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1. chinaXiv:202206.00151 [pdf]

Dependency of litter decomposition on litter quality, climate change, and grassland type in the alpine grassland of Tianshan Mountains, Northwest China

SU Yuan; GONG Yanming; HAN Wenxuan; LI Kaihui; LIU Xuejun
Subjects: Biology >> Ecology

Abstract: Litter decomposition is an important component of the nutrient recycling process and is highly sensitive to climate change. However, the impacts of warming and increased precipitation on litter decomposition have not been well studied, especially in the alpine grassland of Tianshan Mountains. We conducted a manipulative warming and increased precipitation experiment combined with different grassland types to examine the impact of litter quality and climate change on the litter decomposition rate based on three dominant species (Astragalus mongholicus, Potentilla anserina, and Festuca ovina) in Tianshan Mountains from 2019 to 2021. The results of this study indicated there were significant differences in litter quality, specific leaf area, and leaf dry matter content. In addition, litter quality exerted significant effects on litter decomposition, and the litter decomposition rate varied in different grassland types. Increased precipitation significantly accelerated the litter decomposition of P. anserina; however, it had no significant effect on the litter decomposition of A. mongholicus and F. ovina. However, warming consistently decreased the litter decomposition rate, with the strongest impact on the litter decomposition of F. ovina. There was a significant interaction between increased precipitation and litter type, but there was no significant interaction between warming and litter type. These results indicated that warming and increased precipitation significantly influenced litter decomposition; however, the strength was dependent on litter quality. In addition, soil water content played a crucial role in regulating litter decomposition in different grassland types. Moreover, we found that the litter decomposition rate exhibited a hump-shaped or linear response to the increase of soil water content. Our study emphasizes that ongoing climate change significantly altered litter decomposition in the alpine grassland, which is of great significance for understanding the nutrient supply and turnover of litter.

submitted time 2022-06-17 Cooperative journals:《Journal of Arid Land》 Hits318Downloads183 Comment 0

2. chinaXiv:202206.00153 [pdf]

Water use characteristics of different pioneer shrubs at different ages in western Chinese Loess Plateau: Evidence from δ2H offset correction

ZHANG Yu; ZHANG Mingjun; QU Deye; WANG Shengjie; Athanassios A ARGIRIOU; WANG Jiaxin; YANG Ye
Subjects: Biology >> Ecology

Abstract: Caragana korshinskii Kom. and Tamarix ramosissima Ledeb. are pioneer shrubs for water and soil conservation, and for windbreak and sand fixation in arid and semi-arid areas. Understanding the water use characteristics of different pioneer shrubs at different ages is of great importance for their survival when extreme rainfall occurs. In recent years, the stable isotope tracing technique has been used in exploring the water use strategies of plants. However, the widespread δ2H offsets of stem water from its potential sources result in conflicting interpretations of water utilization of plants in arid and semi-arid areas. In this study, we used three sets of hydrogen and oxygen stable isotope data (δ2H and δ18O, corrected δ2H_c1 based on SW-excess and δ18O, and corrected δ2H_c2 based on −8.1‰ and δ18O) as inputs for the MixSIAR model to explore the water use characteristics of C. korshinskii and T. ramosissima at different ages and in response to rainfall. The results showed that δ2H_c1 and δ18O have the best performance, and the contribution rate of deep soil water was underestimated because of δ2H offset. During the dry periods, C. korshinskii and T. ramosissima at different ages both obtained mostly water from deeper soil layers. After rainfall, the proportions of surface (0–10 cm) and shallow (10–40 cm) soil water for C. korshinskii and T. ramosissima at different ages both increased. Nevertheless, there were different response mechanisms of these two plants for rainfall. In addition, C. korshinskii absorbed various potential water sources, while T. ramosissima only used deep water. These flexible water use characteristics of C. korshinskii and T. ramosissima might facilitate the coexistence of plants once extreme rainfall occurs. Thus, reasonable allocation of different plants may be a good vegetation restoration program in western Chinese Loess Plateau.

submitted time 2022-06-17 Cooperative journals:《Journal of Arid Land》 Hits312Downloads177 Comment 0

3. chinaXiv:202206.00155 [pdf]

Spatiotemporal variations and driving factors of habitat quality in the loess hilly area of the Yellow River Basin: A case study of Lanzhou City, China

DONG Jianhong; ZHANG Zhibin; LIU Benteng; ZHANG Xinhong; ZHANG Wenbin; CHEN Long
Subjects: Biology >> Ecology

