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Dynamics of Saline-alkali Land and Its Ecological Regionalization in Western Songnen Plain, China 被引量:18
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作者 YANG Jiuchun ZHANG Shuwen +4 位作者 LI Ying BU Kun ZHANG Yubo CHANG Liping ZHANG Yangzhen 《Chinese Geographical Science》 SCIE CSCD 2010年第2期159-166,共8页
As the important reserve land resources for food production,saline-alkali land should play a significant role to ensure the national food security in the context of global food crisis. The western Songnen Plain is one... As the important reserve land resources for food production,saline-alkali land should play a significant role to ensure the national food security in the context of global food crisis. The western Songnen Plain is one of main distribution regions of saline-alkali land in China,with great potential in agricultural development. In this study,the extent,transformation,spatial distribution and temporal change of saline-alkali land in the western Songnen Plain during 1954–2005 were investigated by using remote sensing and GIS spatial analysis methods. Saline-alkali land change was detected from a temporal series of topographic maps in 1954,satellite images of Landsat MSS in 1976,Landsat TM/ETM in 1988,2000 and 2005 through artificial visual interpretation. The results indicated a significant expansion in saline-alkali land area and aggravation in salinization. The area of saline-alkali land had increased from 401.48×103 ha in 1954 to 1 097.45×103 ha in 2005. While the ratio of light,moderate and serious salinized land areas changed from 6.72︰2.92︰1.00 to 1.25︰1.06︰1.00 in the study period. Grassland,cropland,swampland and water body were the major land use and land cover types from which saline-alkali land transformed. And the secondary salinization occured mainly in Da′an City,Tongyu County,Changling County,Daqing City,Dorbod Mongolian Autonomous County and Zhaoyuan County. Finally,seven large ecoregions and 14 corresponding sub-ecoregions were delineated out based on spatio-temopral dynamic characteristics of saline-alkali land and geo-relational environmental attributes. According to the results,measures of amelioration and ways of development of saline-alkali land in the western Songnen Plain were put forward. 展开更多
关键词 saline-alkali land SALINIZATION ecological regionalization food security Songnen Plain
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A GIS-based Tupu Analysis of Dynamics of Saline-alkali Land in Western Jilin Province 被引量:1
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作者 REN Chunying ZHANG Bai +3 位作者 WANG Zongming SONG Kaishan LIU Dianwei LIU Zhiming 《Chinese Geographical Science》 SCIE CSCD 2007年第4期333-340,共8页
Based on Tupu theory, this paper studied the dynamic changes, conversion modes, expansion intensity and landscape attributes of the saline-alkali lands in Changling County, Zhenlai County and Da'an City of the wes... Based on Tupu theory, this paper studied the dynamic changes, conversion modes, expansion intensity and landscape attributes of the saline-alkali lands in Changling County, Zhenlai County and Da'an City of the western Jilin Province in 1980-2000 with the help of GIS. The results show that the saline-alkali land rather sharply increased in Da'an during 1995-2000; the main conversion processes in the three counties were from grassland to saline-alkali land and from saline-alkali land to grassland; and the typical shapes, spatial expansion speed and mode, and landscape attributes of the saline-alkali land were different in the three counties, which were closely related to local topography, predominant wind orientation, water resources distribution, etc. The corresponding spatial expansion mode was marginality in Changling, random in Zhenlai and more kernels in Da'an, respectively. Landscape attributes also responded to the spatial-temporal dynamic changes of the saline-alkali land and the landscape indices of Da'an fluctuated greatly. The frame of this research may provide fundamental reference for landscape analysis and give some suggestions for regional sustainable development. 展开更多
关键词 Tupu saline-alkali land GIS Jilin Province
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Seasonal Dynamics of Biomass under Different Land Use Patterns 被引量:3
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作者 徐霞 张智才 +1 位作者 张勇 田玉强 《Agricultural Science & Technology》 CAS 2010年第8期49-52,共4页
