evaluated seed traits, germination characteristics, and initial seedling growth at this optimal period harvest time. The results indicated that the optimal harvesting window for R. songarica seeds is between 60 and 100 days after flowering, depending on the precipitation of the seed source area. Species origin accounted for the largest variation in seed germination characteristics and seedling growth, with the highest coefficient of variation observed in the vitality index (28.44%) and the lowest in seed viability (3.78%). In the standard germination test, seed germination was primarily influenced by 1000-seed weight and seed viability, while seedling growth was mainly affected by seed electrical conductivity. Seed drought germination resistance was most influenced by seed biofilm integrity and seed size. In conclusion, high-quality, drought-tolerant R. songarica germplasm can be obtained by selecting drought-prone seed source areas in the HeHuang Valley and harvesting seeds between 90 and 100 days after flowering. These findings underscore the critical role of precipitation at the seed source in shaping seed and seedling traits, providing valuable guidance for the future development and utilization of R. songarica germplasm resources.

Soil tillage management is one of the effective measures to restore degraded terrestrial ecosystems; however, the responses of soil and plants to different tillage management in severely degraded alpine meadows have not been well addressed. In this study, three typical native grass species were planted in a degraded alpine meadow using two tillage management measures: the no-tillage reseeding (RG) and the cultivated grassland (CG). Soil and plant physicochemical properties, along with soil bacterial community structure, were analyzed. Results showed that the coexistence of Cyperaceae and Gramineae in no-tillage reseeding increased community diversity and shifted dominance from poisonous weeds to desirable functional groups, compared with cultivated grassland and severely degraded alpine meadows. No-tillage reseeding enhanced soil organic carbon (SOC), total nitrogen (TN), and soil microbial biomass carbon (SMC), microbial nitrogen (SMN), and microbial phosphorus (SMP) more effectively than cultivated grassland. These improved soil physicochemical properties (particularly soil water content and bulk density) served as key drivers shaping the bacterial communities. Specifically, no-tillage reseeding enriched carbon cycle-related functional groups, reduced nitrogen cycle-related groups, and promoted a more stable plant-bacterial bipartite network characterized by higher numbers of nodes and links, as well as more positive interactions. Notably, the regulatory effects of no-tillage reseeding on bacterial communities and functions were directly mediated by soil properties, and were independent of plant community changes. Our findings reveal that no-tillage reseeding restores degraded alpine meadows via a soil-centered mechanism: by minimizing disturbance to improve soil structure and nutrient availability, which in turn optimizes plant community structure and bacterial community stability. This process-based understanding provides a scientific basis for developing effective management strategies for degraded alpine ecosystems.

Introduction:Alpine meadows provide a critical natural laboratory for investigating interactions between ecosystem degradation and biogeochemical processes across elevational gradients. Methods:This study examines how degradation states and elevation (3,700 m vs. 4,300 m) influence soil fungal community composition, diversity, and network architecture in Qinghai-Tibetan Plateau grasslands. Through comparative analysis of degraded and intact meadows, we reveal fundamental shifts in belowground ecology driven by environmental change. Results:Key environmental parameters showed differential responses: soil organic matter (SOM) decreased significantly with degradation, while soil water content exhibited elevation-dependent patterns (p < 0.05). High-throughput sequencing identified Ascomycota, Mortierellomycota, and Basidiomycota as dominant phyla across all samples. Redundancy analysis (RDA) analysis demonstrated that edaphic factors explained 71.3% of fungal community variation, with SOM emerging as the principal driver (p = 0.001). Interestingly, meadow degradation led to an increase in fungal species diversity, thereby simplifying network complexity. Fungal communities show greater sensitivity to degradation than elevational gradients. Discussion:Our results provide a mechanistic framework for predicting fungal community responses to environmental change, with implications for alpine ecosystem management. Future restoration efforts should prioritize SOM conservation and monitor network properties as early warning indicators of ecosystem degradation.

