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1.
This paper aims to the debate on the nexus between informal economies and the environment by investigating the long-term dynamic impacts of China's informal economies on pollution and considering regional differences in informal economies' pollution.This paper uses the Multiple Indicators Multiple Causes(MIMIC) model to estimate the size of informal economies and employs econometric models to examine their relationships to pollution based on provincial-level panel data from 2000 to 2017. The results indicate that informal economies' effects on environmental pollution are not purely positive or negative. Rather, our model indicates that there is an inverted U-shaped relationship between informal economies and pollution in the long run in China; this means that the level of environmental pollution increases at first and then decreases with the growth of informal economies. Further analysis shows that while this inverted, U-shaped relationship is significant in different regions of China, it is affected by different environmental impact factors. The paper concludes by discussing the policy implications for environmental protection and sustainable development.  相似文献   

2.
Ecosystem services(ES) are highly impacted by human-induced land-use change.Progressive urbanization and agricultural land abandonment in Western Europe necessitate assessments of future land-change impacts on ES to ensure sustainable service management. The present study aims at evaluating future demand and supply of three key services(flood protection, nearby recreation and biodiversity) in the mountainous region of Vorarlberg, Austria. We mapped the ES for the referenced time step 2016 and two scenarios for 2050,assuming the continuation of current land-change trends and pressure on landscape development.Results for the referenced landscape in 2016 show the highest ES supply for intermediate levels, while ES supply was low in the lowlands and valley bottoms and in high-elevation areas. We found a high positive correlation of ES with the distribution of forested areas. In contrast, service demand was highest in lowelevation areas and decreased with increasing elevation. This indicates that densely settled and intensively used agricultural areas currently suffer from ES undersupply. The projected future development of land use showed an increase in both supply and demand of the selected ES. The overall service supply increased more than the respective demand due to some reforestation of open land. As forests were found to be important synergistic areas for overall service provision, we expect decreasing demand on related services. Locally, demand was found to exceed the supply of ES, especially in the densely populated Rhine valley-requiring further policy interventions. Such ES-related information may contribute to regional policy making and ensure the long-term provision of ESs for future generations.  相似文献   

3.
Palm oil is of great potential as one of the sustainable alternatives to fish oil (FO) in aquafeeds. In this present study, five isonitrogenous diets (32% crude protein) with elevated palm oil levels of 0%, 2%, 4%, 6% and 8% were used during an 8-week feeding trial to evaluate its effects on RNA/DNA ratio and lipoprotein lipase (LPL) and MyoD mRNA expressions in muscle of Oreochromis niloticus. The results showed that RNA, DNA content as well as ratio of RNA to DNA were significantly affected (P < 0.05), in each case the highest was recorded in fish group subjected to 6% palm oil level. There was a strong positive correlation between nucleic acid concentration (RNA concentration and RNA: DNA ratio) and specific growth rate (SGR), protein efficiency ratio (PER), while a negative correlation existed between nucleic acid concentration (RNA concentration and RNA: DNA ratio) and feed conversion ratio (FCR). The mRNA expressions of LPL and MyoD in muscle were not significantly affected by the different palm oil levels, although the highest expression was observed in fish fed with 6% palm oil level. There also existed a strong positive correlation between the mRNA expression of LPL, MyoD and SGR, PER, while their correlation with FCR was negative. In conclusion, elevated palm oil affected the RNA, DNA concentration as well as RNA/DNA ratio significantly, although the mRNA expression of LPL and MyoD were not affected significantly by elevated palm oil levels.  相似文献   