[Objective] The aim was to study seasonal dynamics of biomass under different land use patterns. [Methed] Aboveground biomass and underground biomass of plants under 3 different surface cover conditions of Stipa krylo... [Objective] The aim was to study seasonal dynamics of biomass under different land use patterns. [Methed] Aboveground biomass and underground biomass of plants under 3 different surface cover conditions of Stipa krylovii, Leymus chinensis and farmland were determined in growing season ( from May to October) of 2008. [ Result ] The aboveground biomass of Stipa krylovii, Leymus chinensis and farmland in August all reached the highest value, which of Stipa krylovii, Leymus chinensis and farmland was 287.91,117.05 and 193.59 g/m2, respectively. The total biomass of plant roots of the 3 plots in July all reached the highest value, which of Stipa krylovii, Leymus chinensis and farmland was 1 683.9, 1 601.9 and 513.9 g/m2, respectively. Leymus chinensis had the biggest biomass ratio of upper plant roots (0 - 15 cm) to lower plant roots (15 -30 cm), Stipa krylovii took second place, and farmland had the smallest one. ~ Conclusion The research provides theoretical basis for the ecological environment protection of ecological fragile area. 展开更多
关键词 Inner Mongolia grassland land use patters BIOMASS Seasonal dynamics
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Spatial-temporal Dynamics and Driving Forces of Land Development Intensity in the Western China from 2000 to 2015 被引量:17
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作者 HUANG Xin HUANG Xiaojun +2 位作者 LIU Mengmeng WANG Bo ZHAO Yonghua 《Chinese Geographical Science》 SCIE CSCD 2020年第1期16-29,共14页
The change in land development intensity is an important perspective to reflect the variation in regional social and economic development and spatial differentiation.In this paper,spatial statistical analysis,Ordinary... The change in land development intensity is an important perspective to reflect the variation in regional social and economic development and spatial differentiation.In this paper,spatial statistical analysis,Ordinary Least Squares(OLS),and Geographically weighted regression(GWR)methods are used to systematically analyse the spatial-temporal characteristics and driving forces of land development intensity for 131 spatial units in the western China from 2000 to 2015.The findings of the study are as follows:1)The land development intensity in the western China has been increasing rapidly.From 2000 to 2015,land development intensity increased by 3.4 times on average.2)The hotspot areas have shifted from central Inner Mongolia,northern Shaanxi and the Beibu Gulf of Guangxi to the Guanzhong Plain and the Chengdu-Chongqing urban agglomeration.The areas of cold spots were mainly concentrated in the Qinghai-Tibet Plateau,Yunnan,and Xinjiang.3)Investment intensity and the natural environment have always been the main drivers of land development intensity in the western China.Investment played a powerful role in promoting land development intensity,while the natural and ecological environment distinctly constrained such development.The effect of the economic factors on land development intensity in the western China has changed,which is reflected in the driving factor of construction land development shifting from economic growth in 2000 to economic structure,especially industrial structure,in 2015. 展开更多
关键词 construction land land development intensity spatial-temporal dynamic driving force the western China
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Monitoring Land Use Dynamics in Chanthaburi Province of Thailand Using Digital Remotely Sensed Images 被引量:12
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作者 SHENRUNPING I.KHEORUENROMNE 《Pedosphere》 SCIE CAS CSCD 2003年第2期157-164,共8页
A comprehensive method of image classification was developed for monitoring land use dynamics in Chanthaburi Province of Tailand. RS (Remote Sensing), GIS (Geographical Information System), GPS (Global Positioning Sys... A comprehensive method of image classification was developed for monitoring land use dynamics in Chanthaburi Province of Tailand. RS (Remote Sensing), GIS (Geographical Information System), GPS (Global Positioning System) and ancillary data were combined by the method which adopts the main idea of classifying images by steps from decision tree method and the hybridized supervised and unsupervised classification. An integration of automatic image interpretation, ancillary materials and expert knowledge was realized. Two subscenes of Landsat 5 Thematic Mapper (TM) images of bands 3, 4 and 5 obtained on December 15, 1992, and January 17, 1999, were used for image processing and spatial data analysis in the study. The overall accuracy of the results of classification reached 90%, which was verified by field check.Results showed that shrimp farm land, urban and traffic land, barren land, bush and agricultural developing area increased in area, mangrove, paddy field, swamp and marsh land, orchard and plantation, and tropical grass land decreased, and the forest land kept almost stable. Ecological analysis on the land use changes showed that more attentions should be paid on the effect of land development on ecological environment in the future land planning and management. 展开更多
