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1.
Plants (Basel) ; 13(3)2024 Jan 23.
Artigo em Inglês | MEDLINE | ID: mdl-38337876

RESUMO

Anthropogenic nutrient additions are influencing the structure and function of alpine grassland ecosystems. However, the underlying mechanisms of the direct and indirect effects of nutrient additions on aboveground net primary productivity (ANPP) are not well understood. In this study, we conducted an eight-year field experiment to explore the ecological consequences of nitrogen (N) and/or phosphorous (P) additions on the northern Tibetan Plateau. ANPP, species diversity, functional diversity, and functional groups were used to assess species' responses to increasing nutrients. Our results showed that nutrient additions significantly increased ANPP due to the release in nutrient limitations. Although N addition had a significant effect on species richness and functional richness, and P and N + P additions altered functional diversity, it was functional groups rather than biodiversity that drove changes in ANPP in the indirect pathways. We identified the important roles of N and P additions in begetting the dominance of grasses and forbs, respectively. The study highlights that the shift of functional groups should be taken into consideration to better predict the structure, function, and biodiversity-ANPP relationship in grasslands, particularly under future multifaceted global change.

3.
Environ Pollut ; 337: 122562, 2023 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-37717896

RESUMO

The electroplating industry encompasses various processes and plating types that contribute to environmental pollution, which has led to growing public concern. To investigate related soil pollution in China, the study selected 10 sites with diverse industrial characteristics distributed across China and collected 1052 soil samples to determine the presence of industrial priority pollutants (PP) based on production process and pollutant toxicity. The factors influencing site pollution as well as proposed pollution prevention and control approaches were then evaluated. The results indicate the presence of significant pollution in the electroplating industry, with ten constituents surpassing the risk screening values (RSV). The identified PP consist of Cr(VI), zinc (Zn), nickel (Ni), total chromium (Cr), and petroleum hydrocarbons (C10-C40). PP contamination was primarily observed in production areas, liquid storage facilities, and solid zones. The vertical distribution of metal pollutants decreased with soil depth, whereas the reverse was true for petroleum hydrocarbons (C10-C40). Increase in site production time was strongly correlated with soil pollution, but strengthening anti-seepage measures in key areas can effectively reduce the soil exceedance standard ratio. This study serves as a foundation for conceptualizing site repair technology in the electroplating industry and offers a reference and methodology for pollution and source control in this and related sectors.


Assuntos
Poluentes Ambientais , Metais Pesados , Petróleo , Poluentes do Solo , Metais Pesados/análise , Galvanoplastia , Poluentes do Solo/análise , Medição de Risco , Monitoramento Ambiental/métodos , Poluição Ambiental/análise , Poluentes Ambientais/análise , Cromo/análise , Solo , China , Hidrocarbonetos/análise , Petróleo/análise
4.
Ecology ; 104(11): e4167, 2023 11.
Artigo em Inglês | MEDLINE | ID: mdl-37671849

RESUMO

Anthropogenic environmental changes are influencing the structure and function of many ecological communities, but their underlying mechanisms are often poorly understood. We conducted a 7-year field experiment to explore the ecological consequences of nitrogen (N) and phosphorous (P) enrichment in a high-altitude Tibetan alpine grassland. We found that the enrichment of both N and P, but not either alone, increased plant above- and belowground biomass. In contrast, N, but not P, enrichment reduced species richness and altered plant phylogenetic diversity and structure. Whereas plant species loss and changes in phylogenetic structure were mainly driven by higher soil manganese levels under N addition, they were mainly driven by increased plant belowground biomass under the addition of both N and P. Our study highlights the resource co-limitation of community biomass but not the structure of the study grassland, while also identifying soil metal toxicity and belowground competition as important mechanisms driving community changes following nutrient amendment.