4.
China′s economy and transport infrastructure have both experienced rapid development since 1978, and especially since 1990. Today, China is the second-largest economic entity in terms of GDP and has the largest high-speed rail(HSR) network and the second-largest expressway network in the world. This paper explores the relationship between accessibility and economic growth in China from 1990 to 2010. In the study, the basic research units include 333 prefecture-level cities and four municipalities. We explore a bivariate analysis framework of accessibility and economic growth, and their increase rates, to examine this relationship using long-term panel data. The results indicate that, first, accessibility and economic growth show a significant positive relationship using both cross-section and panel data, while the increase rate in accessibility and GDP indicate no significant relationship using cross-section data and a poor significant relationship using panel data. Second, the distributions of local advantage are uneven. Cities with low local advantage with respect to accessibility and GDP are mainly located in China′s eastern coastal region or the provincial capitals, while those with low local advantage in terms of their increase rates are located in the western region. Third, as China′s economic growth and transport networks have evolved, the distribution of local advantage shows little change in terms of accessibility and GDP, but a greater change in terms of their increase rates, which is largely influenced by the distribution of expressway and HSR networks.  相似文献   

5.
结合遥感、地理信息系统、景观生态学和空间分析等理论,分析了新疆地区2000~2015年农业景观格局的时空动态变化特征,测算了农业生态系统服务价值,通过相关分析进一步研究了农业景观格局与生态系统服务价值的关联,为促进区域土地资源合理利用和生态农业发展提供科学依据。结果表明,新疆农业生态系统正朝着多样化、稳定化的方向发展;农业生态系统服务价值显著增长,但区域间的价值差异较大,呈现北疆高南疆低的分布格局;景观面积、斑块数和景观形状对新疆地区农业生态系统服务价值影响较大且均呈现明显正相关关系。  相似文献   

6.
This study has examined the temporal variation in monthly, seasonal annual precipitation over the Western Himalayan Region(WHR) and the influence of global teleconnections, like the North Atlantic Oscillation(NAO) and Southern Oscillation(SO) Indices on seasonal annual precipitation. The Mann–Kendall non-parametric test is applied for trend detection and the Pettitt–Mann–Whitney test is used to detect possible shift. Maximum entropy spectral analysis is applied to find the periodicity in annual seasonal precipitation. The study shows a non-significant decreasing trend in annual precipitation over WHR for the period 1857-2006. However, in seasonal precipitation, a significant decreasing trend is observed in monsoon and a significant increasing trend in post-monsoon season during the same period. The significant decrease in monsoon precipitation may be due to weakening of its teleconnection with NAO as well as SO Indices mainly during last three decades. It is observed that the probable change of year in annual monsoon precipitation over WHR is 1979. The study also shows significant periodicities of 2.3-2.9 years and of 3.9-4.7 years in annual seasonal precipitation over WHR.  相似文献   

7.
Study results in this paper have indicated that the Holocene climate in Xinjiang, Northwestem China has been alternating between wet and dry conditions, and was punctuated with a series of abrupt climate shifts. A sediment core taken from Barkol Lake in the northern Xinjiang of Northwest China was analyzed at 1 cm interval for grain-size distribution. Abrupt climate shifts revealed by the grain-size proxy occurred at ca 1.4, 3.0, 4.3, 5.6, 8.0 cal kyr B.E, which were well correlated to both the abrupt shifts recorded in the North Atlantic Ocean （NAO） and the Holocene sea surface temperature （SST） cooling events in the Arabian Ocean. The correlation indicated that the climatic changes in the extreme arid Northwest China were associated with the NAO, probably via the North Atlantic Oscillation-affected westerly winds. The strength and position of westerly winds probably modulated the Siberian-Mongolian high- pressure system （winter monsoon）, and played an important role in climate change of Northwest China. Moreover, an evident drought interval during the middle Holocene was also revealed by grain-size proxy.  相似文献   