关键词 image classification land use dynamics remote sensing tropical area
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Spatial structure optimization of mountainous abandoned mine land reuse based on system dynamics model and CLUE-S model 被引量:8
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作者 Linlin Cheng Haiyuan Sun +1 位作者 Ye Zhang Shaofeng Zhen 《International Journal of Coal Science & Technology》 EI 2019年第1期113-126,共14页
The mountainous abandoned mine land is often distributed in the fomi of fragmented patches. Therefore, it can greatly promote the reuse value of abandoned mine land and relieve the pressure of land demand to realize t... The mountainous abandoned mine land is often distributed in the fomi of fragmented patches. Therefore, it can greatly promote the reuse value of abandoned mine land and relieve the pressure of land demand to realize the rational reuse of abandoned mine land based on the future land use structure and spatial layout of mountainous area. In this paper, optimization of the spatial structure of mountainous abandoned mine land reuse is realized through the system dynamics model and CLUE-S model. Mentougou district, Beijing, China is selected as the research area. System dynamics model with feedback functions is constructed to simulate land use structure from 2011 to 2025, which is taken as the quanfiiative constraint on spatial structure optimization. CLUE-S model with neighborhood analysis function is applied to simulate future land use spatial structure. The simulation result layer is superimposed with the abandoned mine land distribution layer and the optimized spatial structure of abandoned mine land reuse then is determined, checked by reuse suitability evaluation. The result shows that abandoned mine land can be fully optimized as other land use types according to demand, and the reuse directions are water conservancy facilities land, urban land, rural residential land, tourism land, garden land, woodland and grassland. The trend of abandoned mine land reuse tend to be consistent with land use types of neighboring patches. This study can provide theoretical reference for the practices of mountainous abandoned mine land reuse. 展开更多
关键词 Mournainous abandoned MINE land REUSE System dynamics MODEL CLUE-S MODEL SPATIAL structure OPTIMIZATION
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The Effect of Land Degradation on Farm Size Dynamics and Crop-Livestock Farming System in Ethiopia: A Review 被引量:3
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作者 Assemu Tesfa Shigdaf Mekuriaw 《Open Journal of Soil Science》 2014年第1期1-5,共5页
Ethiopia is among the poorest countries in which poverty, land and resource degradation appear to feed off each other. The irony is that Ethiopia is a country with high biodiversity and distinctive ecosystems and the ... Ethiopia is among the poorest countries in which poverty, land and resource degradation appear to feed off each other. The irony is that Ethiopia is a country with high biodiversity and distinctive ecosystems and the natural resource base is critical to the economy and the livelihood of a high percentage of the population. Being the owner of varying agro ecology, the country’s agricultural production system had practiced for decades with a maximum potential. However, because of the presence of interrelated problems, the productivity had not sustained as its potential. From the interrelated problems, land degradation takes the first and challengeable problem in many countries. Land degradation refers to a temporary or permanent decline in the productive capacity of the land, or its potential for environmental management as a result;the long-term biological and environmental potential of the land has been compromised. Land degradation in the Ethiopian highlands (i.e. areas above 1500 m.a.s.l.) has been a concern for many years and is a great threat for the future that requires great effort and resources to ameliorate. It had adverse effect on lowering of livestock production by shrinking grazing land, the fertile soil types were washed and the grazing land was dominantly covered by unpalatable pastures and grasses which had low nutritive value and fertility for crop-livestock