Assuntos
Pradaria , Plantas , Biomassa , Filogenia , Solo/química , Nitrogênio/análise , Ecossistema
5.
Environ Res ; 227: 115700, 2023 06 15.
Artigo em Inglês | MEDLINE | ID: mdl-36931375

RESUMO

The existing method to survey site pollution is generally based on soil-groundwater sampling and instrumental analysis, which enables us to access the detailed soil pollution status while lacking quantitative association with industrial activities. It is urgent to understand contaminant discharge modes and establish a discharge inventory for achieving process-targeted pollution control. This study took a 40-year phosphate fertilizer-sulfuric acid site as an example and constructed a contaminant tracing method based on on-site investigations and detailed industrial data. These investigations and data were combined to determine the characteristic pollutant of this site, arsenic. And the calculation process of four-pathway pollution modes (atmospheric deposition, wastewater, solid waste leaching, and storage dripping) is derived from the existing acceptance criteria and risk assessment guidelines. They are set to calculate the arsenic's factory-to-soil discharge flux. The absent process contaminant release information and parameters, such as discharge coefficient, were obtained from soil-groundwater pollution control standards and discharge handbooks. It was found that the high concentration of arsenic (around 1930 mg g-1) was preponderantly caused by sulfur-iron slag and tailing leaching (96.19%), while the other pathways accounted for only 0.13% (atmospheric deposition), 3.59% (wastewater) and 0.09% (storage tank). Results were verified by the measured arsenic concentration, and the difference was +16.29%, which was acceptable. Finally, a contaminant discharge inventory was established with high-resolution spatial distribution and time-scale (historical discharge) evolution. The innovation of this study lies in the preliminary construction of a method for formulating soil discharge inventory. This study would contribute to the refined management of site pollution and reduction of source contaminants discharge. In addition, it will help infer the pollution condition of sites that are difficult to sample so as to help the government achieve precise source control.


Assuntos
Arsênio , Poluentes Ambientais , Poluentes do Solo , Arsênio/análise , Solo , Águas Residuárias , Poluição Ambiental/análise , Poluentes Ambientais/análise , Poluentes do Solo/análise , Monitoramento Ambiental/métodos
6.
Sci Total Environ ; 876: 162641, 2023 Jun 10.
Artigo em Inglês | MEDLINE | ID: mdl-36921851

RESUMO

Fostering crop-livestock integration via crop-forage rotation provides opportunities to cope with land degradation, feed deficit, and agropastoral sustainability. Farmers' preferences for forage options are influenced by economic benefit, environmental preference, and productive performance. However, there is little information available on evaluating multiple trade-offs of forage systems for the design of crop-forage rotations. Here, we performed a comprehensive evaluation to compare the economic, environmental, and productive indicators of five typical forage systems in terms of habitat conditions, soil ecosystem services, economic profit, and forage yield and nutritive value on the southern Tibetan Plateau. Alfalfa pasture and silage corn were mostly cultivated in lower altitudes, with more abundant precipitation, and higher growing degree days. Soil carbon and nitrogen accumulation were significantly higher in perennial alfalfa than in the other forage systems. The relative feed value of alfalfa pasture was also evidently greater than the other forage systems, whereas the yield of silage corn was among the highest. Alfalfa pasture presented superior economic benefits compared to the others. But the alfalfa pasture over six years showed a significant decrease in soil carbon and nitrogen storage, net present value, and yield. Forage systems generally have more soil carbon accumulation, but only forage legumes are more likely to positively affect soil nitrogen retention compared to cereal croplands. The trade-offs among economic, environmental, and productive indicators demonstrated that annual forage systems (silage corn, forage oat, and ryegrass) met productive target rather than environmental and economic objectives, while perennial alfalfa showed synergies among the three goals. These findings indicate that integrating crop-forage rotation, particularly introducing legume forages into farming systems is an adaptive option for crop-livestock integration on the southern Tibetan Plateau. Given the large topographic variation, suitable crop-forage systems should be designed for the heterogeneous Yarlung Zangbo River valleys. Among them, alfalfa-silage corn intercropping is recommended as a promising system to meet both productivity and profitability.


