Search Results (98)

Water and nitrogen supply are key factors limiting the establishment of alpine plant seedlings and the efficiency of ecological restoration on the Tibetan Plateau. As an endemic shrub to Tibet, the morphological and physiological response mechanisms of Piptanthus nepalensis (Hook.) D. Don to coupled water and nitrogen stress remain poorly understood. This study employed a pot experiment with a completely randomized two-factor design, incorporating five water gradients (0–100% field capacity, FC) and five nitrogen levels (0–4 g·plant⁻¹ urea). The aim was to elucidate the regulatory mechanisms of water/nitrogen coupling on Piptanthus nepalensis growth, physiology, and morphogenesis. The results indicated the following: (1) A significant water/nitrogen coupling effect was observed, with optimal water/nitrogen combinations producing pronounced synergistic effects. Principal component analysis (PCA) revealed that the first two axes cumulatively explained 99.32% of the morphological variation. The W3N3 treatment (40–60% FC water + 2 g·plant⁻¹ nitrogen) exhibited optimal growth traits and maximum leaf elongation, establishing the optimal water and fertilizer management threshold for this species. (2) Confronted with two starkly contrasting stresses—drought (W4, W5) and waterlogging (W1)—plants adopted convergent “conservative” morphological adaptation strategies (significantly reduced leaf length and width) to lower metabolic expenditure. (3) Photosynthetic physiological analysis revealed that under extreme water deficiency (W5) or waterlogging (W1) stress, intercellular CO₂ concentration (Ci) paradoxically increased, indicating a shift in photosynthetic suppression mechanisms from stomatal limitation to non-stomatal limitation (metabolic injury). (4) The Mantel Test confirmed that photosynthetic physiological traits significantly drove morphological trait variation (p < 0.001), establishing a close feedback loop between “physiological function and morphological structure”. Conclusions: Moderate water deficit (40–60% FC) combined with moderate nitrogen fertilization (2 g·plant⁻¹) effectively alleviates non-stomatal limitation and releases morphological constraints, thereby promoting rapid growth in Piptanthus nepalensis. This study reveals the phenotypic plasticity and convergent adaptation mechanisms of Piptanthus nepalensis under water/nitrogen co-stress, providing precise water and fertilizer management guidelines for vegetation restoration in degraded ecosystems of Tibet. Full article

Berberis amurensis var. quelpaertensis (Nakai) Nakai is an endemic shrub species in Korea with considerable conservation importance; however, information regarding its propagation remains limited. This study aimed to characterize its seed dormancy type and identify optimal germination requirements. Water imbibition tests demonstrated that seed weight increased by >21% in 24 h, indicating a permeable seed coat and the lack of physical dormancy (PY). Additionally, morphological analysis revealed that embryos were completely developed at the time of seed dispersal, indicating the non-occurrence of morphophysiological dormancy (MPD). The results from modified move-along and stratification experiments showed that germination was notably enhanced by cold stratification at 5 °C; however, it also occurred following a prolonged period (>68 weeks) of warm stratification alone. Therefore, we conclude that the seeds of B. amurensis var. quelpaertensis exhibit intermediate physiological dormancy, which may represent a “bet-hedging” strategy adapted to the unique conditions of their alpine environment. Full article

The Qinghai–Tibet Plateau (QTP) plays a crucial role in the terrestrial carbon cycle, but the gross primary productivity (GPP) estimates for the region remain highly uncertain due to limited flux observations and modeling challenges. Here, we integrated 65.2 site years of eddy covariance data from 19 flux sites with multi-source remote sensing observations to develop a data driven GPP model for the QTP. Eleven machine learning algorithms from two automated machine learning (AutoML) platforms, H2O AutoML and FLAML, were evaluated to construct an ensemble model named AutoML. The model showed strong performance at site-level across alpine meadow, steppe, wetland, and shrub ecosystems, achieving R² up to 0.95 and RMSE as low as 0.42 g C m⁻² d⁻¹. By validating extracted site-level GPP values from the upscaling GPP datasets against with flux observations, AutoML-GPP demonstrates overall superior or equivalent performance over global GPP products (FLUXCOM X-base, GOSIF, and FluxSat). Regional upscaling estimated a mean annual total GPP of 374.20 Tg C yr⁻¹ from 2002 to 2018, with a slight upward trend of 0.08 Tg C yr⁻¹. Spatially, higher GPP occurred mainly in the eastern QTP, with anomalies linked to climate extremes in 2008, 2010, and 2015. AutoML-GPP effectively captures climate-induced interannual anomalies in the QTP’s GPP, coinciding with GOSIF-GPP and FluxSat GPP, and outperforming the recent released well-known global upscaling flux dataset FLUXCOM X-base. This study provides improved GPP estimation for the QTP, offering new insights into carbon cycling and climate–vegetation interactions. Full article

