检索结果-南通市图书馆

Formation mechanisms and remediation techniques for low-efficiency artificial shelter forests on the chinese loess plateau

在线全文

学校读者我要写书评

暂无评论

Journal of Arid Land 2022年第8期14卷 837-848页

作者： WANG Yaobin SHANGGUAN Zhouping State Key Laboratory of Soil Erosion and Dryland Farming on the loess plateau Northwest A&F UniversityYangling 712100China

The construction of artificial shelter forests(ASFs)has resulted in substantial ecological,economic,and societal benefits to the chinese loess plateau(CLP).However,the health and benefits of ASFs are being increasingly threatened by the formation of low-efficiency artificial shelter forests(LEASFs).In this study,LEASFs are systematically analyzed in terms of their status,formation mechanisms,and developmental obstacles.The key restoration techniques and schemes were summarized to improve the quality and efficiency of LEASFs.LEASFs are formed by relatively complex mechanisms,but they arise mainly due to poor habitat conditions,improper tree species selections,mismatch between stands and habitat,extensive forest management measures,and human interferences.The restoration and improvement of LEASFs are hindered by water deficits,mismatch between stands and habitat,single management purpose,and low efficiency.LEASFs are becoming more complex due to their wide range,the challenges associated with their restoration,and insufficient technological measures for their restoration.The key techniques of the quality and efficiency improvement of LEASFs include basic forest tending methods,near-natural restoration,multifunction-oriented improvement,and systematic restoration.An understanding on the formation mechanisms of LEASFs and a scientific approach toward their restoration are urgently needed and critical for the ecological protection and high-quality development of LEASFs on the CLP.Based on these analyses,we recommend strengthening the monitoring and supervision of LEASFs,considering the bearing capacity of regional water resources,implementing multiple restoration techniques,promoting multifunction-oriented ecological development,and exploring new management concepts to achieve the sustainable development of ASFs on the CLP.

关键词： low-efficiency artificial shelter forests restoration forest management multifunctional forestry near-natural forestry Three-North Shelter Forest chinese loess plateau

Identifying eco-functional zones on the chinese loess plateau using ecosystem service bundles

在线全文

学校读者我要写书评

暂无评论

Regional Sustainability 2023年第4期4卷 425-440页

作者： WU Fan LIANG Youjia LIU Lijun YIN Zhangcai HUANG Jiejun School of Resources and Environmental Engineering Wuhan University of TechnologyWuhan430070China College of Resources and Environment Yangtze UniversityWuhan430100China

Optimizing the function of ecosystem services(ESs)is vital for implementing regional ecological management strategies.In this study,we used multi-source data and integrated modelling methods to assess the spatiotemporal variations in eight typical ESs on the chinese loess plateau from 2000 to 2015,including grain production,raw material provision,water conservation,carbon storage service,soil conservation,oxygen production,recreation,and net primary productivity(NPP)services.Then,we divided the ecosystem service bundles(ESBs)according to relationships among the eight ESs,obtaining four types of eco-functional areas at the county(city or banner or district)level based on the spatial clustering of similarities in different ES types.We also identified and assessed the contributions of influencing factors to these eco-functional areas using principal component analysis(PCA)across spatiotemporal scales.We found that the spatiotemporal variations in different ESs were noticeable,with an overall increase in grain production and soil conservation services,no significant change in carbon storage service,and overall decreases in raw material provision,water conservation,oxygen production,recreation,and NPP services.From 2000 to 2015,the number of significant synergistic ES pairs decreased,while that of significant trade-off pairs increased.To the changes of ESBs in the eco-functional areas,the results indicated that the indirect loss of these ESs from forest and grassland due to urban expansion should be reduced in ecological development area(ESB 2)and multi ecological functional area(ESB 3).Meanwhile,crop planting structures and planting densities should be adjusted to reduce ES trade-offs associated with water conservation service in grain-producing area(ESB 4).Lastly,ESB-based ecofunctional zoning can be used to improve ecological restoration management strategies and optimize ecological compensation schemes in ecologically fragile area(ESB 1).