Assuntos
Ecossistema , Gado , Animais , Indicadores Ambientais , Tibet , Solo , Zea mays , Medicago sativa , Carbono , Nitrogênio
7.
Sci Total Environ ; 857(Pt 1): 159390, 2023 Jan 20.
Artigo em Inglês | MEDLINE | ID: mdl-36243072

RESUMO

Annual gross primary productivity (AGPP) is the basis for grain production and terrestrial carbon sequestration. Mapping regional AGPP from site measurements provides methodological support for analysing AGPP spatiotemporal variations thereby ensures regional food security and mitigates climate change. Based on 641 site-year eddy covariance measuring AGPP from China, we built an AGPP mapping scheme based on its formation and selected the optimal mapping way, which was conducted through analysing the predicting performances of divergent mapping tools, variable combinations, and mapping approaches in predicting observed AGPP variations. The reasonability of the selected optimal scheme was confirmed by assessing the consistency between its generating AGPP and previous products in spatiotemporal variations and total amount. Random forest regression tree explained 85 % of observed AGPP variations, outperforming other machine learning algorithms and classical statistical methods. Variable combinations containing climate, soil, and biological factors showed superior performance to other variable combinations. Mapping AGPP through predicting AGPP per leaf area (PAGPP) explained 86 % of AGPP variations, which was superior to other approaches. The optimal scheme was thus using a random forest regression tree, combining climate, soil, and biological variables, and predicting PAGPP. The optimal scheme generating AGPP of Chinese terrestrial ecosystems decreased from southeast to northwest, which was highly consistent with previous products. The interannual trend and interannual variation of our generating AGPP showed a decreasing trend from east to west and from southeast to northwest, respectively, which was consistent with data-oriented products. The mean total amount of generated AGPP was 7.03 ± 0.45 PgC yr-1 falling into the range of previous works. Considering the consistency between the generated AGPP and previous products, our optimal mapping way was suitable for mapping AGPP from site measurements. Our results provided a methodological support for mapping regional AGPP and other fluxes.


Assuntos
Mudança Climática , Ecossistema , Sequestro de Carbono , Solo , Aprendizado de Máquina , Carbono , Dióxido de Carbono/análise
8.
Lupus ; 32(2): 207-215, 2023 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-36470586

RESUMO

BACKGROUND: Self-disclosure may enhance positive illness perceptions, whereas patients with systemic lupus erythematosus (SLE) always facing negative illness perceptions due to multiple reasons, so elucidation of factors affecting self-disclosure may facilitate the development of quality of life. METHODS: A total of 161 hospitalized patients with SLE were recruited. Scales on demographic and clinical characteristics, self-disclosure, psychosocial status (e.g. Social Support Rating Scale - SSRS) and quality of life were used to collect related information from clients. Univariate analysis was performed by Kruskal-Wallis rank-sum test or chi-square test, and multivariate analysis by ordinal logistic regression. RESULTS: Social support, drinking, depression and cause of hospitalization were found to be influencing factors of self-disclosure. Multiple logistic regression analyses revealed that the significant and independent factors associated with self-disclosure in patients with SLE were social support, drinking and depression. Domains of LupusQoL, except physical health and fatigue, were positively correlated with self-disclosure. CONCLUSIONS: With the increase of social support, the level of self-disclosure become worse, drinking, depression and cause of hospitalization are risk factors for it. Moreover, the level of self-disclosure is positively related to the LupusQoL. Medical staff should formulate effective measures according to the results to improve self-disclosure in patients with SLE and promote their quality of life.


