Search Results (75)

In order to investigate the infection status of Cryptosporidium in O. curzoniae and B. grunniens in Zoige County, Sichuan Province, fecal samples from B. grunniens and gastrointestinal contents from captured O. curzoniae were collected between March and December 2023 from five townships (Dazhasi, Axi, Hongxing, Tangke, and Maixi). Genomic DNA was extracted, and nested PCR targeting the small subunit (SSU) rRNA gene of Cryptosporidium was performed. PCR-positive products were sequenced, trimmed, aligned, and subjected to phylogenetic analysis to determine species and genotypes. A total of 242 samples were obtained, of which 20 were Cryptosporidium SSU rRNA-positive, yielding an overall detection rate of 8.3% (20/242). The detection rates of O. curzoniae and B. grunniens were 7.0% (8/114) and 9.4% (12/128), respectively. Among the five sampling sites, Maixi town exhibited the highest detection rate (32.4%, 11/44), followed by Hongxing town (15.2%, 7/46) and Tangke town (4.6%, 2/44). Phylogenetic analysis detected an unidentified Cryptosporidium sp. in O. curzoniae, while C. bovis (n = 10) and C. ryanae (n = 2) were detected in B. grunniens. These findings demonstrate that Cryptosporidium infections are present in both O. curzoniae and B. grunniens in Zoige County, with notable differences in infection rates and species composition. Continued surveillance of Cryptosporidium in local livestock and wildlife is warranted to provide critical data for regional public health management. Full article

Carbonaceous–siliceous–argillaceous rock-type uranium deposits, a major uranium resource in China, pose significant environmental risks due to heavy metal contamination. Geochemical investigations in the former Zoige uranium mine revealed elevated As, Cd, Cr, Cu, Ni, U, and Zn concentrations in soils and sediments, particularly at river confluences and downstream regions, attributed to leachate migration from ore bodies and tailings ponds. Surface samples exhibited high Cd bioavailability. The integrated BCR and mineral analysis reveals that Acid-soluble and reducible fractions of Ni, Cu, Zn, As, and Pb are governed by carbonate dissolution and Fe-Mn oxide dynamics via silicate weathering, while residual and oxidizable fractions show weak mineral-phase dependencies. Positive Matrix Factorization identified natural lithogenic, anthropogenic–natural composite, mining-related sources. Pollution assessments using geo-accumulation index and contamination factor demonstrated severe contamination disparities: soils showed extreme Cd pollution, moderate U, As, Zn contamination, and no Cr, Pb pollution (overall moderate risk); sediments exhibited extreme Cd pollution, moderate Ni, Zn, U levels, and negligible Cr, Pb impacts (overall extreme risk). USEPA health risk models indicated notable non-carcinogenic (higher in adults) and carcinogenic risks (higher in children) for both age groups. Ecological risk assessments categorized As, Cr, Cu, Ni, Pb, and Zn as low risk, contrasting with Cd (extremely high risk) and sediment-bound U (high risk). These findings underscore mining legacy as a critical environmental stressor and highlight the necessity for multi-source pollution mitigation strategies. Full article

Yak (Bos grunniens) meat is popular with a unique flavor and high nutritional value. This study investigated the effects of dietary supplementation with rumen-protected methionine (RPM) on meat quality, fatty acid composition, volatile flavor compounds, and transcriptomics of Longissimus lumborum of yak. Twenty-four male Maiwa yaks were selected and assigned to four groups: basal diet (CON), or supplementation of 5 g/d (RPM5), 10 g/d (RPM10), and 15 g/d (RPM15) RPM. The dose-dependent effects of RPM levels were evaluated through linear or quadratic trend analysis. The results showed that diet supplementation with RPM increased the intramuscular fat contents, improved composition of volatile flavor compounds and the ratio of monounsaturated fatty acids to saturated fatty acids. Compared to the CON group, there were 36, 84 and 23 up-regulated genes, and 85, 94 and 70 down-regulated genes in the RPM5, RPM10 and RPM15 groups, respectively. Gene ontology enrichment analysis revealed significant differentially expressed genes enrichment in biological processes, cellular components, and molecular functions across RPM5, RPM10, and RPM15 groups compared to the CON. KEGG pathway analysis revealed 99, 169, and 104 enriched pathways in RPM5, RPM10, and RPM15 groups, respectively. In summary, the addition of RPM to diets may provide new ideas and methods to improve meat quality of yaks. Full article