Flowering Aster species (Aster spp.) native to the high-altitude (3753 m on average) Three Rivers Source Region are frequently damaged by Tephritis angustipennis, imposing significant stress that negatively impacts their survival and productivity. This study reveals that pest stress enhances antioxidant enzyme activity (CAT, POD, SOD, and PPO) and increases secondary metabolites, particularly flavonoids, in Aster flowers. Integrated transcriptomic and metabolomic analyses identified differential responses among three Aster varieties exhibiting distinct resistance levels. We found that increasing pest stress, particularly under serious-hazard (HH) conditions, upregulates resistance-related genes and promotes the accumulation of phenolic and terpenoid compounds. Pest feeding activates the flavonoid biosynthesis pathway, with key enzyme genes (PAL, CAD, HCT, FLS, and CYP) being upregulated, reflecting a rapid physiological response that enhances resistance. Notably, flavonoid synthesis is dynamically regulated in response to stress. Under HH conditions, quercetin and kaempferol levels decrease, while phlorizin, kaempferide, sakuranetin, and isosakuranetin increase, indicating a complex defense strategy. Overall, pest-induced flavonoid accumulation helps delay the process of flower aging and deterioration, thereby enhancing seed yield. These findings provide valuable insights into the molecular defense mechanisms of Aster spp., offering potential targets for breeding pest-resistant varieties and developing effective pest management strategies.

Aster varieties are widely used for medicinal purposes, landscaping, and ecological restoration, but their growth and reproduction are significantly threatened by the seed predator Tephritis angustipennis (Diptera: Tephritidae). The cultivation of pest-resistant varieties offers an effective, economical, and eco-friendly approach to managing T. angustipennis infestations. This study evaluates the impact of T. angustipennis on ten Aster varieties in the Three Rivers Source Region (TRSR), with a focus on population density, plant damage rate, and the activity of resistance enzymes and insect-resistant metabolites. The results classified the ten varieties into four resistance groups: one highly resistant variety [HR: Aster altaicus (MQAA)], four moderately resistant varieties [MR: Aster asteroides (DRAA), Aster flaccidus (QLAF), Aster tongolensis (BMAT), Aster poliothamnus (MQAP)], two moderately susceptible varieties [MS: Aster diplostephioides (QLAD), Aster souliei (DRAS)], and three highly susceptible varieties [HS: A. diplostephioides (MQAD), Aster yunnanensis var. labrangensis (MQAY), Aster farreri (MQAF)]. Notably, HR and MR varieties exhibited significantly higher activities of catalase (CAT), peroxidase (POD), superoxide dismutase (SOD), phenylalanine ammonia lyase (PAL), polyphenol oxidase (PPO), trypsin inhibitor (TI), and chymotrypsin inhibitor (CI), as well as higher contents of tannins (TN) and flavonoids (FN), compared to MS and HS varieties. Specifically, the HR variety (MQAA) showed the highest levels of CAT, POD, SOD, and TN, significantly enhancing its resistance to T. angustipennis. Statistical analyses further revealed that MDA, TN, FN, and antioxidant enzyme activities were found to be key factors influencing insect resistance across the different varieties and resistance levels. These findings enhance our understanding of the physiological and biochemical mechanisms underlying resistance in Aster spp. and offer valuable insights for developing integrated pest management strategies. By identifying and promoting resistant varieties, this study lays the groundwork for effective, sustainable control measures that protect Aster crops from T. angustipennis damage.

Shrub encroachment in alpine meadows is rapidly occurring under global warming, significantly impacting the regulation of runoff, soil water retention and groundwater conservation. However, the dynamics of soil moisture redistribution following shrub encroachment are poorly understood. Here, the groundwater recharge and water uptake strategies of vegetation were explored through stable water isotope analysis to determine the mechanism of moisture redistribution on the Qinghai-Tibetan Plateau following shrub encroachment. The results indicated that the soil moisture content (SMC) of alpine shrublands (AS) increased significantly compared with that of alpine meadows (AM) and bare lands (BL), which resulted from a decrease in root biomass and an increase in capillary porosity. Furthermore, groundwater recharge from BL and AS was 4.17 and 3.30 times greater than that from AM (12 %), respectively, which was attributed to changes in soil porosity induced by the disappearance of mattic epipedons. In AS, Salix cupularis took up 57 % of the soil moisture from soil depth of 0-10 cm due to high root biomass, and this uptake level was significantly greater than that of Kobresia pygmaea (12 %). Overall, the soil moisture redistribution processes were markedly affected by changes in vegetation and soil parameters under shrub encroachment. These findings suggest that rapid shrub encroachment can accelerate rainfall infiltration and soil moisture dynamics, which can significantly influence hydrological processes on the Qinghai-Tibetan Plateau.