Assuntos
Lúpus Eritematoso Sistêmico , Qualidade de Vida , Humanos , Qualidade de Vida/psicologia , Revelação , Inquéritos e Questionários , Lúpus Eritematoso Sistêmico/complicações , Análise Multivariada , Índice de Gravidade de Doença
9.
Sci Total Environ ; 855: 158923, 2023 Jan 10.
Artigo em Inglês | MEDLINE | ID: mdl-36165909

RESUMO

Many recent studies have explored how global warming and increased nitrogen (N) deposition affect the structure and function of natural ecosystems. However, how ecosystems respond to the combination of warming and N enrichment remains unexplored, especially under asymmetric seasonal warming scenarios. We conducted a decade-long field experiment in an alpine grassland to investigate the effects of warming (ambient condition (NW), winter-only (WW), and year-round (YW) warming) and N addition on the temporal stability of communities. Although N addition significantly reduced community temporal stability in NW, WW, and YW, WW relieved the severely negative effects of N addition compared to NW and YW (from 47.7 % in NW and 76.1 % in YW to 18.6 % in WW under 80 kg N hm-2 year-1). The most remarkable finding is that the main factors driving community stability shifted with warming patterns. The increase in community dominance under NW was a significant driver of the decreased temporal stability in the community. However, the decrease in community stability caused by N addition was ascribed to the decreased stability of both dominant and common species under WW. In contrast, N addition decreased community temporal stability mainly via a decrease in species asynchrony under YW. Our results suggested that warming patterns can modulate the effects of N enhancement on community stability. To predict the effects of climate change on alpine grasslands accurately, the idiosyncratic effects of asymmetric seasonal warming under future climate change scenarios should be considered.


Assuntos
Ecossistema , Pradaria , Nitrogênio/análise , Estações do Ano , Tibet , Solo/química , Biomassa
10.
J Prof Nurs ; 43: 53-60, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-36496245

RESUMO

BACKGROUND: Previous studies have shown that empathy has a positive impact on the professional identity of nursing students. And developing psychological resilience can improve the professional identity of nursing students. However, studies investigating the mechanism of the relationship between empathy and psychological resilience on professional identity remain few. PURPOSE: Among Chinese nursing students, we sought to determine whether psychological resilience mediates the association between empathy and professional identity. METHODS: A total of 495 undergraduate and postgraduate nursing students in a medical university nursing college in Hefei were investigated by demographic data questionnaire, nursing students' empathy scale, nursing students' professional identity questionnaire, and psychological resilience questionnaire. Structural equation modeling was used to analyze the mediating effect of psychological resilience between empathy and the professional identity of nursing students. RESULTS: The total score of professional identity of nursing students was 57.07 ± 10.38. Psychological resilience (r = 0.316, P < 0.01) and professional identity (r = 0.313, P < 0.01) both had positive correlations with empathy, respectively. Additionally, there was a strong correlation between psychological resilience and professional identity (r = 0.488, P < 0.01). Empathy had an indirect effect on professional identity through psychological resilience, with a direct effect of 0.256 and an indirect effect of 0.145, and the indirect effect accounted for 36.16 % of the total effect. CONCLUSION: Nursing educators should pay attention to the cultivation of empathy ability and psychological resilience to enhance nursing students' professional identity.


Assuntos
Resiliência Psicológica , Estudantes de Enfermagem , Humanos , Estudantes de Enfermagem/psicologia , População do Leste Asiático , Estudos Transversais , Empatia , Inquéritos e Questionários
11.
Front Psychiatry ; 13: 893235, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35990077

RESUMO

The evidence on the relationship between social support and quality of life in female systemic lupus erythematosus (SLE) patients is complex. The purpose of this study was to explore the impacts of distress disclosure and anxiety on the association between social support and quality of life among Chinese women with SLE. A cross-sectional study was conducted, and 237 samples were obtained. Measures included demographic characteristics, Lupus Quality of Life (LupusQoL), social support rate scale (SSRS), distress disclosure index (DDI), and self-rating anxiety scale (SAS). Descriptive statistics, correlation analysis, and moderated mediating effect analysis were carried out. The LupusQoL was negatively correlated with age, systemic lupus erythematosus disease activity index (SLEDAI), DDI, and SAS. SSRS had a positive predictive effect on the LupusQoL, while SLEDAI and DDI had the opposite effect. SAS had a negative predictive effect on the LupusQoL. There were interactive effects of SAS and DDI on LupusQoL. In the moderated mediation model, SAS played moderating effect in the role of DDI on LupusQoL; the DDI of female patients with SLE played a partial mediator role, the mediation effect was 0.19, and the mediation effect ratio was 33.3%. In conclusion, to pay attention to the QOL, we should consider the mediator role of distress disclosure and the moderating role of anxiety.