The production of artificial planted forage is important for the development of animal husbandry in the Qinghai–-Tibet Plateau, and oat forage is one of the main artificial planted forages in the area. However, the suitable oat varieties for harvesting and preparing silage feed in this region are still unclear. To investigate suitable oat forage varieties for silage production and the potential feeding value of different oat forage varieties, 16 oat forage varieties planted in Qinghai Province were selected in this experiment. These oat forages were subjected to two treatments: a group with no inoculants (CK) and a group with self-selected lactic acid bacteria (LAB) inoculants (IN). After 90 days of ensiling, silage quality and in vitro digestibility of the 16 oat forage varieties were determined. The results showed that all oat forage varieties ferment well after ensiling (pH < 4), the CK group had a silage pH range of 3.62–3.95, and the IN group had a silage pH range of 3.68–3.83. Tianyan No.1, Qingtian No.2, and Tianyan No.3 were in the top three in RFV and RFQ rankings in the CK group, while Qinghai 444, Tianyan No.1, and Tianyan No.3 were in the lead in GI rankings. Tianyan No.1, Qingtian No.2, and Everleaf 126 were in the lead in RFV and RFQ rankings in the IN group, while Qinghai 444, Titan, and Tianyan No.1 were in the top three in GI rankings. The dry matter digestibility and 72 h cumulative gas production of the IN group were higher than that of the CK group (p < 0.05). Based on principal component analysis and membership function comprehensive evaluation, Tianyan No.1, Qinghai 444, and Tianyan No.3 ranked the top three, demonstrating that these three oat forage varieties are suitable for silage processing in the Qinghai–Tibet Plateau region. Full article

Soil aggregate stability and carbon–nitrogen content are critical indicators for assessing the vegetation restoration effects. Salix cupularis plays a vital role in rehabilitating desertified alpine meadows on the eastern Qinghai–Tibet Plateau. However, research remains limited about how afforestation influences the soil aggregate stability and associated carbon and nitrogen dynamics. In this study, sandy land (0 years) served as the control, and the spatial time replacement method was used to examine changes in the soil water-stable aggregate composition, stability, organic carbon (OC) and total nitrogen (TN) contents, and density at a 0–60 cm depth after 5 and 10 years of afforestation restoration (Salix cupularis). Ecological restoration significantly enhanced the proportion of macroaggregates (>0.25 mm) in the topsoil (0–20 cm), and improved aggregate stability. After 10 years of restoration, macroaggregates increased by 45.04% and 51.32%, respectively. The average weight diameter and geometric mean diameter of the aggregates increased by 51.32% and 59.53%, respectively. Following restoration, there was a gradual increase in the OC and TN contents in the soil, with the highest increase observed in the 0–10 cm layer (266.67% and 391.67%). The OC and TN of the aggregates also displayed a similar trend. Correlation analysis results indicated a significant positive relationship between the soil OC and TN contents and density, OC content in aggregates of various diameters, and the stability of these aggregates. The Pearson’s correlation coefficient for OC in aggregates > 1 mm was the highest. Compared with 5 years, 10 years of recovery were more conducive to the formation of macroaggregates, enhancement in aggregate stability, and the accumulation of OC and TN. Therefore, vegetation restoration on the Zoige Plateau can significantly enhance the soil water-stable aggregate composition and stability and can also increase the soil and OC and TN contents and density, thereby enhancing the soil ecological quality. This study provides fundamental data and theoretical support for rehabilitating desertified grasslands on the eastern Qinghai–Tibet Plateau. Full article

Evapotranspiration (ET) is an important link between the water and energy cycles and directly determines the amount of available regional water resources. The Zoige forest–grass transition zone is a critical water conservation area in the upper reaches of the Yellow River, with high environmental heterogeneity, significant edge effects, and ecological and climatic gradient effects. The changing characteristics and influencing factors of evapotranspiration and its components in the region remain largely unknown. In this paper, the spatial and temporal evolution of evapotranspiration and its components in the Zoige forest–grass transition zone from 2003 to 2021 was investigated using the MOD16-STM ET algorithm, and the effects of environmental factors were analyzed. The results show that the MOD16-STM ET algorithm has good applicability in the Zoige forest–grass transition zone, and its coefficients of determination are 0.85 and 0.90 at the Zoige and Maqu stations, respectively. Vegetation transpiration accounts for 82% of the total evapotranspiration. ET is strongly influenced by the dynamics of the forest and grassland areas. The spatial distribution of evapotranspiration in the region varies considerably, with the forested areas in the east being larger than the grasslands and wetlands. Temperature and vegetation cover are the two most dominant contributors to ET changes among all the model drivers. Among the external environmental factors, altitude, maximum temperature, and minimum temperature are the dominant factors in the variation of ET in the region, and the interactions between the factors have a greater effect on ET than the individual factors. The findings provide a reference to investigate the spatial and temporal pattern of evapotranspiration and its components and the water cycle process in the Zoige forest–grass transition zone. Full article