Background The source region of the Three Rivers is a concentrated distribution area of alpine grassland. Due to intensified human interference and unsustainable land use, the vegetation and soil in these grasslands have undergone severe degradation, resulting in extensive areas of secondary bare land known as “black soil beach”. A specific form of this degradation is referred to as “black-soil mountain”. To address soil degradation in this region, the establishment of artificial grassland has been proposed. Recent research on grassland restoration has increasingly focused on belowground processes, particularly the role of soil microbial communities in soil recovery. Methods This study quantitatively analyzed vegetation characteristics, soil nutrients, microbial community structure, and influencing factors across three grassland types: artificial grassland (AG), black-soil mountain degraded grassland (BG), and natural grassland (NG). Standard laboratory analyses and the phospholipid fatty acid (PLFA) method were employed. Results The establishment of artificial grassland significantly increased aboveground biomass and the contents of soil organic carbon, total nitrogen, and total phosphorus, while notably reducing species richness. A total of 29 PLFA biomarkers were detected across the three grassland types, with AG showing significantly higher biomarker content than BG and NG. Key PLFA biomarkers included 16:1 w7c, 18:1 w7c, 15:0 iso, 15:0 anteiso, 16:00, and 18:1 w9c. Among microbial groups, bacteria were most abundant, followed by fungi, actinomycetes (act), and arbuscular mycorrhizal fungi (AMF). Compared to BG, AG exhibited significantly lower G+/G−and saturated-to-monounsaturated fatty acid (Sat:mono) ratios. Correlation analysis revealed that total PLFA, bacterial (B), fungal (F), G+, and G−contents were significantly or highly significantly positively correlated with soil organic carbon, total nitrogen, and water content (P < 0.01; P < 0.001). Redundancy analysis (RDA) showed that two principal components explained 76.96% and 13.74% of the variation in microbial community structure, with soil organic carbon and total nitrogen identified as the main driving factors. Conclusion The establishment of artificial grassland is an effective strategy for restoring black-soil mountain degraded grassland. Monitoring microbial PLFA diversity and composition provides a reliable index for assessing soil environmental changes and nutrient dynamics. However, even after five years of restoration, the soil functionality of artificial grassland does not fully recover to the level of natural grassland.

Xerophytes employ multidimensional adaptation strategies, including physiological metabolism, photosynthetic regulation, anatomical restructuring, and hydraulic system adjustments, to cope with drought stress. However, most existing studies focus on drought resistance mechanisms in mature shrubs in natural habitats, while the response patterns and survival strategies at the seedling stage remain poorly understood. In this study, we investigated the physiological mechanisms of drought adaptation in seedlings of the typical desert shrub Reaumuria songarica under four drought gradient treatments (CK: control; LS: light stress; MS: moderate stress; HS: heavy stress) using pot-based water control experiments. The results showed that drought stress significantly induced the accumulation of reactive oxygen species (ROS) (oxygen free radicals increased by 151.05 %, and H2O2 increased by 86.79 %). R. songarica seedlings maintained redox homeostasis by upregulating the activities of antioxidant enzymes such as catalase (CAT) and superoxide dismutase (SOD). Simultaneously, osmotic adjustment substances such as proline and soluble proteins accumulated significantly, with proline content in the HS group increasing nearly 10-fold (982.86 %) compared to CK, effectively mitigating cellular dehydration damage. The mechanism of photosynthetic inhibition evolved dynamically with stress intensity: stomatal limitation dominated under mild drought (stomatal conductance decreased by 15.79 %, and intercellular CO2 concentration decreased by 23.4 %), while non-stomatal limitation became the primary factor under severe drought (chlorophyll a and b contents decreased by 88.17 % and 125.67 %, respectively). R. songarica also thickened the palisade tissue (increased by 9.01 % in LS), reduced the spongy tissue (decreased by 26.74 % in HS), and decreased stomatal aperture (decreased by 52.87 % in HS) and stomatal density (decreased by 48.83 % in HS), constructing a dual-functional leaf structure for water conservation and carbon fixation to minimize water loss. In the early stages of drought, R. songarica adopted an "efficiency-first" strategy, which shifted to a "safety-first" mode under severe stress, optimizing structural traits to resist embolism risks. This study systematically reveals, for the first time, the multidimensional dynamic adaptation strategies of R. songarica seedlings to gradient drought, providing a theoretical basis for seedling selection and precise water management in desert vegetation restoration, with significant practical implications for ecological reconstruction in arid regions.