12.
Sci Total Environ ; 838(Pt 3): 156512, 2022 Sep 10.
Artigo em Inglês | MEDLINE | ID: mdl-35679928

RESUMO

Identifying ecological strategies based on functional traits can help us better understand plants' adaptations and changes in ecological processes, and thus predict the impact of climate change on ecosystems, especially in the vulnerable alpine grasslands. Herein, we investigated the plant CSR strategies of four grassland types (alpine meadows, AM; alpine meadow steppes, AMS; alpine steppes, AS; and alpine desert steppes, ADS) and its functional groups (grasses, sedges, legumes, and forbs) along the east-to-west gradient of decreasing precipitation on the northern Tibetan grasslands by using Grime's CSR (C: competitor, S: stress tolerator, and R: ruderal) analysis. Although alpine grasslands were dominated by S-strategy, our results also indicated that AM with higher water, nitrogen (N) and phosphorus (P) availability had significantly lower S-strategy values and relatively higher C- and R-strategy values (C: S: R = 6: 63: 31 %) than those in AMS (C: S: R = 3: 94: 3 %,), AS (C: S: R = 3: 87: 10 %), and ADS (C: S: R = 1: 94: 5 %). The CSR strategy values of forbs and legumes showed greater variability compared with grasses and sedges in the environmental gradient. Furthermore, water variability on the precipitation gradient eventually affected plant traits and CSR strategies through soil N and P availability and pH. Our findings highlighted that plant CSR strategies were regulated by the availability of soil resources, and plants adopted more flexible adaptation strategies in relatively resource-rich environments. This study sheds light on the mechanisms of plant adaptation to the changing environment in the alpine grasslands.


Assuntos
Ecossistema , Pradaria , Plantas , Poaceae , Solo , Tibet , Água
13.
Sci Total Environ ; 838(Pt 2): 156150, 2022 Sep 10.
Artigo em Inglês | MEDLINE | ID: mdl-35613643

RESUMO

Biodiversity-stability mechanisms have been the focus of many long-term community stability studies. Community functional composition (i.e., functional diversity and functional identity of community plant functional traits) is critical for community stability; however, this topic has received less attention in large-scale studies. Here, we combined a field survey of biodiversity and plant functional traits in 22 alpine grassland sites throughout the northern Tibetan Plateau with 20 years of satellite-sensed proxy data (enhanced vegetation index) of community productivity to identify the factors influencing community stability. Our results showed that functional composition influenced community stability the most, explaining 61.71% of the variation in community stability (of which functional diversity explained 18.56% and functional identity explained 43.15%), which was a higher contribution than that of biodiversity (Berger-Parker index and species evenness; 35.04%). Structural equation modeling suggested that functional identity strongly affected community stability, whereas biodiversity had a minor impact. Furthermore, functional identity of leaf dry matter content regulated community stability by enhancing species dominance (Berger-Parker index). Our findings demonstrate that functional composition, specifically functional identity, plays a key role in community stability, highlighting the importance of functional identity in understanding and revealing the stabilizing mechanisms in these fragile alpine ecosystems which are subjected to increasing environmental fluctuations.


Assuntos
Ecossistema , Pradaria , Biodiversidade , Folhas de Planta , Plantas , Tibet
14.
Clin Rheumatol ; 41(9): 2713-2720, 2022 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-35536414