8.
The relationship between livelihood diversification of farm households and cultivated land utilization has become a core research topic related to global environmental change. Agro-pastoral ecologically-vulnerable areas face challenges such as insufficient ecosystem conservation, low agricultural production, and weak economies. In this study, 215 farm households from Zhengxiangbai Banner, Taibus Banner, and Duolun County of Inner Mongolia were surveyed. The sustainable livelihoods framework of the United Kingdom(UK) Department for International Development(DFID) was used to measure the livelihood capital of these farm households. A one-way analysis of variance(ANOVA) was applied to examine the differences in the livelihood capital of different types households, and a correlation analysis was applied to analyze its impact on cultivated land utilization. Results showed that households with non-farming activities accounted for 64.7% of the total surveyed households, and non-farming employment was becoming more prevalent. Physical and financial capital was the driving factors for livelihood diversity. Each livelihood capital had key factors that affected household farmland use behaviors, such as the age of householder, the labor ratio, proportion of income, farmland scale, number of machines, and these had a significantly positive or negative influence on farmland use. Full-time farming households were more likely to transfer the land into cultivation and invest more labor, while non-farming households with high income were likely to transfer farmland out and invest more money to develop efficient farming or improve the employment skills. The results of this study suggest that policymakers need to fully consider livelihood changes of local households. It is effective to strengthen labor training, create farmland market and improve the efficiency of farmland utilization. We hope to achieve a win-win scenario to improve local economies and ecosystem conservation.  相似文献   

9.
This study investigates the Arctic Ocean warming episodes in the 20th century using both a high-resolution coupled global climate model and historical observations. The model, with no flux adjustment, reproduces well the Atlantic Water core temperature （AWCT） in the Arctic Ocean and shows that four largest decadalscale warming episodes occurred in the 1930s, 70s, 80s, and 90s, in agreement with the hydrographic observational data. The difference is that there was no pre-warming prior to the 1930s episode, while there were two pre-warming episodes in the 1970s and 80s prior to the 1990s, leading the 1990s into the largest and prolonged warming in the 20th century. Over the last century, the simulated heat transport via Fram Strait and the Barents Sea was estimated to be, on average, 31.32 TW and 14.82 TW, respectively, while the Bering Strait also provides 15.94 TW heat into the west- ern Arctic Ocean. Heat transport into the Arctic Ocean by the Atlantic Water via Fram Strait and the Barents Sea correlates significantly with AWCT （ C = 0.75 ） at 0- lag. The modeled North Atlantic Oscillation （NAO） index has a significant correlation with the heat transport （ C = 0.37 ）. The observed AWCT has a significant correlation with both the modeled AWCT （ C =0.49） and the heat transport （ C =0.41 ）. However, the modeled NAO index does not significantly correlate with either the observed AWCT （ C = 0.03 ） or modeled AWCT （ C = 0.16 ） at a zero-lag, indicating that the Arctic climate system is far more complex than expected.  相似文献   

10.
Frozen ground degradation under a warming climate profoundly influences the growth of alpine vegetation in the source region of the Qinghai-Tibet Plateau. This study investigated spatiotemporal variations in the frozen ground distribution, the active layer thickness(ALT) of permafrost(PF) soil and the soil freeze depth(SFD) in seasonally frozen soil from 1980 to 2018 using the temperature at the top of permafrost(TTOP) model and Stefan equation. We compared the effects of these variations on vegetation growth among different frozen ground types and vegetation types in the source region of the Yellow River(SRYR). The results showed that approximately half of the PF area(20.37% of the SRYR) was projected to degrade into seasonally frozen ground(SFG) during the past four decades; furthermore, the areal average ALT increased by 3.47 cm/yr, and the areal average SFD decreased by 0.93 cm/yr from 1980 to 2018. Accordingly, the growing season Normalized Difference Vegetation Index(NDVI) presented an increasing trend of 0.002/10 yr, and the increase rate and proportion of areas with NDVI increase were largest in the transition zone where PF degraded to SFG(the PF to SFG zone). A correlation analysis indicated that variations in ALT and SFD in the SRYR were significantly correlated with increases of NDVI in the growing season. However, a rapid decrease in SFD(-1.4 cm/10 yr) could have reduced the soil moisture and, thus, decreased the NDVI. The NDVI for most vegetation types exhibited a significant positive correlation with ALT and a negative correlation with SFD. However, the steppe NDVI exhibited a significant negative correlation with the SFD in the PF to SFG zone but a positive correlation in the SFG zone, which was mainly limited by water condition because of different change rates of the SFD.  相似文献   