Aster (Asteraceae) species as one of the traditional Tibetan medicinal plants in China have high useful medicinal and unique ornamental value; the market demand has been gradually increasing. In this study, seven species of Aster were selected from the Qinghai-Tibet Plateau, and the MaxEnt model was used to investigate their potential distribution in China and the changes in their suitable habitat under future climate conditions based on the current survey and distribution data of specimens on the site and six to eight environmental variables. The results showed that temperature and precipitation were important limiting factors affecting the distribution of Aster, and Bio2, Bio3, and Bio10 were common environmental factors influencing the factors of Aster species. Under the current climate, the mainly potential distributed region of the seven Aster species in the Qinghai-Tibet Plateau exists. Under projected future climate scenarios, the suitable habitats of A. asteroides and A. diplostephioides will shrink significantly, while those of A. farreri, A. poliothamnus, A. souliei, A. tongolensis, and A. yunnanensis var. labrangensis will expand accordingly. Environmental factors provide a large gain in predicting the distribution of Aster species. Among the environmental variables, isothermality (Bio3) induced the largest impact on SDM and contained the most useful information for A. diplostephioides (55.9%), A. souliei (41.5%) and A. yunnanensis var. labrangensis (27.1%), while A. tongolensis (27.9%) and A. poliothamnus (26.8%) were more significantly affected by the temperature seasonality (Bio4); A. asteroides (66.3%) and A. farreri (21%) were more significantly affected by the mean temperature of the warmest quarter (Bio10). The study findings suggest that the distribution range of seven species of Aster will be greatly impacted by climate change. This research helps identify the limiting factors affecting the natural distribution and potential suitable areas for Aster species, which can inform conservation efforts, plant introduction, acclimatization, domestication, and cultivation of Aster.

Plant diversity plays a crucial role in maintaining the stability of ecological function. Based on field investigations and experimental analyses, artificial grassland plots with varying sowing times, adjacent natural grassland (CK), and open-pit coal mine dumps in the Muli mining area of Qinghai Province were selected as research subjects for this study. The characteristics of plant diversity and community stability were measured and analyzed, and the relationships between these factors and their influencing variables were evaluated. The results indicated significant differences in the vegetation community characteristics and plant diversity among the various grasslands. Coverage, aboveground biomass, belowground biomass, soil total nitrogen, and soil total carbon were the highest when the growth period was three years. Plant diversity and community stability in the natural grassland were significantly greater than that in the artificial grassland and open-pit coal mine dumps. A significant positive correlation was observed between plant diversity and community stability, suggesting that plant diversity can serve as an index of community stability. The order of stability, from highest to lowest, was CK > 11a > 10a > 8a > 9a > 6a > 7a > 3a > 2a > 1a > 0a. Years were identified as the primary factors affecting plant diversity and community stability by altering the soil pH. These results elucidate the relationships and driving mechanisms between plant diversity and community stability in grasslands, providing a scientific basis for maintaining community stability in artificial grassland ecosystems in alpine mining areas.