关键词： Ecosystem services Trade-offs Synergy Land use/land cover Climate change Principal component analysis(PCA) chinese loess plateau

Chronology of the Holocene loess-paleosol section and its deposition and pedogenesis on the south of chinese loess plateau

在线全文

学校读者我要写书评

暂无评论

Journal of Geographical Sciences 2008年第4期18卷 425-442页

作者： JIA Yaofeng HUANG Chunchang PANG Jiangli NIU Junjie College of Tourism and Environment Shaanxi Normal University Xl＇an 710062 China North University for Nationalities School of Management Ylnchuan 750021 China

Optically stimulated luminescence （OSL） dating for polymlneral fine-grained loess samples, collected in Laoguantai （LGT） section on the south of the chinese loess plateau, was made by application of single-aliquot regenerative-dose （SAR） protocol. A ＇Double-SAW procedure in which aliquots are subjected to both infrared （IR） and blue stimulations was used and two sets of equivalent dose （De） determinations were produced and assumed to relate predominantly to feldspathic and quartz fine grain populations respectively, The OSL ages estimated from IRSL signals are smaller than those estimated from [post-IR] OSL signals due to the anomalous fading of feldspar IR signals, based on fading experiment, The young ages of the samples near ground surface may be originated from the post-depositional disturbance by the intensifying humanity＇s cultivation since 3.0 ka BP in the Guanzhong Basin, south of the chinese loess plateau. Based on OSL dating, as well as field observations and stratigraphic correlation, we determine the chronology of the LGT Ioess-paleosol sequence. In combination with climate proxy records, it is indicated that aeolian loess deposition and pedogenesis underwent polyphase changes during the Holocene, likely to have been driven by shifts in the East Asian monsoon. This suggests that aeolian loess deposition is episodic and highly variable, with contributions from non-aeolian processes such as alluvial deposition found in the area.

关键词： chinese loess plateau loess deposition and pedogenesis East Asian monsoon Hoiocene

Spatial-temporal pattern and formation mechanism of county urbanization on the chinese loess plateau

在线全文

学校读者我要写书评

暂无评论

Journal of Mountain Science 2021年第4期18卷 1093-1111页

作者： SONG Yong-yong MA Bei-bei DAI Lan-hai XUE Dong-Qian XIA Si-you WANG Peng-tao School of Geography and Tourism Shaanxi Normal UniversityXi'an 710119China College of History Culture and TourismHexi UniversityZhangye 734000China Institute of Geographic Sciences and Natural Resources Research Chinese Academy of SciencesBeijing 100101China School of Tourism&Research Institute of Human Geography Xi'an International Studies UniversityXi'an 710128China

Urbanization is a comprehensive and complex socioeconomic phenomenon that plays an influential role in promoting global socioeconomic development.The loess plateau region is an important part of the China’s ecological security pattern,and occupies an important position in the implementation of China’s new-type urbanization strategy and the realization of the urban dream.The characteristics of the staged changes and regional differentiation of urbanization in the area from 1990 to 2018 were studied with focus on regions and subregions by selecting 341 county-level administrative units on the chinese loess plateau as the research area,and employing partition analysis and geographic detector methods.This revealed the formation mechanism of the spatial differentiation pattern of urbanization on the loess plateau.We found that the urbanization of the loess plateau,previously in a slow growth phase,entered the accelerated development phase,presenting a macro pattern of high rates of urbanization in central and eastern areas and low rates in western areas.The formation of the regional differentiation patterns of urbanization on the loess plateau were the combined results of natural geographical and socioeconomic factors.Among these factors,the interaction of any two factors had a stronger impact on regional urbanization patterns than a single factor,which was specifically manifested as nonlinear or bi-factor enhancement effects.The findings of this paper may provide a theoretical reference and scientific basis for the scientific promotion of healthy urbanization on the chinese loess plateau and the ecologically fragile areas of developing countries around the world.