11.
三江源地区是国家重要生态安全屏障和生态文明先行示范区。科学认知三江源地区生态空间、农业空间、城镇空间的空间格局演变特征及驱动机制,对于促进国土空间格局优化具有重要意义。首先从单一土地利用类型入手,分析1992―2020年的变化特征;然后结合土地分类和量化评价辨识出农牧空间,进而界定出“三区空间”并对其演变特征进行分析;最后,利用地理探测器分析变化背后的驱动机制。结果表明：① 三江源地区城镇空间增幅达774.56%;生态空间和农业空间以2005年和2015年为转折点,分别呈“U”字型和倒“U”字型变化趋势;② 研究区仅发生了4种交叉转换：生态空间转农业空间规模为1154.1 km²,多发生在气候变化主导区,转化量大但速度在逐步放缓;农业空间转生态空间规模为1140.8 km²,多分布在气候与人类活动共同作用区,转化速度呈明显变快趋势;农业空间和生态空间转为城镇空间的总量分别为41.0 km²和12.3 km²,多分布在县（市）驻地镇附近,转化速度在三个阶段表现为“缓慢增长―变快―减缓”的态势;③ 地理基础条件是“三区空间”格局演化的基本动力和前提,制约着交叉转换的位置和方向;社会经济因素是演化的关键驱动力,对交叉转换规模和速度均具有显著影响;生态保护政策在2005年之后驱动作用显著,尤其在“生态―农业”空间的相互置换过程中发挥着稳定作用。本研究可为牧业地区主体功能降尺度传导和国土空间用途管制提供新思路,可应用于三江源地区生态环境保护决策和各级国土空间规划编制工作。  相似文献   

12.
《山地科学学报》2020,17(1):147-155
Agricultural development in povertystricken areas is a major problem affecting agricultural modernization in China. This study discusses the restrictive factors affecting agricultural development in impoverished areas in China. A typical impoverished mountainous area, Min County,was selected for a case study. A regression analysis on the factors and characteristics of agricultural development in Min County between 1982 and 2017 was performed in this study. Taking agricultural output as the dependent variable, we selected nine main inputs of agricultural production in impoverished mountainous areas as the independent variables. Ridge regression analysis was carried out by testing for unit root and co-integration to verify the equilibrium relationship of the data. The results showed that the real Gross domestic product(GDP)per capita, the non-grain area ratio, the proportion of government expenditure on agriculture support to total expenditure, and the amount of chemical fertilizer applied in unit cultivated land area were the four most significant factors. The proportion of government expenditure on agriculture support to total expenditure was a negative influence, whereas the other three significant factors had a positive influence on agricultural output. This study highlights about the most significant factors affecting the agricultural development of impoverished mountainous regions in China.  相似文献   

13.
In this study, an inventory analysis approach was used to investigate the intensity of agricultural non-point source pollution(ANSP) and its spatial convergence at national and provincial levels in China from 1999 to 2017. On this basis, spatial factors affecting ANSP were explored by constructing a spatial econometric model. The results indicate that: 1) The intensity of China's ANSP emission showed an overall upward trend and an obvious spatial difference, with the values being high in the eastern and central regions and relatively low in the western region. 2) Significant spatial agglomeration was shown in China's ANSP intensity, and the agglomeration effect was increasing gradually. 3) In the convergence analysis, a spatial lag model was found applicable for interpretation of the ANSP intensity, with the convergence rate being accelerated after considering the spatial factors but slower than that of regional economic growth.4) The spatial factors affecting the ANSP intensity are shown to be reduced by improving agricultural infrastructure investment, laborforce quality, and crop production ratio, while the expansion of agricultural economy scale and precipitation and runoff have positive impact on ANSP in the study region. However, agricultural research and development(RD) investment showed no direct significant effect on the ANSP intensity. Meanwhile, improving the quality of the labor force would significantly reduce the ANSP intensity in the surrounding areas, while the precipitation and runoff would significantly increase the pollution of neighboring regions. This research has laid a theoretical basis for formulation and optimization of ANSP prevention strategies in China and related regions.  相似文献   