As primary regulators of ecosystem multifunctionality, soil microorganisms are impacted by various stressors, including climate change and overgrazing. Presently, an increasing area of alpine meadows on the Qinghai Plateau is experiencing degradation. However, it is not yet clear how the multifunctionality of the meadow ecosystem, the microbial community, and their interactions respond to degradation. We examined the vegetation, soil, microbial, and enzyme activity indicators in the non-degradation and extreme degradation of alpine meadows on the Qinghai Plateau. Meanwhile, we assessed the complexity of fungal networks and the ecosystem's multifunctionality. Results showed that compared to non-degraded meadows, the majority of the properties in the soil decreased significantly, especially in available potassium (10.7%-57.8%), microbial biomass carbon (67%-73.6%), and sucrase (53.2%-77.5%). Meanwhile, ecosystem multifunctionality decreased significantly, and the complexity of the fungal network became simpler. The linear fitting further demonstrated that the degradation of the alpine meadow reduced the complexity of the soil fungal network, leading to a significant decline in ecosystem multifunctionality (r = 0.552-0.759, p<0.001). In summary, the simplification of the fungal community due to degradation could impair the multifunctionality of the ecosystem. Consequently, when managing degraded alpine meadows, it will be important to focus on the network characteristics of soil microorganisms. We suggest restoring the complexity of soil microbial communities, which may be the foundation and prerequisite for restoring grassland ecosystem functions.

Soil fungi serve as key mediators of belowground ecological processes; however, the altitudinal distribution patterns and their driving mechanisms of soil fungal communities in alpine shrubland ecosystems remain poorly understood. In this study, soil samples were collected from Potentilla fruticosa shrubs at different altitudes, and their physical and chemical properties were determined. Illumina MiSeq sequencing technology was used to study the characteristics of soil fungal communities at different altitudes (3400, 3700, 4000, and 4300 m), and the driving factors affecting the composition of soil fungal communities were found through variance analysis and redundancy analysis. With the increase in altitude, species diversity decreased while total phosphorus and available phosphorus increased. Compared with 3400 m, the diversity index (Sobs, Chao1, and ACE index) of the soil fungal community at 4000 m is the highest, and that at 4300 m is the lowest. NMDS analysis showed that there were significant differences among soil fungal community structures at different altitudes. Redundancy analysis (RDA) indicated that available potassium, available phosphorus, and the Shannon–Wiener diversity index were the primary factors influencing the variation in soil fungal communities along the elevation gradient. Furthermore, the impact of soil physical and chemical properties on soil fungal communities was found to be more pronounced than that of plant characteristics. Network analysis shows that the network complexity is the highest at 4300 m above sea level. These studies provide a new perspective and basis for understanding the distribution pattern of soil fungi in the rhizosphere Potentilla fruticosa in the eastern Qinghai–Tibet Plateau.

Introduction:On degraded grasslands, rest-grazing and fertilization measures have been widely applied. In alpine grasslands, numerous studies have examined the impact of rest-grazing and fertilizer application on microbial communities. However, the impact of these measures on the microbial community in Carex tibetikobresia meadows remains largely understudied. Furthermore, the relationship between aboveground vegetation and soil components under these treatments warrants further investigation. Methods:We conducted a field control experiment in Dawu Town, Maqin County, China, during the winter-spring pasture regreen-up period. The primary treatment consisted of five rest-grazing durations, while the secondary treatment involved nitrogen addition. Results and discussion:The results indicated that, under rest-grazing treatment, the levels of soil nitrogen can improve and ammonium nitrogen (NH₄+-N) was the primary environmental factor affecting microbial biomass. It showed a significantly negatively correlated with bacteria and gram-negative bacteria (G-), but a positive correlation with the ratio of gram-positive bacteria to gram-negative bacteria (G+:G-). Furthermore, without fertilization treatment, the ratio of fungi to bacteria (F:B) and G+:G- reached a maximum at rest-grazing for 30 days. In contrast, under fertilization treatment, microbial biomass carbon (MBC) became the dominant environmental factor affecting microbial biomass. It was negatively correlated with G-, but positively correlated with the ratio of F:B and G+:G-. Rest-grazing increases soil inorganic nitrogen and promotes actinomycetes growth, providing a viable strategy for restoring inorganic nitrogen levels in degraded grasslands. On the other hand, fertilization reduced the biomass of total phospholipid fatty acids (PLFAs) and all PLFAs groups. Consequently, the recommendation is that fertilization measures should not be utilized on this grassland and that a 30-day rest-grazing durations is preferable. Additionally, we observed inconsistent responses of microbial communities in the Carex tibetikobresia meadow and alpine meadows to rest-grazing and fertilization. These findings offer valuable insights into how fertilization modifies microbial responses to rest-grazing, providing important guidelines for the management of degraded Carex tibetikobresia meadows.