Net ecosystem productivity (NEP) is a crucial metric for quantifying carbon storage, exchange, and cycling across global atmospheric and terrestrial ecosystems. This study examines the spatiotemporal patterns of NEP in China’s Zoigê alpine grassland and its response to climate variability, phenological changes, and soil conditions from 2000 to 2020. The results show a statistically significant increase in the annual NEP of the Zoigê Plateau, with an average rate of 3.18 g C/m²/year. Spatially, NEP displays strong heterogeneity, with higher values in the southwestern and northeastern marginal areas (>80 g C/m²) and lower values in the central region (<0 g C/m²). In alpine meadows (standardized total effect coefficient [STEC] = 0.52) and alpine steppes (STEC = 0.43), NEP is primarily regulated by soil moisture modulation, influenced by both water and temperature factors. This study accurately assesses NEP by incorporating regional soil characteristics, providing a more precise evaluation of changes in vegetation carbon sink sources in high-altitude areas. Full article

Water isotope studies in alpine wetlands have revealed the dynamic characteristics of the hydrological cycle and evapotranspiration processes in the Zoige region through hydrogen and oxygen isotope ratios. However, the hydrological continuity between marshes, rivers, and lakes in wetlands is relatively understudied. The study found that the Zoige Alpine Wetland local meteoric water line (LMWL) is δD = 8.33δ¹⁸O + 14.52 (R² = 0.92) by using linear regression analysis to confirm the Craig temperature effect equation backwards. Comparison with the global and Chinese LMWLs revealed that the slope of the Zoige LMWL is significantly higher than those of the global and Chinese LMWLs, indicating that the oceanic warm and humid airflow and the southwest monsoon significantly influence this region. The δ¹⁸O ranges of rivers, lakes, and marshes in the Zoige wetland were −12.86‰ to −2.02‰, −12.9‰ to −2.22‰, and −15.47‰ to −7.07‰, respectively. In terms of δD, marshes had the lowest δD values, with a mean value of −89.58‰, while rivers and lakes had close δD values of about −72‰. Rivers had the most dramatic variation in d-excess values, ranging from −34.16‰ to 3.68‰, while marshes and lakes had more concentrated d-excess values, with particularly negative values in marshes. Regression analysis yielded a trend line of δD = 5.41δ¹⁸O − 29.57 for evaporation from the water bodies, further demonstrating the importance of evaporation effects in this region. By using the Rayleigh fractionation model and estimating the climatic conditions, we found that the lake water had the highest evaporation intensity (41%). Those of the river and marsh water were 40% and 36%, respectively. The results of this study provide new scientific insights into the hydrological connectivity, evaporation processes, and water source characteristics in the Zoige wetland. Future studies can shed more light on how climate change affects wetland hydrological systems and how they change over time and space. This will help to manage water resources in the region and protect the environment. Full article

Both Avena sativa and Avena nuda, which are highly valued for their use in food and fodder, demonstrate considerable potential in the management of saline-alkali soils. This study aimed to establish a foundation for the selection of salt-tolerant oat cultivars by assessing the impact of varying salt concentrations (0, 50, 100, 150, and 200 mmol L⁻¹) on agronomic traits, photosynthetic characteristics, physiological and biochemical properties, and leaf anatomical structures in both covered oat cultivars and naked oat cultivars. The measured parameters indicate the level of salt tolerance in Avena sativa and Avena nuda, which is influenced by both salt concentration and cultivar. Both Avena sativa and Avena nuda demonstrate strong adaptation to mild and moderate salt stress conditions. However, Avena sativa exhibits a significantly greater capacity to withstand severe salt stress compared to Avena nuda. Affinity function analysis ranked the cultivars’ salt tolerance as follows: ‘Qinghai 444’ > ‘Mengyan No. 1’ > ‘Baiyan No. 18’ > ‘Qingyin No. 3’. These results suggest that the selection of oat cultivars for salinity improvement should be tailored to the specific salinity levels present in different regions. Full article