14.
Long-range precipitation forecasts are useful when managing water supplies.Oceanicatmospheric oscillations have been shown to influence precipitation.Due to a longer cycle of some of the oscillations,a short instrumental record is a limitation in using them for long-range precipitation forecasts.The influence of oscillations over precipitation is observable within paleoclimate reconstructions;however,there have been no attempts to utilize these reconstructions in precipitation forecasting.A data-driven model,KStar,is used for obtaining long-range precipitation forecasts by extending the period of record through the use of reconstructions of oscillations.KStar is a nearest neighbor algorithm with an entropy-based distance function.Oceanic-atmospheric oscillation reconstructions include the El Nino-Southern Oscillation(ENSO),the Pacific Decadal Oscillation(PDO),the North Atlantic Oscillation(NAO),and the Atlantic Multi-decadal Oscillation(AMO).Precipitation is forecasted for 20 climate divisions in the western United States.A 10-year moving average is applied to aid in the identification of oscillation phases.A lead time approach is used to simulate a one-year forecast,with a 10-fold cross-validation technique to test the models.Reconstructions are used from 1658-1899,while the observed record is used from 1900-2007.The model is evaluated using mean absolute error(MAE),root mean squared error(RMSE),RMSE-observations standard deviation ratio(RSR),Pearson’s correlation coefficient(R),NashSutcliffe coefficient of efficiency(NSE),and linear error in probability space(LEPS) skill score(SK).The role of individual and coupled oscillations is evaluated by dropping oscillations in the model.The results indicate ’good’ precipitation estimates using the KStar model.This modeling technique is expected to be useful for long-term water resources planning and management.  相似文献   

15.
通过大量野外观察、分析测试和综合研究,结合覆盖全区不同比例尺的区域地质调查资料,对柴达木盆地及其邻区早—中二叠世构造岩相古地理格局进行了研究,并探讨了其形成机制.结果表明:柴达木盆地及其邻区中、北部早—中二叠世为陆内盆山裂谷系统,主体处于伸展构造背景,总体表现为堑垒相间的构造古地理格局;南部为巴颜喀拉洋盆,早—中二叠世是巴颜喀拉洋盆扩张最为剧烈且规模最大的时期,巴颜喀拉洋盆中洋岛、海山遍布;早—中二叠世晚期强烈的华力西构造运动使古板块间的相对运动加剧,巴颜喀拉洋盆大洋岩石圈板块向北强烈俯冲,形成东昆仑陆缘岩浆弧及其南部增生带,东昆仑陆缘岩浆弧岩浆活动十分强烈,宗务隆山—西秦岭陆源裂谷盆地进一步发育,形成十分复杂的构造岩相古地理格局.早—中二叠世是研究区地球动力学机制从强烈扩张到强烈汇聚的转折时期,加强其构造岩相古地理研究对建立该区地层序列、探讨其地质演化历史以及指导找矿等均具有重要意义.  相似文献   

16.
The East Asian monsoon has a tremendous impact on agricultural production in China. An assessment of the risk of drought disaster in maize-producing regions is therefore important in ensuring a reduction in such disasters and an increase in food security. A risk assessment model, EPIC(Environmental Policy Integrated Climate) model, for maize drought disasters based on the Erosion Productivity Impact Calculator crop model is proposed for areas with the topographic characteristics of the mountainous karst region in southwest China. This region has one of the highest levels of environmental degradation in China. The results showed that the hazard risk level for the maize zone of southwest China is generally high. Most hazard index values were between 0.4 and 0.5,accounting for 47.32% of total study area. However,the risk level for drought loss was low. Most of the loss rate was 0.1, accounting for 96.24% of the total study area. The three high-risk areas were mainlydistributed in the parallel ridge–valley areas in the east of Sichuan Province, the West Mountain area of Guizhou Province, and the south of Yunnan Province.These results provide a scientific basis and support for the reduction of agricultural drought disasters and an increase in food security in the southwest China maize zone.  相似文献   