关键词： Urbanization Spatial-temporal pattern Influencing factors Driving mechanism Geographical detector chinese loess plateau

Late Cenozoic uplift of the Liupan Mountains:Evidence from the Neogene loess deposits

在线全文

学校读者我要写书评

暂无评论

Science China Earth Sciences 2024年第5期67卷 1480-1488页

作者： Zhilin HE Yansong QIAO Zhengtang GUO Chaoqin CHEN Long CHEN Yang FU Ye YANG Yanxia LIANG Xinru LIN Guoqiao XIAO Tao ZHAN Key Laboratory of Cenozoic Geology and Environment Institute of Geology and GeophysicsChinese Academy of SciencesBeijing 100029China Institute of Geomechanics Chinese Academy of Geological SciencesBeijing 100081China CAS Center for Excellence in Life and Paleoenvironment Beijing 100044China University of chinese Academy of Sciences Beijing 100049China Institute of Ecological Geology Survey and Research of Heilongjiang Province Harbin 150030China School of Geography and Information Engineering China University of GeosciencesWuhan 430078China School of Earth Sciences China University of GeosciencesWuhan 430074China Natural Resources Survey Institute of Heilongjiang Province Harbin 150036China

The Liupan Mountains,one of the important mountain ranges in western China,are located on the boundary between the northeastern Tibetan plateau and the Ordos Block.The uplift history of the Liupan Mountains remains controversial.loess deposits are good tracers of regional tectonic and geomorphic changes,because loess is sensitive to erosion and the formation and preservation of loess requires relatively flat highlands and relatively stable tectonic environments.We investigated the distribution of Neogene loess deposits on the western piedmont of the Liupan Mountains and examined a near-continuous loess section(Nanping section)on the piedmont alluvial highlands.Correlation of magnetic susceptibility stratigraphy with the QA-ⅠMiocene loess sequence dates this 56-m section covering the interval from~8.1 to 6.2 Ma.The lower boundary age of this section,together with previously reported Zhuanglang red clay(sand-gravel layers with intercalated loess during~9–8 Ma and near-continuous loess during~8–4.8 Ma)and Chaona red clay(~8.1–2.58 Ma),indicates that the Liupan Mountains were uplifted in the late Miocene(~9–8 Ma)and basically formed by~8 Ma,attesting to no intense mountain building since that time.In addition,based on the information from the Zhuanglang core and the QA-Ⅰsection,we infer that sizable parts of the Liupan Mountains were uplifted during the late Oligocene–early Miocene and did not experience intense uplift during~22–9 Ma.

关键词： Liupan Mountains Mountain building Neogene loess chinese loess plateau Late Miocene Late Oligocene–early Miocene

Vegetation and environmental changes in western chinese loess plateau since 13.0 ka BP

在线全文

学校读者我要写书评

暂无评论

Journal of Geographical Sciences 2010年第2期20卷 177-192页

作者： SUN Aizhi FENG Zhaodong MA Yuzhen School of Geography Science Southwest University Chongqing 400715 China MOE Key Laboratory of Western China＇s Environmental Systems College of Earth ＆ Environment SciencesLanzhou University Lanzhou 730000 China Department of Geology Baylor University Waco TX76795 USA College of Resources Science and Technology Research Beijing Normal University Beijing 100875 China

Pollen records from the chinese loess plateau revealed a detailed history of vegetation variation and associated climate changes during the last 13.0 ka BP. Before 12.1 ka BP, steppe or desert-steppe vegetation dominated landscape then was replaced by a coniferous forest under a generally wet climate （12.1-11.0 ka BP）. The vegetation was deteriorated into steppe landscape and further into a desert-steppe landscape between 11.0 and 9.8 ka BP. After a brief episode of a cool and wet climate （9.8-9.6 ka BP）, a relatively mild and dry condition prevailed during the early Holocene （9.6-7.6 ka BP）. The most favourable climate of warm and humid period occurred during mid-Holocene （7.6-4.0 ka BP） marked by forest-steppe landscape and vegetation alternatively changed between steppe and desert-steppe from -4.0 to -1.0 ka BP.