Abstract: Rapid industrialization and urbanization have led to the most serious habitat degradation in China, especially in the loess hilly area of the Yellow River Basin, where the ecological environment is relatively fragile. The contradiction between economic development and ecological environment protection has aroused widespread concern. In this study, we used the habitat quality of Integrated Valuation of Ecosystem Services and Tradeoffs (InVEST-HQ) model at different scales to evaluate the dynamic evolution characteristics of habitat quality in Lanzhou City, Gansu Province of China. The spatiotemporal variations of habitat quality were analyzed by spatial autocorrelation. A Geographical Detector (Geodetector) model was used to explore the driving factors that influencing the spatial differentiation of habitat quality, including natural factors, socio-economic factors, and ecological protection factors. The results showed that the habitat quality index of Lanzhou City decreased from 0.4638 to 0.4548 during 2000–2018. The areas with reduced the habitat quality index were mainly located in the Yellow River Basin and Qinwangchuan Basin, where are the main urban areas and the new economic development areas, respectively. The spatial distribution of habitat quality presented a trend of high in the surrounding areas and low in the middle, and showed a significant positive spatial autocorrelation. With the increase of study scale, the spatial distribution of habitat quality changed from concentrated to dispersed. The spatial differentiation of habitat quality in the study area was the result of multiple factors. Among them, topographic relief and slope were the key factors. The synergistic enhancement among these driving factors intensified the spatial differentiation of habitat quality. The findings of this study can provide a scientific basis for land resources utilization and ecosystem restoration in the arid and semi-arid land.

submitted time 2022-06-17 Cooperative journals:《Journal of Arid Land》 Hits288Downloads159 Comment 0

4. chinaXiv:202206.00154 [pdf]

Transformation among precipitation, surface water, groundwater, and mine water in the Hailiutu River Basin under mining activity

LI Qian; MA Long; LIU Tingxi
Subjects: Geosciences >> Hydrology

Abstract: Coal mining has changed the hydrogeological conditions of river basins, and studying how the relationship among different types of water body has changed under the influence of coal mining is of great significance for understanding the regional hydrological cycle. We analyzed the temporal and spatial distribution of hydrochemical properties and environmental isotopes in the Hailiutu River Basin (HRB), China with a mixed model. The results showed that: (1) human activity (e.g., coal mining and agricultural production) causes considerable changes in the hydrochemical properties of surface water in and around the mining areas, and leads to significant increases in the concentrations of Na+ and SO2– 4; (2) precipitation is the main source of water vapour in the HRB. The transformation between surface water and groundwater in the natural watershed is mainly affected by precipitation; and (3) in the mining areas, the average contribution rates of precipitation to the recharge of surface water and groundwater increased by 2.6%–7.9% and 2.7%–9.9%, respectively. Groundwater in the Salawusu Formation constitutes up to 61.3%–72.4% of mine water. Overall, this study is beneficial for quantifying the effects of coal mining on local hydrological cycles. The research results can provide a reference for local water resources management and ecological environment improvement.

submitted time 2022-06-17 Cooperative journals:《Journal of Arid Land》 Hits315Downloads170 Comment 0

5. chinaXiv:202206.00157 [pdf]

Sheltering effect of punched steel plate sand fences for controlling blown sand hazards along the Golmud–Korla Railway: Field observation and numerical simulation studies

ZHANG Kai; TIAN Jianjin; QU Jianjun; ZHAO Liming; LI Sheng
Subjects: Environmental Sciences, Resource Sciences >> Basic Disciplines of Environmental Science and Technology

Abstract: Sand fences made of punched steel plate (PSP) have recently been applied to control wind-blown sand in desertified and Gobi areas due to their strong wind resistance and convenient in situ construction. However, few studies have assessed the protective effect of PSP sand fences, especially through field observations. This study analyzes the effects of double-row PSP sand fences on wind and sand resistance using field observations and a computational fluid dynamics (CFD) numerical simulation. The results of field observations showed that the average windproof efficiencies of the first-row and second-row sand fences were 79.8% and 70.8%, respectively. Moreover, the average windproof efficiencies of the numerical simulation behind the first-row and second-row sand fences were 89.8% and 81.1%, respectively. The sand-resistance efficiency of the double-row PSP sand fences was 65.4%. Sand deposition occurred close to the first-row sand fence; however, there was relatively little sand on the leeward side of the second-row sand fence. The length of sand accumulation near PSP sand fences obtained by numerical simulation was basically consistent with that through field observations, indicating that field observations combined with numerical simulation can provide insight into the complex wind-blown sand field over PSP sand fences. This study indicates that the protection efficiency of the double-row PSP sand fences is sufficient for effective control of sand hazards associated with extremely strong wind in the Gobi areas. The output of this work is expected to improve the future application of PSP sand fences.

submitted time 2022-06-17 Cooperative journals:《Journal of Arid Land》 Hits217Downloads122 Comment 0

6. chinaXiv:202206.00156 [pdf]

Separating emitted dust from the total suspension in airflow based on the characteristics of PM10 vertical concentration profiles on a Gobi surface in northwestern China