Under climate change and human activities, ecosystem service (ES) research lacks systematic approaches and scientific depth. This study develops a comprehensive framework integrating advanced models to predict ESs, analyze interactions, identify key drivers, and assess spatial effects on the Zoigê Plateau. The results indicate the following: (1) From 2000 to 2020 and across three 2040 scenarios, water conservation (WC) improves, while carbon storage (CS) and habitat quality (HQ) decline, leading to overall ES degradation. Core ES areas face rising degradation risks from 9% to 29% under increasing environmental stress (SSP119 to SSP585). (2) ES importance follows HQ > CS > SC > WC, with bivariate interactions outperforming single-factor effects. Future scenarios show weakened interactions, correlating with higher ecological stress, indicating ES stability risks. (3) Land use (>40% explanatory power) is the primary driver, while urban expansion, slope, evapotranspiration, and precipitation contribute (6–12%). (4) ES drivers showed weak spatial patterns from 2000 to 2020 but became more stable under future scenarios, suggesting stronger environmental control. This study provides a methodological paradigm for ES analysis and supports ecological planning in alpine wetland–grassland regions. Full article

Water use efficiency (WUE) plays a pivotal role in connecting the carbon and water cycles and represents the amount of water used by plants or ecosystems to achieve carbon sequestration. The response of WUE to climate warming and its underlying mechanisms remain unclear. Here, we examined the effects of varying levels of warming on carbon fluxes, water fluxes, and WUE in an alpine peatland, with Blysmus sinocompressus and Carex secbrirostris as dominant species. Open-top chambers were utilized to simulate two levels of warming: low-level warming (TL) and high-level warming (TH). The carbon dioxide and water fluxes were monitored over a growing season (June to September). Gradient warming significantly decreased both gross primary productivity (GPP) and net ecosystem carbon exchange (NEE); GPP was 10.05% and 13.31% lower and NEE was 21.00% and 30.00% lower in the TL and TH treatments, respectively, than in the control. Warming had no significant effect on soil evaporation, and plant transpiration and evapotranspiration were 36.98% and 23.71% higher in the TL treatment than in the control, respectively; this led to decreases of 31.38% and 28.17% in canopy water use efficiency (WUEc) and ecosystem water use efficiency (WUEe), respectively. Plant transpiration was the main factor affecting both WUEe and WUEc in response to warming. The findings underscore the essential function of water fluxes in regulating WUE and enhance our understanding of carbon–water coupling mechanisms under climate change. Full article

The extensive peatlands of the Tibetan Plateau (TP) play a vital role in sustaining the global ecological balance. However, the distribution of peatlands across this region and the related environmental factors remain poorly understood. To address this issue, we created a high-resolution (10 m) map for peatland distribution in the TP region using 6146 Sentinel-1 and 23,730 Sentinel-2 images obtained through the Google Earth Engine platform in 2023. We employed a random forest algorithm that integrated spatiotemporal features with field training samples. The overall accuracy of the peatland distribution map produced is high, at 86.33%. According to the classification results, the total area of peatlands on the TP is 57,671.55 km², and they are predominantly located in the northeast and southwest, particularly in the Zoige Protected Area. The classification primarily relied on the NDVI, NDWI, and RVI, while the DVI and MNDWI were also used in peatland mapping. B11, B12, NDWI, RVI, NDVI, and slope are the most significant features for peatland mapping, while roughness, correlation, entropy, and ASM have relatively slight significance. The methodology and peatland map developed in this work will enhance the conservation and management of peatlands on the TP while informing policy decisions and supporting sustainable development assessments. Full article

Net primary productivity (NPP) is a key metric for evaluating ecosystem carbon sink capacity and defining vegetation. Despite extensive research on vegetation NPP, much relies on coarse spatial resolution data, which often overlooks regional spatial heterogeneity, causing inaccuracies in NPP estimates. Therefore, this study employed the improved CASA model, based on GF-SG and kNDVI methods, to estimate vegetation NPP at a 30 m spatial resolution on the Zoigê Plateau from 2001 to 2020. The effects of anthropogenic and climatic factors on NPP were quantified through residual and partial correlation analyses. These results indicated the following: (1) NDVI derived from the GF-SG fusion method aligns closely with Landsat NDVI (R² ≈ 0.9). When contrasted with using NDVI alone, incorporating kNDVI into the CASA model enhances NPP assessment accuracy. (2) Vegetation NPP on the Zoigê Plateau has fluctuated upward by 2.09 gC·m⁻²·a⁻¹ over the last two decades, with higher values centrally and lower at the edges. (3) Monthly partial correlation analysis indicates almost no temporal effects in NPP response to temperature (97.42%) but significant cumulative effects in response to precipitation (80.3%), with longer accumulation periods in the south. Annual analysis reveals that NPP correlates more strongly with temperature than precipitation. (4) NPP changes are jointly influenced by climate change (48.46%) and human activities (51.54%), with the latter being the dominant factor. This study deepens the understanding of NPP dynamics in the Zoigê Plateau and offers insights for estimating NPP at high spatial-temporal resolutions. Full article