production system. In other cases, degradation induces farmers to convert land to lower-value uses;for instance, cropland converted to grazing land, or grazing lands converted to shrubs or forests. Equitable and secure access to land is a critical factor for the rural poor, especially livestock owners, who depend on agriculture and animal-related activities for their livelihood. Having secure access to land for agriculture and pastoral activities reduces their vulnerability and enhances their opportunities to invest in land for agriculture and livestock activities. Historical patterns of feudal ownership of land followed by government ownership and despite policy change uncertain status of land ownership. These land distribution and ownership patterns coupled with continuous fragmentations and degradation disrupt the balance between crop, livestock, and forest production. These things nowadays enforce Ethiopian farmers to put more land into crop production than working on livestock sector. Livelihoods are complex, dependent on animal and crop production based on land and water resources, with emerging market opportunities. And from year to year, the size of farms is getting minimized because of land degradation and segmentations, and these make a change in farm size dynamics and farming shift. Currently, there is a great scenario towards the land policy pattern and agricultural production system, which is the backbone of the country’s economy. Therefore, the aim of this paper is to review the effect of land degradation on farm size dynamics and crop-livestock production since the impact of these things is not well measured. 展开更多
关键词 Crop-Livestock FARMING System FARMERS Farm Size dynamics land Degradation
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Urban Dynamics and Emergence of New Centers in the Dakar Region (Senegal)
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作者 Mouhamadou Moustapha Mbacké Ndour Mohamed Lamine Ndao Alphousseyni Ndonky 《Journal of Geographic Information System》 2024年第4期227-243,共17页
Due to the status of the Dakar region as the former capital of AOF (French West Africa) and current capital of the Republic of Senegal, it is home to a very large part of the population and most of the socio-economic,... Due to the status of the Dakar region as the former capital of AOF (French West Africa) and current capital of the Republic of Senegal, it is home to a very large part of the population and most of the socio-economic, administrative and cultural activities on a very small area of the country (0.28%). This situation makes it a very attractive region and subject to strong land pressure. The objective of this article is to study past and current urban dynamics as well as changes in natural spaces, in order to identify new urban centers. The methodological approach consists in analyzing satellite images to understand the evolution of different forms of spatial occupation in the Dakar region, and to study population movement flows and urban forms in order to reveal new urban centers. The results of the study show that the Dakar urban space is characterized by diverse forms which express a heterogeneous set of spaces. They also revealed the emergence of new clusters between 1986 and 2016, notably Ngor, Grand Yoff, Parcelles Assainies in the North-West, and Keur Massar and the North of the communes of Rufisque in the eastern part of the Dakar region. 展开更多
关键词 Urban dynamics Movement Flows Urban Forms land Use DAKAR
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Effects of Microbial Fertilizers on Soil Improvement and Wheat Growth Characteristics in Saline-alkali Land
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作者 Gen SONG Ziru LI +12 位作者 Baohai ZHANG Zhenhua JIA Jirong CUI Dingxin GUO Lili HAN Yanhong WU Jianlong FENG Yan GAO Mingying LIU Chunguang SONG Guojia JI Changsong WANG Zhiwei ZHANG 《Agricultural Biotechnology》 2024年第4期76-81,共6页
[Objectives]This study was conducted to further enrich the research on saline-alkali land improvement,and explore the effects of biological bacterial fertilizers containing Bacillus subtilis and Bacillus velezensis HM... [Objectives]This study was conducted to further enrich the research on saline-alkali land improvement,and explore the effects of biological bacterial fertilizers containing Bacillus subtilis and Bacillus velezensis HM-3 in saline-alkali land improvement and crop growth promotion.[Methods]Wheat was planted in saline-alkali land in Huanghua City,Hebei Province,and a mixed application experiment was carried out using biological agents from Hemiao Biotechnology Co.,Ltd.[Results]Compared with the field of control check(CK),water-soluble salts and pH value in the experimental fields decreased,and living bacteria count in the soil increased.Meanwhile,the economic characters of wheat in the experimental fields showed excellent performance,with yields increasing by 39.09%and 27.49%compared with the CK.It could be seen that the application of biological bacterial fertilizers achieved obvious effects of improving saline-alkali soil and increasing wheat yield.[Conclusions]In this study,the effects of biological bacterial fertilizers on saline-alkali land and wheat growth characters were clarified,providing some technical support and theoretical guidance for wheat planting in Huanghua saline-alkali land. 展开更多