ZHANG Chunlai; WANG Xuesong; CEN Songbo; ZHENG Zhongquan Charlie; WANG Zhenting
Subjects: Environmental Sciences, Resource Sciences >> Basic Disciplines of Environmental Science and Technology

Abstract: During aeolian processes, the two most critical factors related to dust emissions are soil particle and aggregate saltation, which greatly affect the vertical profiles of near-surface dust concentrations. In this study, we measured PM10 concentrations at four different heights (0.10, 0.50, 1.00 and 2.00 m) with and without continuous and simultaneous aeolian saltation processes on a Gobi surface in northwestern China from 31 March to 10 April, 2017. We found that the vertical concentration profiles of suspended PM10 matched the log-law model well when there was no aeolian saltation. For the erosion process with saltation, we divided the vertical concentration profiles of PM10 into the saltation-affected layer and the airflow-transport layer according to two different dust sources (i.e., locally emitted PM10 and upwind transported PM10). The transition height between the saltation-affected layer and the airflow-transport layer was not fixed and varied with saltation intensity. From this new perspective, we calculated the airflow-transport layer and the dust emission rate at different times during a wind erosion event occurred on 5 April 2017. We found that dust emissions during wind erosion are primarily controlled by saltation intensity, contributing little to PM10 concentrations above the ground surface compared to PM10 concentrations transported from upwind directions. As erosion progresses, the surface supply of erodible grains is the most crucial factor for saltation intensity. When there was a sufficient amount of erodible grains, there was a significant correlation among the friction velocity, saltation intensity and dust emission rate. However, when supply is limited by factors such as surface renewal or an increase in soil moisture, the friction velocity will not necessarily correlate with the other two factors. Therefore, for the Gobi surface, compared to limiting dust emissions from upwind directions, restricting the transport of suspended dust in its path is by far a more efficient and realistic option for small areas that are often exposed to dust storms. This study provides some theoretical basis for correctly estimating PM10 concentrations in the Gobi areas.

submitted time 2022-06-17 Cooperative journals:《Journal of Arid Land》 Hits225Downloads128 Comment 0

7. chinaXiv:202206.00160 [pdf]

状态焦虑对回溯式时距判断的影响:认知评价和记忆偏向有调节的中介作用

刘静远; 李虹
Subjects: Psychology >> Experimental Psychology

探讨状态焦虑对回溯式时距判断的影响,并检测记忆偏向与认知评价在其中的中介和调节作用。实验1招募大学生60人,随机分为高、低状态焦虑组,采用情绪诱导程序诱导高、低状态焦虑;采用口头估计任务测量回溯式时距判断,考察高、低状态焦虑诱导后的回溯式时距判断差异。实验2在实验1的基础上,招募大学生60人,增加自由回忆任务测量记忆偏向,考察状态焦虑对回溯式时距判断的影响中记忆偏向的中介作用。实验3在实验1和实验2的基础上,招募大学生90人,增加视觉模拟心境量表测量认知评价,考察状态焦虑对回溯式时距判断的影响,并检测认知评价与记忆偏向在其中的作用。结果发现:(1)在回溯式时距判断中,高状态焦虑比低状态焦虑更高估时距;(2)在状态焦虑对回溯式时距判断的影响中,记忆偏向具有中介作用;(3)在状态焦虑对回溯式时距判断的影响中,认知评价和记忆偏向存在有调节的中介作用:只有当认知评价得分较低时,即对于认为焦虑对身体健康有害程度较低的个体而言,在状态焦虑影响回溯式时距判断中,记忆偏向具有完全中介作用,即状态焦虑只通过记忆偏向影响回溯式时距判断。研究结果揭示了焦虑个体回溯式时距判断的内部过程,验证了注意闸门模型中有关用于计时的记忆资源越多对于时距越高估的假设,丰富了焦虑通过记忆偏向影响回溯式时距判断的解释视角,为通过调整认知评价改善焦虑个体时距偏差提供了重要参考。

submitted time 2022-06-17 Hits232Downloads116 Comment 0

8. chinaXiv:202206.00150 [pdf]

在线心理学研究的历史、现状和展望

陈国球; 高晓雪; 鄢忻媛; 杜梦; 臧寅垠; 汪寅
Subjects: Psychology >> Other Disciplines of Psychology

随着近年来互联网的高速发展和新冠疫情的爆发,在线心理学在全球范围内蓬勃发展。在线心理学研究具有样本丰富、高效节约、便于共享、不受时空限制等优势,既有助于缓解线下小样本研究的可重复性危机和低生态效度等问题,还能促进开放科学、公民科学和大团队科学等新型科学发展理念的实践。我国在线心理学领域起步较晚,相关科研资源较少。建立和发展我国独立自主的线上科研平台对人才培养、资源整合、数据安全和科研创新有重要意义。

submitted time 2022-06-17 Hits812Downloads335 Comment 0

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