关键词： chinese loess plateau arid and semi-arid region pollen assemblage climate change

Dynamics of NDVI and its influencing factors in the chinese loess plateau during 2002-2018

在线全文

学校读者我要写书评

暂无评论

Regional Sustainability 2021年第1期2卷 36-46页

作者： Peng He Lishuai Xu Zhengchun Liu Yaodong Jing Wenbo Zhu College of Resources and Environment Shanxi Agricultural UniversityTaigu030801China

Understanding the spatio-temporal changes of vegetation and its climatic control factors can provide an important theoretical basis for the protection and restoration of eco-environments.In this study,we analyzed the normalized difference vegetation index(NDVI)in the chinese loess plateau(CLP)from 2002 to 2018 via trend analysis,stability analysis,and Mann-Kendall mutation test to investigate the change of vegetation.In addition,we also used the skewness analysis and correlation analysis to explore the contribution of climate change and human activities on regional vegetation changes.The results indicated that the overall increasing trend of NDVI from 2002 to 2018 was significant The areas showing increased NDVI were mainly distributed in the south-eastern CLP and the irrigation districts of the Yellow River to the north and west of the CLP,while the areas showing decreased NDVl were concentrated in the desert of the westem Ordos plateau,Longzhong loess plateau,and the built-up and adjacent areas.Precipitation was the dominant factor contributing to vegetation growth in the CLP,while vegetation was less dependent onprecipitation in the irigation districts.The increasement of NDVI has led to a prolonged responsetime of vegetation to water stress and a lag effect of less than two months in the CLP.The effect of temperature on NDVI was not significant;significant negative correlations between NDVI and temperature were found only in the desert,the Guanzhong Plain,the southem Liupan Mountains,and the southeastem Taihang Mountains,owing to high temperatures,urban heat islands,and large cloud cover in mountainous areas.Affected by the"Grain for Green Program"(GGP),NDVIin the CLP increased from 2002 to 2018;however,the increasing trends of NDNI for differentvegetation cover types were significantly different owing to the difference in background status.The increasing contribution rate of NDVI in the CLP mainly came from crops and steppes.Urban not only led to the destruction of vegetation but also had radiation effect ca

关键词： chinese loess plateau NDVI Vegetation cover types Temperature Precipitation Human activities

Plant type effect overweighs seasonal variation in n-alkanoic acid biomarker on regional loess plateau of China

在线全文

学校读者我要写书评

暂无评论

Science China Earth Sciences 2024年第8期67卷 2547-2562页

作者： Jinzhao LIU S.Nemiah LADD Jiaju ZHAO Dongna YAN Ding HE Yunning CAO Zhisheng AN State Key Laboratory of loess and Quaternary Geology Institute of Earth Environment Chinese Academy of Sciences CAS Center for Excellence in Quaternary Science and Global Change Department of Environmental Sciences University of Basel Department of Ocean Science and Center for Ocean Research in Hong Kong and Macao The Hong Kong University of Science and Technology

The effect of plant type on n-alkane biomarker has been widely studied, but the influence of plant type on n-alkanoic acids（n-FAs） has received less attention. Understanding the effect of the distribution of n-FAs and their hydrogen isotope composition(δ2HFA) is critical for interpreting sedimentary δ2HFAvalues as proxies of hydroclimate and/or vegetation changes.In this study, we systematically investigated the distribution ofn-FAs and δ2HFAvalues across seasons on the chinese loess plateau（CLP）. Our results showed that there were no significant seasonal differences in n-FAs distribution and δ2HFAvalues, but there were significant differences in δ2HFAvalues across plant types. The δ2HFAvalues ranged from-185‰ to-125‰ in dicots（-161‰±28‰）, and from-215‰ to-170‰ in monocots（-196‰±22‰） on the CLP. Isotope fractionation between δ2HFAvalues and precipitation δ2H(εFA-P) was also2H-enriched in dicots relative to monocots. At the regional scale of the CLP, δ2HFAvalues were not correlated with δ2H values of precipitation. However, δ2HFAvalues from the CLP were similar to expectations from a global comparison, both in terms of their mean values and high variability among plants growing in sites with similar δ2H values of precipitation. As some of this variability in εFA-Pis due to the effect of plant type, a careful assessment of the likely sources of waxes in terrestrial sediments is critical when using δ2HFAvalues for paleohydroclimate reconstruction.

关键词： n -Alkanoic acid Hydrogen isotope Plant type Paleohydroclimate chinese loess plateau

Wind-blown origin of Dongwan late Miocene-Pliocene dust sequence documented by land snail record in western chinese loess plateau

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Wind-blown origin of Dongwan late Miocene-Pliocene dust sequ...