Bumblebees are the most important pollinators in alpine areas. Their survival is vulnerable to anthropogenic disturbance. To comprehend the variation in bumblebee diversity in different habitat types and altitudinal gradient, this study carried out transect counting in three distinct habitat types and altitudinal gradient in the source area of the Bailong River between June and September from 2021 to 2022. The result indicates (1) high species richness in bumblebees, as 27 species and 1106 individuals from 9 subgenera were collected. It indicates that the Forest–Grassland ecotone has rich bumblebee diversity. Edge effective and suitable habitats bred rich bumblebees. (2) Species richness and abundance differed between three habitat types: alpine meadows had the highest; shrubs on the forest edge had the second highest; and grasslands had the lowest. (3) The distribution pattern in the altitude of bumblebees shows two peaks. The species richness and abundance of bumblebee are highest in the ranges of 3500–3700 m and 2900–3100 m, while 3100–3500 m is lower than the other altitude ranges, presumably because this range is just a large grassland with overgrazing. (4) The results of redundancy analysis indicate that environmental factors significantly affect the diversity of bumblebees. (5) The conservation measures should mainly focus on alpine meadows, as they are the most important habitat of the bumblebee. Reducing overgrazing in large-scale grasslands is beneficial to bumblebees as well as wildflower plants. Full article

Different approaches have been developed to assess the phenological dynamics of ecosystems. However, diverse data sources and extraction methods for assessing ecosystem phenology can result in discrepant and inaccurate results, especially across different types of vegetation under various climate classifications. Based on the phenology of dominant plant species (Phe_plant) obtained from ground monitoring in an alpine shrub meadow at Haibei Station (HBS) on the Qinghai–Tibetan Plateau and in a broad-leaved Korean pine forest at Changbai Mountain (CBF) in Northeastern China, we extracted vegetation phenology from the Normalized Difference Vegetation Index (Phe_NDVI) and photosynthetic phenology from gross primary productivity (Phe_GPP) using five common methods. These methods included Gaussian fitting, single logistic function fitting, double logistic function fitting, and smoothing techniques combined with fixed threshold and derivative-based determination approaches. There was no consistent interannual trend in either plant phenology or environmental factors at the two sites. Among the three types of plant phenology, a similar interannual pattern in the start of the growing season (SOS) was observed, whereas the interannual patterns for the end of the growing season (EOS) and the growing season length (GSL) were asynchronous. Compared to Phe_plant, both Phe_NDVI and Phe_GPP exhibited an earlier SOS, a delayed EOS, and consequently an extended GSL. The SOS derived from both Phe_NDVI and Phe_GPP was advanced by increasing spring temperatures at both sites, while the relationship between EOS and air temperature was relatively weak. The discrepancy between Phe_NDVI and Phe_GPP was more pronounced at CBF than at HBS, likely due to the complex vegetation composition and structure of the mixed forest. The different extraction methods produced more consistent and less variable estimates of SOS compared to EOS and GSL at both sites. Among the five methods, the dynamic threshold approach showed a relatively small difference between Phe_NDVI and Phe_GPP, suggesting that it could provide a more consistent estimate of plant phenology across the two sites. This study clearly reveals the inherent discrepancies associated with using different types of phenological data and the influence of extraction methods on phenology across different plant functional types. More attention should be given to improving the accuracy of EOS and understanding the influence of vegetation composition on phenological variation in future studies. Full article