[Objective] The study aims to explore the influence of spring rest grazing on the niche of Carex tibetikobresia meadow plants, and to provide data and theoretical guidance for grassland restoration and biodiversity protection. [Methods] Grazing and four grazing-off time treatments (20, 30, 40, and 50 d) were set during the green-returning period. Plant community was investigated in the middle of July of the second year, and the grazing-off time were taken as the environmental gradient to study the niche of plant populations in the C. tibetikobresia meadow. [Results] After 30, 40, and 50 days of rest grazing, the importance value and aboveground biomass of Cyperaceae were significantly increased compared to grazing, while the importance value of poisonous weeds showed the opposite trend. The aboveground biomass of Cyperaceae, Gramineae, and broad-leaved edible grasses were increased most significantly after 50 days of rest grazing, increasing by 220.99%, 69.73%, and 139.37%, respectively. The niche width (NB) of C. tibetikobresia S. R. Zhang, Helictotrichon tibeticum (Roshev) Holub, Elymus nutans Griseb, and Festuca rubra were the largest (0.999), while that of Ranunculus indivisus (Maxim.) Hand.-Mazz. was the smallest (0.889). There were 55 pairs with niche overlap value (N O) greater than 0.990, accounting for 26.10% of the total, and 3 pairs with N O less than 0.75, accounting for 1.43%. [Conclusion] Longer rest grazing time in spring promotes the growth of Cyperaceae and Gramineae, and inhibites the growth of poisonous weeds. The higher the importance value of C. tibetikobresia meadow species, the wider its niche width, which is more conducive to the growth of excellent pasture and can effectively promote the restoration of grassland.

[Objective]The Yarlung Zangbo River is the most important river in the Tibetan Plateau,and the study of aboveground biomass and species diversity of the Yarlung Zangbo River is of great significance for the understanding of grassland resources and ecological conservation in the region.[Methods]This study investigated the characteristics of vegetations along elevation gradients in the alpine meadows in the upper reaches of the Yarlung Zangbo River,the distributional differences of aboveground biomass and spe-cies diversity along the gradients,and the relationship between aboveground biomass and species diversity.We also studied the effects of environmental factors on aboveground biomass and species diversity.[Results](1)There was no significant relationship between aboveground biomass and elevation,tempera-ture and precipitation(P＞0.05).(2)Species diversity indices showed a significant negative correlation with elevations,and the Shannon-Weiner index(H)and Patrick index(R)showed a declining trend with elevation.Species diversity showed a significant positive correlation with temperature and precipitation(P＜0.05).(3)Aboveground biomass and diversity showed a negative correlation,and the explanation of aboveground biomass by the Shannon-Weiner index(H)reached 70％(P＜0.01).[Conclusion]There was no significant correlation between aboveground biomass and elevation,and species diversity indices showed a significant negative correlation with elevation.These results provide basis for the rational utiliza-tion of grassland resources and species diversity conservation in the upper reaches of the Yarlung Zangbo River basin.