RESUMO

OBJECTIVE: To evaluate the reliability and validity of the Chinese version of the eight-item Morisky Medication Adherence Scale (MMAS-8) in Chinese patients with systemic lupus erythematosus (SLE). METHODS: The survey was conducted with a consecutive sampling of 158 Chinese SLE patients attending public hospitals from January to March 2021. We used the translated Chinese version of the MMAS-8 to collect related data. Reliability, item, and factor analyses were used to test the reliability and validity of the MMAS-8 scale in the selected patients. The internal consistency reliability was evaluated using Cronbach's α coefficient. Test-retest reliability was assessed using intraclass correlation coefficients (ICCs) in a subset of 30 participants. Construct validity was evaluated using confirmatory factor analysis and correlations between the Self-efficacy for Appropriate Medication Use Scale (SEAMS) and related measures. RESULTS: The internal consistency reliability of the Chinese version of the MMAS-8 was high (Cronbach's α = 0.817), and the test-retest reliability was excellent (intraclass correlation = 0.947; P < 0.001). There were significant differences in the F test and t test between the two extreme groups before and after the ranking of 27% of the questionnaire scores (P < 0.001). The Kaiser-Meyer-Olkin (KMO) value of construct validity was 0.860. The spherical test value of Bartlettgers was 417.8822. Factor analysis yielded three components that accounted for 69.375% of the total variance. Exploratory factor analysis identified three dimensions of the Chinese version of the MMAS-8. In terms of criterion validity, the correlation of the MMAS-8 score in SEAMS indicated that the convergent validity was good (r = 0.926; P < 0.001). CONCLUSIONS: This study shows that the Chinese version of the Medication Adherence Scale-8 is a reliable and valid tool for assessing medication adherence in Chinese SLE patients. Key Points • Many factors affect medication adherence in SLE patients. • Many questionnaires measure medication adherence levels. • There is a lack of reliable validation of medication adherence questionnaires specifically for SLE patients.


Assuntos
Lúpus Eritematoso Sistêmico , Adesão à Medicação , China , Humanos , Lúpus Eritematoso Sistêmico/tratamento farmacológico , Psicometria/métodos , Reprodutibilidade dos Testes , Inquéritos e Questionários
15.
Glob Chang Biol ; 28(11): 3651-3664, 2022 06.
Artigo em Inglês | MEDLINE | ID: mdl-35231142

RESUMO

Belowground plant traits play important roles in plant diversity loss driven by atmospheric nitrogen (N) deposition. However, the way N enrichment shapes plant microhabitats by patterning belowground traits and finally determines aboveground responses is poorly understood. Here, we investigated the rhizosheath trait of 74 plant species in seven N-addition simulation experiments across multiple grassland ecosystems in China. We found that rhizosheath formation differed among plant functional groups and contributed to changes in plant community composition induced by N enrichment. Compared with forb species, grass and sedge species exhibited distinct rhizosheaths; moreover, grasses and sedges expanded their rhizosheaths with increasing N-addition rate which allowed them to colonize belowground habitats. Grasses also shaped a different microenvironment around their roots compared with forbs by affecting the physicochemical, biological, and stress-avoiding properties of their rhizosphere soil. Rhizosheaths act as a "biofilm-like shield" by the accumulation of protective compounds, carboxylic anions and polysaccharides, determined by both plants and microorganisms. This enhanced the tolerance of grasses and sedges to stresses induced by N enrichment. Conversely, forbs lacked the protective rhizosheaths which renders their roots sensitive to stresses induced by N enrichment, thus contributing to their disappearance under N-enriched conditions. This study uncovers the processes by which belowground facilitation and trait matching affect aboveground responses under conditions of N enrichment, which advances our mechanistic understanding of the contribution of competitive exclusion and environmental tolerance to plant diversity loss caused by N deposition.


Assuntos
Pradaria , Nitrogênio , Biomassa , Ecossistema , Plantas , Poaceae , Solo/química
16.
Ecol Evol ; 11(19): 13259-13267, 2021 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-34646467