关键词 saline-alkali land Soil improvement WHEAT YIELD
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Landscape Dynamics and Driving Factors in Da’an County of Jilin Province in Northeast China During 1956-2000 被引量:1
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作者 WANG Zongming ZHANG Yubo +4 位作者 ZHANG Bai SONG Kaishan GUO Zhixing LIU Dianwei LI Fang 《Chinese Geographical Science》 SCIE CSCD 2008年第2期137-145,共9页
The landscape pattern of Da’an County, Northeast China has undergone significant changes since the 1950s as a result of climatic change and human activities. The aim of this paper is to quantitatively study landscape... The landscape pattern of Da’an County, Northeast China has undergone significant changes since the 1950s as a result of climatic change and human activities. The aim of this paper is to quantitatively study landscape pattern and its spatial dynamics of Da’an County at the landscape level over the nearly 50-year span. Patch dynamics were examined ac-cording to land use and land cover change processes built from a series of images, as well as topographic maps, and tem-poral patterns built from landscape pattern metrics. The transition matrix of landscape patch types and changes of various landscape metrics were applied. The results showed that, from 1956 to 2000, the landscape within the study area had un-dertaken a complicated evolution in landscape structure and composition. The outstanding characteristic is that sa-line-alkali land increased and grassland decreased. As some smaller patches amalgamated, the heterogeneity of patch de-creased. All those changes were the synthetic result of both climatic and anthropogenic influences, but the predominant factor was different in different parts. In the southern part of the study area, the landscape pattern changes resulted from the modification of climate obviously, while in the northern part, the landscape pattern changes were mainly caused by human activities, such as the conversion between farmland and saline-alkali land. This phenomenon showed that human activities played more important role in the north than in the south of Da’an County. 展开更多
关键词 landscape evolution land use change saline-alkali land Da'an County Northeast China
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Design and Dynamics Analysis of Anti-skid Braking System for Aircraft with Four-wheel Bogie Landing Gears 被引量:1
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作者 ZHANG Ming NIE Hong ZHU Rupeng 《Chinese Journal of Mechanical Engineering》 SCIE EI CAS CSCD 2011年第2期277-284,共8页
In asymmetric conditions,the movement and loads of left/right wheels or front/back wheels of the aircraft with multi-wheel or four-wheel bogie landing gears are inconsistent.There are few open literatures related to a... In asymmetric conditions,the movement and loads of left/right wheels or front/back wheels of the aircraft with multi-wheel or four-wheel bogie landing gears are inconsistent.There are few open literatures related to anti-skid braking system for multi-wheels due to technology blockade.In China,the research on multi-channel control and non-equilibrium regulation has just started,and the design of multi-channel control system for anti-skid braking,the simulation of asymmetry taxiing under braking are not studied.In this paper,a dynamics model of ground movement for aircraft with four-wheel bogie landing gears is established for braking simulation, considering the six-degree-of-freedom aircraft body and the movement of bogies and wheels.A multi-channel anti-skid braking system is designed for the wheels of the main landing gears with four-wheel bogies.The eight wheels on left and right landing gears are divided into four groups,and each group is controlled via one channel.The cross protection and self-locked protection modules are added between different channels.A multi-channel anti-skid braking system with slip-ratio control or with slip-velocity control is established separately.Based on the aircraft dynamics model,aircraft braking to stop with anti-skid control on dry runway and on wet runway are simulated.The simulation results demonstrate that in asymmetric conditions,added with cross protection and self-locked protection modules,the slip-ratio-controlled braking system can automatically regulate brake torque to avoid deep slipping and correct aircraft course.The proposed research has reference value for improving brake control effect on wet runway. 展开更多