Poa pratensis L. cv. Qinghai is a major grass species utilized for the restoration of the "black beach" in the Three River Source region. However, its seed production has been relatively underdeveloped. To enhance the seed yield, this experiment aimed to determine the optimal application ratio and amount of base fertilizer to achieve high-yield production of seeds in Poa pratensis. Using the "3414" fertilization scheme, the plants (cv. Qinghai) were fertilized with a base fertilizer varying in ratios and quantities of nitrogen, phosphorus, and potassium. Regression analysis was employed to identify the most appropriate base fertilizer application scheme, in order to increase the seed yield of its. K fertilizer had no significant effect on the seed yield of Poa pratensis, but applying K fertilizer (50 kg·hm−2) as base fertilizer improved the seed quality. Seed yield reached the highest level due to the increased number of seeds per panicle and reproductive tillers by applying fertilizer comprising 130 kg·ha−1 N, 100 kg·ha−1 P, and 50 kg·ha−1 K. This study demonstrated that the highest number of seeds per panicle and reproductive tillers per square meter were key field components enhanced by the optimal formulation of base fertilizer for seed production of Poa pratensis.

About 35% of grassland in Sanjiangyuan area of China has degenerated into black-soil mountain. Artificial grassland is considered to be an effective measure to alleviate the severely degraded grassland in the alpine region of the three rivers and has been widely used. However, the pattern, potential function, and changes of carbon and nitrogen contents of soil microorganisms in degraded grassland in Heimushan by planting artificial grassland are still unclear. In this study, mixed-sown artificial alpine grassland (AG) was the focus of our study, whereas degraded black-soil mountain grassland (BG) and natural alpine grassland (NG) served as controls. Illumina 16S and ITS gene sequence analyses were used to analyze the community structure of the soil bacteria and fungi. The functional groups of NG, AG, and BG were predicted using the FAPROTAX and FUNGuild databases. In addition, the levels of soil carbon, nitrogen, and soil enzyme activities were evaluated. The results indicated a significant increase in the aboveground biomass of BG due to the planting artificial grassland. Moreover, the contents of total carbon (TC), total nitrogen (TN), ammonium nitrogen ( NH 4 + - N ), microbial biomass carbon (MBC), microbial biomass nitrogen (MBN), and leucine aminopeptidase (LAP) increased in the soil. Planting artificial grasslands changed the composition of bacterial and fungal communities. Among these, the bacterial community was more sensitive to planting artificial grasslands. The relative abundance of bacterial functional groups involved in carbon and nitrogen cycling changed significantly, suggesting that bacteria may play a role in regulating nutrient cycling during artificial grassland planting. Soil TC, TN, LAP, and NH 4 + - N affected the microbial community structure related to carbon and nitrogen. NH 4 + - N and β-1,4-glucosidase were carbon and nitrogen factors, respectively, that affected functional changes in fungi. These results indicate that planting artificial grasslands can effectively enhance the productivity of degraded black-soil mountain and regulate soil microbial communities and soil physical and chemical properties.

The degradation of temperate desert type rangeland leads to decreased vegetation diversity and soil nutrients levels. Grazing prohibition and artificial revegetation are common strategies for vegetation restoration. However, it is currently unknown the duration of grazing prohibition and artificial revegetation affect soil microorganisms. Therefore, experiments on grazing prohibition duration and artificial revegetation were conducted to explore the response of soil microorganisms to these measures. Field experiments were conducted during the peak plant growth season in Guide County, China, to evaluate methods involving grazing prohibition and artificial revegetation. We established six experimental sites, which were grazing prohibition for fifteen years (P15), grazing land located near P15 (P15-CK), grazing prohibition for eight years (P8), grazing land located near P8 (P8-CK), artificial revegetation for three years (A3), and wasteland located near A3 (A3-CK). The results showed that artificial revegetation measures decreased the plant diversity, whereas grazing prohibition for eight years increased it. Artificial revegetation and grazing prohibition measures led to an increase in pH and total carbon, and a decrease in total nitrogen and total phosphorus. The amount of total PLFA increased with artificial revegetation, whereas grazing prohibition resulted in a decrease of total PLFA. Artificial revegetation and grazing prohibition measures decrease the relative abundance of the Ascomycota phylum and the fungal diversity. In addition, the study found that fungal communities were primarily influenced by soil factors such as ammonium nitrogen, pH, and total carbon, rather than by plants. Vegetation restoration enhances the accumulation of total soil carbon and alters fungal community composition and diversity. The effects of artificial revegetation and grazing prohibition measures on the amount of total PLFA varied. These findings provide important information that vegetation restoration promotes soil nutrient accumulation but reduces fungal diversity, which can inform the restoration of degraded temperate desert type rangeland.