Planting oat forage in fallow fields during winter and producing total mixed ration (TMR) silage can effectively address issues of land wastage and forage shortages while maintaining forage quality. This study used oats and common vetch grown in winter fields in southern China as base materials, with additives including corn flour, soybean meal, corn lees, cottonseed meal, and premixes to formulate mixed feeds with roughage-to-concentrate ratios of 75:25, 70:30, and 65:35 on a dry matter basis. TMR silage was inoculated with a customized mixed lactic acid bacteria (LAB) additive composed of Lactobacillus plantarum 160 (patent number ZL202210218695.5), Lactobacillus pentosus 260 (patent number ZL202210204293), and Lactobacillus buchneri 225 (patent number ZL202210204293), at a ratio of 2:1:1, with addition rates of 4 × 10⁶, 2 × 10⁶, and 2 × 10⁶ cfu/g, respectively (IN), while sterile distilled water served as the control (CK). After a 60-day fermentation, the cornell net carbohydrate protein system (CNCPS) and in vitro digestion analysis were used to assess the effects of different roughage-to-concentrate ratios on the carbohydrate and protein components and ruminal degradation rate of fermented TMR (FTMR) silage, as well as to evaluate the impact of mixed LAB inoculation on FTMR nutritional quality, fermentation quality, and aerobic stability. The results indicated the following: (1) Regardless of the LAB addition, dry matter (DM), ether extract (EE), crude protein (CP), and Ash contents significantly decreased (p < 0.05) as the concentrate level decreased. In the IN group, as the concentrate level decreased, the water-soluble carbohydrate (WSC) content significantly increased (p < 0.05), the pH significantly decreased (p < 0.05), and the NH₃-N/TN significantly decreased (p < 0.05), with LAB counts significantly higher at a 65:35 roughage-to-concentrate ratio than in the other two groups. In the CK group, no significant changes (p > 0.05) were observed in the WSC content, pH, or LAB counts. (2) CNCPS analysis showed that in the IN group, the carbohydrate (CHO) content at a 75:25 roughage-to-concentrate ratio was significantly higher than in the other two groups (p < 0.05), while the non-utilizable carbohydrate (CC) content was significantly lower (p < 0.05). As the concentrate levels decreased, the non-protein nitrogen (PA) and moderately degradable true protein (PB2) content significantly increased (p < 0.05), whereas the rapidly degradable true protein (PB1) and slowly degradable true protein (PB3) content significantly decreased (p < 0.05). In the CK group, the CHO, PA, PB2, and PC content significantly increased (p < 0.05) as concentrate levels decreased, while the PB1 and PB3 content significantly decreased (p < 0.05). (3) In vitro digestibility characteristics indicated that gas production (GP) in the IN group was significantly lower than in the CK group (p < 0.05), with crude protein degradability increasing as concentrate levels decreased, regardless of the LAB addition. (4) At a 65:35 roughage-to-concentrate ratio, aerobic stability in the IN group was significantly higher than in the CK group (p < 0.05). In conclusion, higher concentrate ratios in total mixed rations (TMRs) with varying roughage-to-concentrate proportions improve the nutritional quality and promote the ruminal degradation of the FTMR. LAB inoculant addition could be an effective approach for addressing FTMR feed challenges. Full article

The control of flowering time plays an important role in the growth and development of potato tubers. The CCT (CO, COL and TOC1) gene family is involved in the flowering process of plants. In this study, a total of 32 StCCT family genes were identified and further classified into five subfamilies, including COL (17 members), PRR (4 members), ZIM (3 members), ASML2 (6 members) and TCR1 (2 members), based on their phylogenetic relationship. An analysis of the gene structure, motif compositions and conserved domain provided support for this classification. The StCCT genes were unevenly distributed on 12 chromosomes of the potato plant. In total, six gene duplication events were observed, which played a crucial role in the expansion of the StCCT family genes in the potato. The expression profiles exhibited diverse expression patterns of the StCCT genes in six tissues (leaf, shoot, root, tuber, stolon, and flower), StCCT32 is only expressed in flowers, while StCCT19 and StCCT8 are highly expressed in flowers and tubers, respectively. The StCCT genes exhibit different expression patterns in response to IAA and TIBA treatments at different concentrations across three tissues (leaf, stem, and tuber). After IAA and TIBA treatments, it was found that the expression level of StCCT7 was low in leaves and stems but significantly increased in tubers. Collectively, this study provided valuable information for the further study of potato formation and development and provided candidate genes for molecular breeding in the potato. Full article