RESUMO

Although many empirical experiments have shown that increasing degradation results in lower aboveground biomass (AGB), our knowledge of the magnitude of belowground biomass (BGB) for individual plants is a prerequisite for accurately revealing the biomass trade-off in degraded grasslands. Here, by linking the AGB and BGB of individual plants, species in the community, and soil properties, we explored the biomass partitioning patterns in different plant functional groups (grasses of Stipa capillacea and forbs of Anaphalis xylorhiza). Our results indicated that 81% and 60% of the biomass trade-off variations could be explained by environmental factors affecting grasses and forbs, respectively. The change in community species diversity dominated the biomass trade-off via either direct or indirect effects on soil properties and biomass. However, the community species diversity imparted divergent effects on the biomass trade-off for grasses (scored at -0.72) and forbs (scored at 0.59). Our findings suggest that plant communities have evolved two contrasting strategies of biomass allocation patterns in degraded grasslands. These are the "conservative" strategy in grasses, in which plants with larger BGB trade-off depends on gigantic roots for soil resources, and the "opportunistic" strategy in forbs, in which plants can adapt to degraded lands using high variation and optimal biomass allocation.

17.
Sci Total Environ ; 800: 149572, 2021 Dec 15.
Artigo em Inglês | MEDLINE | ID: mdl-34392221

RESUMO

The replacement of dominant sedges/grasses with secondary forbs is common in alpine rangelands, but the underlying plant ecological strategies and their relevance to leaf traits and their variabilities of different plant functional groups remain largely unknown. Here, we measured key leaf traits and analyzed the competitor, stress-tolerator and ruderal (CSR) strategies of major species with different functional groups (sedges, grasses and forbs) in an alpine meadow along a degradation gradient on the Tibetan Plateau. Our results indicated that S-selected species were dominant in both non-degraded (C:S:R = 1:95:4%) and severely degraded (C:S:R = 2:87:11%) meadows. However, there was a shift from S- to R-strategy in the communities after rangeland degradation. More specifically, sedges and grasses with a "conservative" strategy maintained stronger S-strategy to tolerate degraded and stressful conditions. In contrast, forbs with an "opportunistic" strategy (increase 9.5% in R-score) tended to adapt to degraded stages. Moreover, 51.1% and 23.9% of the increased R-scores in forbs were accounted by leaf mass per area and specific leaf area, respectively. Generally, higher leaf water and nitrogen contents coupled with larger variations in leaf traits and flexible SR strategies in forbs enabled them to capitalize on lower soil water and nutrient availability. Our findings highlighted that the contrasting strategies of plant species in response to the decrease in available resources might lead to niche expansion of secondary forbs and loss of diversity in the degraded alpine meadow. The emerging alternative stable states in the degraded rangelands might bring about a predicament for rangeland restoration.


Assuntos
Pradaria , Plantas , Biomassa , Solo , Tibet
18.
Sci Total Environ ; 791: 148379, 2021 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-34412395

RESUMO

Alpine grasslands play important functions in mitigating climate change and regulating water resources. However, the spatiotemporal variability of their carbon and water budgets remains unquantified. Here, 47 site-year observations of CO2 and water vapor fluxes (ET) are analyzed at sites situated along a hydrothermal gradient across the Qinghai-Tibetan Plateau, including an alpine wetland (wettest), an alpine shrub (coldest), an alpine meadow, an alpine meadow-steppe, and an alpine steppe (driest and warmest). The results show that the benchmarks for annual net ecosystem exchange (NEE) are -79.3, -77.8, -66.7, 20.2, and 100.9 g C m-2 year-1 at the meadow, shrub, meadow-steppe, steppe, and wetland, respectively. The peak daily NEE normalized by peak leaf area index converges to 0.93 g C m-2 d-1 at the 5 sites. Except in the wetland (722.8 mm), the benchmarks of annual ET fluctuate from 511.0 mm in the steppe to 589.2 mm in the meadow. Boosted regression trees-based analysis suggests that the enhanced vegetation index (EVI) and net radiation (Rn) determine the variations of growing season monthly CO2 fluxes and ET, respectively, although the effect is to some extent site-specific. Inter-annual variability in NEE, ecosystem respiration (RES), and ET are tightly (R2 > 0.60) related to the inter-growing season NEE, RES, and ET, respectively. Both annual RES and annual NEE are significantly constrained by annual gross primary productivity (GPP), with 85% of the per-unit GPP contributing to RES (R2 = 0.84) and 15% to NEE (R2 = 0.12). Annual GPP significantly correlates with annual ET alone at the drier sites of the meadow-steppe and the steppe, suggesting the coupling of carbon and water is moisture-dependent in alpine grasslands. Over half of the inter-annual spatial variability in GPP, RES, NEE, and ET is explained by EVI, atmospheric water vapor, topsoil water content, and bulk surface resistance (rs), respectively. Because the spatial variations of EVI and rs are strongly regulated by atmospheric water vapor (R2 = 0.48) and topsoil water content (R2 = 0.54), respectively, we conclude that atmospheric water vapor and topsoil water content, rather than the expected air/soil temperatures, drive the spatiotemporal variations in CO2 fluxes and ET across temperature-limited grasslands. These findings are critical for improving predictions of the carbon sequestration and water holding capacity of alpine grasslands.