Shrub communities play an irreplaceable role in maintaining ecological security in the stressed habitat areas of Northwest China. In these areas, multiple types of shrublands coexist simultaneously. Their diversity levels and community assembly processes may perform different patterns along different stress gradients. This study using linear model fitting, principal component analysis, analyzed the species and phylogenetic diversity of desert, alpine, and secondary shrublands along the gradients of environmental stress factors such as topography, soil, and climate, which reflect low temperature, human disturbance, and drought stress habitats. The changing trend of the phylogenetic structure of different types of shrublands was also studied with using variance decomposition, and phylogenetic structure analysis, which reveals their diversity maintenance mechanisms along environmental stress gradients. The research shows that (1) the mean annual temperature is the main environmental factor shaping the diversity patterns and maintenance processes of shrub communities because low temperatures may lead to habitat filtering; (2) in the western Loess Plateau, the community assembly of different types of shrublands is dominated by deterministic processes, but the diversity and assembly patterns of different shrublands are inconsistent across different environmental stress gradients. Systematic research on the diversity characteristics and assembly patterns of different shrub communities is of great significance for clarifying the restoration, succession, and stability of stressed habitat areas. Full article

As apex predators, wolves (Canis lupus) play a vital role in balancing and stabilizing ecosystems. However, the scarcity of empirical data on the population size and spatial ecology of wolves in Qinghai Province, China, poses significant challenges to the design of targeted conservation measures, with cascading effects on both regional ecosystem integrity and the long-term viability of this ecologically critical species. To address this knowledge gap, we deployed a systematic grid of 150 camera traps across Dulan County, Qinghai Province, from July 2021 to July 2022. The survey effort totaled 41,610 camera-days, yielding 392 independent wolf detections, defined as events separated by ≥24 h at the same location. The random encounter model estimated wolf density across three habitat types in Dulan County as follows: alpine meadows (4.87 ± 0.87 individuals/100 km²), bare rock areas (21.39 ± 3.79 individuals/100 km²), and alpine shrub (7.81 ± 1.31 individuals/100 km²). Wolves exhibited significant habitat selection (χ² = 23.6, p < 0.001), with 78% of detections occurring in alpine meadows and bare rocks at elevations of 4200–4300 m. The total wolf population was estimated to range from 2137 to 9169 individuals. Kernel density estimation (KDE) revealed a diurnal activity rhythm in wolves with minimal seasonal variation (Δ₄ = 0.88). Peak activity intensity occurred between 8:00 and 15:00, and 17:00 and 21:00, during the cold season, and between 10:00 and 15:00, and 18:00–22:00, in the warm season. The study provides a scientific basis for more effective management and conservation, enhancing understanding of wolf populations in Qinghai and peripheral regions. Full article

In alpine ecosystems, where low temperatures predominate, prostrate growth forms play a crucial role in thermal resistance by enabling thermal decoupling from ambient conditions, thereby creating a warmer microclimate. However, this strategy may be maladaptive during frequent heatwaves driven by climate change. This study combined microclimatic and plant characterization, infrared thermal imaging, and leaf photoinactivation to evaluate how thermal decoupling (TD) affects heat resistance (LT₅₀) in six alpine species from the Nevados de Chillán volcano complex in the Andes of south-central Chile. Results showed that plants’ temperatures increased with solar radiation, air, and soil temperatures, but decreased with increasing humidity. Most species exhibited negative TD, remaining 6.7 K cooler than the air temperature, with variation across species, time of day, and growth form; shorter, rounded plants showed stronger negative TD. Notably, despite negative TD, all species exhibited high heat resistance (Mean LT₅₀ = 46 °C), with LT₅₀ positively correlated with TD in shrubs. These findings highlight the intricate relationships between thermal decoupling, environmental factors, and plant traits in shaping heat resistance. This study provides insights into how alpine plants may respond to the increasing heat stress associated with climate change, emphasizing the adaptive significance of thermal decoupling in these environments. Full article

The rhizosphere serves as a critical interface for plant–soil–microorganism interactions. Rhizosphere soil refers to the soil directly adhering to root surfaces, while non-rhizosphere soil denotes the surrounding soil not in direct contact with roots. This study investigated the characteristics of soil microbial community structure, diversity, and enzyme activity dynamics in both rhizosphere and non-rhizosphere soils of Salix cupularis (shrub) across different restoration periods (4, 8, 16, and 24 years) in alpine sandy lands on the eastern Qinghai–Tibet Plateau, with unrestored sandy land as control (CK), while analyzing relationships between soil properties and microbial characteristics. Results demonstrated that with increasing restoration duration, activities of sucrase, urease, alkaline phosphatase, and catalase in Salix cupularis rhizosphere showed increasing trends across periods, with rhizosphere enzyme activities consistently exceeding non-rhizosphere levels. Bacterial Chao1 and Shannon indices followed similar patterns to enzyme activities, revealing statistically significant differences between rhizosphere and non-rhizosphere soils after 8 and 24 years of restoration, respectively. Dominant bacterial phyla ranked by relative abundance were Actinobacteria > Proteobacteria > Acidobacteria > Chloroflexi > Gemmatimonadetes. The relative abundance of Actinobacteria exhibited highly significant positive correlations with carbon, nitrogen, phosphorus, and enzyme activity indicators, indicating that Salix cupularis restoration promoted improvements in soil physicochemical properties and nutrient accumulation, thereby enhancing bacterial community diversity and increasing Actinobacteria abundance. These findings provide fundamental data for restoration ecology and microbial ecology in alpine ecosystems, offering a scientific basis for optimizing ecological restoration processes and improving recovery efficiency in alpine sandy ecosystems. Full article