IntroductionSeed traits related to recruitment directly affect plant fitness and persistence. Understanding the key patterns and influencing factors of seed trait variations is conducive to assessing plant colonization and habitat selection. However, the variation patterns of the critical seed traits of shrub species are usually underrepresented and disregarded despite their vital role in alpine desert ecosystems.MethodsThis study gathered seeds from 21 Asterothamnus centraliasiaticus populations across the Qinghai-Tibetan Plateau, analyzing geographical patterns of seed traits to identify external environmental influences. Additionally, it explored how seed morphology and nutrients affect germination stress tolerance, elucidating direct and indirect factors shaping seed trait variations.ResultsThe results present substantial intraspecific variations in the seed traits of A. centraliasiaticus. Seed traits except seed length-to-width ratio (LWR) all vary significantly with geographic gradients. In addition, the direct and indirect effects of climatic variables and soil nutrients on seed traits were verified in this study. Climate mainly influences seed nutrients, and soil nutrients significantly affect seed morphology and seed nutrients. Furthermore, climate directly impacts seed germination drought tolerance index (GDTI) and germination saline-alkali tolerance index (GSTI). Seed germination cold tolerance index (GCTI) is influenced by climate and soil nutrients (mostly SOC). GDTI and GSTI are prominently influenced by seed morphology (largely the seed thousand-grain weight (TGW)), and GCTI is evidently affected by seed nutrients (mainly the content of soluble protein (CSP)).DiscussionThe findings of this study amply explain seed trait variation patterns of shrubs in alpine desert ecosystems, possessing significant importance for understanding the mechanism of shrub adaptation to alpine desert ecosystems, predicting the outcomes of environmental change, and informing conservation efforts. This study can be a valuable reference for managing alpine desert ecosystems on the Qinghai-Tibetan Plateau.

Tephritis angustipennis (Diptera: Tephritidae) and Campiglossa loewiana (Diptera: Tephritidae) are phytophagous pests in China. Their damage has significantly impacted the collection and cultivation of germplasm resources of native Asteraceae plants. However, the genetic characteristics and structure of their population are unclear. This study focused on the highly damaging species of T. angustipennis and C. loewiana collected from the three-river source region (TRSR). We amplified the mitochondrial cytochrome C oxidase subunit I (mtCOI) gene sequences of these pests collected from this area and compared them with COI sequences from GenBank. We also analyzed their genetic diversity and structure. In T. angustipennis, 5 haplotypes were identified from 5 geographic locations; the genetic differentiation between France population FRPY (from Nylandia, Uusimaa) and China populations GLJZ (from Dehe Longwa Village, Maqin County), GLDR (from Zhique Village, Dari County), and GLMQ (from Rijin Village, Maqin County) was the strongest. GLJZ exhibited strong genetic differentiation from GLDR and GLMQ, with relatively low gene flow. For C. loewiana, 11 haplotypes were identified from 5 geographic locations; the genetic differentiation between the Chinese population GLMQ-YY (from Yangyu Forest Farm, Maqin County) and Finnish population FDNL (from Nylandia, Uusimaa) was the strongest, with relatively low gene flow, possibly due to geographical barriers in the Qinghai-Tibet plateau. Only 1 haplotype was identified across GLDR, GLMQ, and GLBM. High gene flow between distant locations indicates that human activities or wind dispersal may facilitate the dispersal of fruit flies and across different geographic. Geostatistical analysis suggested a recent population expansion of these 2 species in TRSR. Our findings provide technical references for identifying pests in the TRSR region and theoretical support for managing resistance, monitoring pest occurrences, analyzing environmental adaptability, and formulating biological control strategies for Tephritidae pests on Asteraceae plants.