17.
The northeastern China, the United States, and the western Europe are important agricultural regions both on the global and regional scales. The western Europe has a longer history of agricultural land development than the eastern United States. These two regions have changed from the deforestation and reclamation phase in the past to the current land abandonment and reforestation phase. Compared with the two regions, large-scale land exploitation has only been practiced in the northeastern China during the last century. After a short high-intensity deforestation and reclamation period, agricultural and forest lands are basically in a dynamic steady state. By comparing domestic and international agro-forestry development and considering the ecological environment and socio-economic benefits that can be derived from agro-forestry, this paper suggests that large area of reforestation would be inevitable in future though persistent and large agricultural demand in coming decades even more. And local reforestation at slope farmland with ecological vulnerability should be imperative at present to avoid severer damage. At the same time, from the perspective of Land Change Science, the results demonstrate that the research on land use change in the agro-forestry ecotone is typical and critical, particularly those dealing with the analysis of spatial and temporal characteristics and the simulation of climate, hydrology, and other environmental effects.  相似文献   

18.
Due to high intensity agricultural exploitation since the middle of the 20 th century, farmland gullies have become a pervasive form of water erosion in Northeast China. Yet few researches are concentrated on how topography and land use affect long-term gully development in this region. In this study, gully distribution in a village with an area of 24.2 km~2 in the central Mollisols area of Northeast China in different times were compared by Aerial photography(1968), Quickbird image(2009) and field survey, and factors affecting gully development including land use and topography were analyzed. The results showed that the total gully number decreased from 104 to 69, while occupying area rose from 34.8 ha to 78.4 ha from 1968 to 2009. Fundamental gully distribution had been formed by 1968 as most of 2009′s gullies were evolved from 1968′s gullies′ merge and width expansion process, and new gullies those initiated after 1968 occupied only 7% of total gully area in 2009. Gully area increasing ratio in grassland was the highest and that in forestland was the lowest. The threshold catchment area between simple and complex gully development was around 15 ha to 25 ha. This threshold value sets apart catchment areas that will develop simple or complex gullies in areas with similar environmental conditions. Gully control measurements were urgent because if appropriate gully control implements would not be applied, present gully erosion crisis could be doubled within 50 years.  相似文献   

19.
基于植被状态指数的云南省农业干旱状况时空分析   总被引：2，自引：0，他引：2  
本文首先计算了云南省2004-2013年农业干旱指数VCI,然后使用Pearson相关系数评价降水与VCI的相关性,基于VCI识别云南省2004-2013年农业干旱事件,最后,与SPEI气象干旱识别结果进行对比分析,在VCI农业干旱识别的基础上,使用干旱频率和干旱面积占比指标分析了云南省2004-2013年农业干旱时空特征。结果表明：降水只是影响VCI指数的关键因素之一;VCI和SPEI指数均能够较好对干旱进行监测并识别典型干旱,但两者的识别结果存在差异;云南省农业干旱频率在春冬两季较高,夏季较低,秋季介于夏季和春冬季之间;春夏冬三季农业干旱频率空间分布较为均匀,秋季农业干旱频率呈南低北高的分布态势,整体上北部干旱频率高于南部;2004-2013年云南省整体干旱面积占比呈现先减小后增加再波动的趋势,春冬两季整体干旱面积占比最高,分别为46.63%和47.18%,呈现下降趋势,夏季整体干旱面积占比最低,为43.81%,呈现上升趋势,秋季整体干旱面积占比介于冬春季和夏季之间,为45.74%,呈现下降趋势。总之,云南省农业干旱春冬易发性最高,影响范围最大,夏季易发性最低,影响范围最小。  相似文献   

20.
基于NAO99b全球海潮模型、NAO99Jb区域海潮模型、验潮站资料和SRTM地形数据确定的高空间分辨率海陆边界数据,构建我国沿海和岛屿高精度重力海潮负荷改正模型。以马祖岛为例介绍该模型,并采用实测的绝对重力测量资料进行验证。结果表明,经该模型改正后的重力观测精度明显提高。  相似文献   

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