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. Full article

Understanding rainfall partitioning by shrub canopies is essential for assessing water balance and improving hydrological models in cold regions. From 2010 to 2012, field experiments were conducted in the Hulu catchment of the Qilian Mountains, focusing on Potentilla fruticosa and Caragana jubata during the growing season. Throughfall, stemflow, and interception loss were measured using rain gauges, stemflow collars, and a water balance approach. A total of 197 natural rainfall events were recorded, and precipitation partitioning characteristics were analyzed in relation to rainfall intensity, amount, and vegetation traits. One-way ANOVA and regression analyses were used to test differences and correlations. The results showed that the critical rainfall threshold for generating throughfall and stemflow was 1.9 mm. For P. fruticosa, throughfall, stemflow, and interception loss accounted for 66.96%, 3.51%, and 29.53% of gross rainfall, respectively; the corresponding values for C. jubata were 67.31%, 7.27%, and 25.42%. Significant differences (p < 0.05) in stemflow were observed between species. Partitioning components were positively correlated with rainfall amount and stabilized at ~4 mm h⁻¹ intensity. Interception loss percentage decreased with intensity and plateaued at 2 mm h⁻¹ for P. fruticosa and 5 mm h⁻¹ for C. jubata. These findings provide empirical evidence for modeling shrub canopy rainfall redistribution in alpine environments. Full article

Afforestation is regarded as a crucial approach to enhancing terrestrial carbon sinks. Nevertheless, in ecologically fragile regions, the impacts of afforestation on carbon in biomass and soil remain highly uncertain. This study employed field investigations to explore the effects of forestry ecological projects on carbon stocks in biomass and soil within the Qinghai–Tibet Plateau, and to deeply analyze its key influencing factors. The key findings are summarized as follows: (1) The total vegetation carbon stocks of arbor forests and shrub forests (ranging from 7.7 to 24.0 Mg/ha) are 1.3–6.8 times that of grasslands (ranging from 3.5 to 6.1 Mg/ha). Afforestation-induced changes in biomass carbon are primarily attributed to the increase in carbon storage within the arbor-shrub layer, while exhibiting negligible effects on herbaceous layer carbon. (2) The soil organic carbon (SOC) stocks (0–100 cm depth) of forestland, shrubland, and grassland are 39.6–64.5 Mg/ha, 40.7–100.2 Mg/ha, and 43.1–121.9 Mg/ha, respectively. There are no significant differences in SOC stocks among shrubland, forestland, and grassland at either the 10- or 25-year development stage. The SOC stocks of 40-year-old shrubland and forestland are 1.5 and 2.3 times that of grassland, respectively. (3) For 10-year-old and 25-year-old arbor and shrub afforestation, biomass carbon increased while SOC decreased, showing a trade-off. In the case of 40- year-old afforestation, both biomass carbon and SOC increased synergistically. (4) Results from the random forest analysis indicate that the understory herbaceous diversity in this region has a significant impact on biomass carbon sequestration, and that soil total nitrogen, ammonium nitrogen, and nitrate nitrogen determine SOC sequestration. (5) Partial least squares analysis further demonstrates that afforestation promotes the retention of SOC stocks by increasing soil nutrients (especially nitrogen and nitrogen availability). Afforestation in alpine and arid regions, especially 40-year shrub afforestation, holds great carbon sequestration potential. The supplementation of soil nitrogen and phosphorus can enhance the carbon sequestration of this system. Full article