Assuntos
Pradaria , Solo , Dióxido de Carbono , Ecossistema , Vapor , Tibet
19.
Sci Adv ; 7(15)2021 04.
Artigo em Inglês | MEDLINE | ID: mdl-33837072

RESUMO

Warming-induced carbon loss through terrestrial ecosystem respiration (Re) is likely getting stronger in high latitudes and cold regions because of the more rapid warming and higher temperature sensitivity of Re (Q 10). However, it is not known whether the spatial relationship between Q 10 and temperature also holds temporally under a future warmer climate. Here, we analyzed apparent Q 10 values derived from multiyear observations at 74 FLUXNET sites spanning diverse climates and biomes. We found warming-induced decline in Q 10 is stronger at colder regions than other locations, which is consistent with a meta-analysis of 54 field warming experiments across the globe. We predict future warming will shrink the global variability of Q 10 values to an average of 1.44 across the globe under a high emission trajectory (RCP 8.5) by the end of the century. Therefore, warming-induced carbon loss may be less than previously assumed because of Q 10 homogenization in a warming world.

20.
Clin Rheumatol ; 40(3): 913-922, 2021 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-32748069

RESUMO

OBJECTIVES: To obtain a reliable estimation on the sleep quality in patients with systemic lupus erythematosus (SLE) and identify the main sleep problems, a meta-analysis was performed. METHODS: Up to March 21, 2020, PubMed, EMBASE, and Cochrane Library were searched; quality evaluation were conducted with Newcastle-Ottawa Scale; statistical analyses were performed by stata14.0 software; results were expressed by weighted mean difference or standardized mean difference (WMD/SMD) and 95% confidence interval (CI). RESULTS: Eighteen case-control studies were included in meta-analysis, 1086 SLE patients and 2866 controls were collected. The score of sleep quality in the case group was higher than that in the control group (SMD = 1.03, 95% CI: 0.80-1.27), and so was the Pittsburgh Sleep Quality Index (PSQI) (WMD = 3.45, 95% CI: 2.49-4.42). The first three complaints of sleep problems in PSQI were daytime dysfunction (WMD = 0.64, 95% CI: 0.36-0.92), subjective sleep quality (WMD = 0.62, 95% CI: 0.40-0.84), and habitual sleep efficiency (WMD = 0.54, 95% CI: 0.37-0.72). Subgroup analyses showed that the score of sleep quality in SLE patients were higher than controls among different regions, races, and disease duration. The sleep quality score of SLE patients with fibromyalgia (FM) was higher than that in general control, but no significant difference as compared with SLE patients without FM. CONCLUSIONS: Our meta-analysis indicates that the sleep quality of SLE patients is worse than that of the general population; thus, more attention should be paid to the sleep status among this disease. Key Points •The sleep quality of SLE patients is worse than that of the general population. •Region, race, and disease duration are correlated with sleep quality in SLE patients.


Assuntos
Fibromialgia , Lúpus Eritematoso Sistêmico , Estudos de Casos e Controles , Humanos , Lúpus Eritematoso Sistêmico/complicações , Sono
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