This paper focuses on insect remains found at the Kebezen site (51.93600° N, 87.09665° E) on the Turachak stream, Altai Republic, Russia, in layers ranging in age from 20.1 to 19.3 cal ky BP, corresponding to the onset of the last deglaciation. Coleoptera, represented by 105 species from 21 families, predominate in the sediments, with the families Carabidae, Staphylinidae, Chrysomelidae and Scolytidae being the most numerous. The insect assemblage of Kebezen contrasts sharply with the Late Pleistocene entomofauna of the West Siberian Plain, but it is similar with the assemblages of the geographically close Lebed site (Oldest and Older Dryas). Also, it corresponds well with the modern middle-altitude entomofauna of the mountains of north-eastern Altai. Based on such entomological data, boreal forests with a predominance of Picea and alpine meadows, as well as a cold and humid climate, were reconstructed for the Kebezen site. Changes in the ecological composition of beetles were traced during sedimentation: the most complete spectrum of the basal layer was replaced by a complex with a significant predominance of meadow and water-edge species, after which the proportions of shrub species, bryophilous species, and forest species consistently increased. Such changes correspond to the course of primary succession initiated by a catastrophic factor such as a megaflood. Full article

Understanding soil fertility is significant for the restoration and scientific management of shrub vegetation in the Qilian Mountains. This study focused on the soils associated with five common alpine shrub species—Salix gilashanica, Potentilla fruticosa, Caragana jubata, Caragana tangutica, and Berberis diaphana. We examined soil fertility characteristics, analyzed the relationships among soil fertility indicators, and evaluated the comprehensive fertility status of soil within shrub communities using principal component analysis. The results indicated that (1) the mean values of soil organic matter, total nitrogen, and total phosphorus were 77.94, 3.85, and 0.74 g kg⁻¹, respectively; (2) the soil organic matter and total nitrogen content were significantly higher than the national averages, while the total phosphorus content was slightly lower; and (3) the soil pH and total potassium showed weak variability, the total phosphorus content exhibited moderate variability, and other nutrient indicators (including soil organic matter, total nitrogen, alkali-hydrolyzable nitrogen, available phosphorus, available potassium, soil bulk density, and soil water content) exhibited strong variability. Soil organic matter exhibited a significant positive correlation with total nitrogen, alkali-hydrolyzable nitrogen, and soil water content but negatively correlated with soil pH and bulk density. Total nitrogen was positively correlated with alkali-hydrolyzable nitrogen, available phosphorus, and soil water content but negatively correlated with soil pH and soil bulk density. Total phosphorus demonstrated a positive correlation with total potassium and soil bulk density, whereas total potassium was negatively correlated with available phosphorus. The order of soil fertility of the five communities was Salix gilashanica > Potentilla fruticosa > Berberis diaphana > Caragana jubata > Caragana tangutica. The soil fertility index, based on PCA, indicated that Salix gilashanica exhibited the highest fertility status. The findings of this study provide a theoretical reference for the restoration and reconstruction of shrub vegetation, the enhancement of soil fertility, and the improvement of fragile ecosystems in the Qilian Mountains. It also provides essential insights for soil restoration and sustainable ecosystem management in alpine environments. Full article

Untangling the multiple drivers that affect biodiversity along elevation gradients is crucial for predicting the consequences of climate change on mountain ecosystems. However, the distribution patterns of microorganisms along elevation gradients have not yet been clarified, in particular when associated with strong changes in dominant species. Five typical vegetation types (i.e., coniferous forests, meadow grasslands, alpine shrubs, alpine meadows, and sparse vegetation of limestone flats) from contrasting vegetation belts were selected to explore the influence of elevation gradients on soil microbial communities. The results showed that Actinobacteriota and Proteobacteria were the dominant bacterial phyla. Ascomycota and Basidiomycota were the prevalent fungal phyla. Soil bacterial alpha diversity increased with increasing elevation, while soil fungal alpha diversity showed an obvious mid-elevation pattern. The beta diversity of the bacterial and fungal communities reflected a clear spatial niche-differentiation, and indicated that herbaceous plants affected soil bacterial communities while shrubs preferred soil fungal communities. A correlation analysis showed that environmental factors had different contributions to the composition and diversity of soil microbial communities. Soil bacteria were primarily affected by soil properties, whereas fungi were affected by vegetation. The research results can improve the prediction of soil microbial ecological processes and patterns related to elevation, and provide a theoretical basis for maintaining the sustainable development of soil microbial biodiversity under the background of global change. Full article