关键词 anti-skid braking system four-wheel bogie landing gear multi-channel control dynamics model
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Analysis of Spatio-Temporal Dynamics of Land Use in the Bouba Ndjidda National Park and Its Adjacent Zone (North Cameroun) 被引量:2
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作者 José Elvire Boukeng Djiongo André Desrochers +3 位作者 Marie Louise Tiencheu Avana Damase Khasa Louis Zapfack éric Fotsing 《Open Journal of Forestry》 2020年第1期39-57,共19页
We evaluated the dynamics of land use in the Bouba Ndjidda National Park (BNNP) and adjacent areas, in northern Cameroon. Using a maximum likelihood supervised classification of satellite images from 1990 to 2016, cou... We evaluated the dynamics of land use in the Bouba Ndjidda National Park (BNNP) and adjacent areas, in northern Cameroon. Using a maximum likelihood supervised classification of satellite images from 1990 to 2016, coupled with field and a socio-economic survey, we performed a robust land-use classification. Between 1990 and 2016, the area included eight classes of land use, with the largest in 1990 being the woody savannah (42.9%) followed by the gallery forest (20.2%) and the clear forest (16.3%). Between 1990 and 1999, the gallery forest lost 64.8% of its area mostly to the benefit of woody savannahs. Between 1999 and 2016, the largest loss of area was that of the clear forest, which decreased generally by 43.2% in favor of woody savannah. Rates of increase of crop field areas were 59.6% and 78.8% respectively for the periods of 1990 to 1999 and 1999 to 2016 to the detriment of woody savannahs. We attribute the changes in land use observed mainly to the increasing human population and associated agriculture, overgrazing, fuelwood harvesting and bush fires. The exploitation of non-timber forest products and climatic factors may also have changed the vegetation cover. We recommend the implementation of farming techniques with low impact on the environment such as agroforestry. 展开更多
关键词 Remote Sensing SPATIO-TEMPORAL dynamics Bouba Ndjidda National PARK Vegetation COVER land Use
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Land Use and Land Cover Dynamics in the Urban Watershed of Kimemi River (Butembo/D.R.C) 被引量:2
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作者 Jonathan Ahadi Mahamba Gloire Kayitoghera Mulondi +1 位作者 Moïse Musubao Kapiri Walere Muhindo Sahani 《Journal of Geoscience and Environment Protection》 2022年第6期204-219,共16页
Changes in land use and land cover (LULC) influence hydrological processes in a watershed. This study analyses the dynamics of LULC in the Kimemi watershed from 1987 to 2021. GIS and remote sensing tools as well as la... Changes in land use and land cover (LULC) influence hydrological processes in a watershed. This study analyses the dynamics of LULC in the Kimemi watershed from 1987 to 2021. GIS and remote sensing tools as well as landscape pattern analysis were used to achieve this purpose. The results reveal that the LULC change is globally marked by an increase in the bare land and building at the expense of the low vegetation (grassland). Between 1987 and 2011, the bare land and buildings (Tg = 61.33%) and the woodland (Tg = 34.2%) classes increased, whereas the grassland class decreased (Tg = -39.5%). On the other hand, between 2011 and 2015, the bare land and building class still increased (Tg = 29.9%) while that of grassland and woodland decreased with Tg = -37.3% and Tg = -4.9%, respectively. Finally, the dynamics observed from 2015 to 2021 is marked by small changes between classes with Tg values of 2.1%, 1.9% and -8.9%, respectively, for the bare land and building, grassland and woodland classes, respectively. The main spatial transformation processes observed are creation and dissection for the bare land and building class, and the grassland class respectively. In particular, the woodland class underwent the creation process between 1987 and 2011 before undergoing attrition (2011-2015-2021). Reduced vegetated areas give rise to new planning decisions to mitigate the hydrological risks that could result from this situation. 展开更多
关键词 land Use and land Cover dynamics WATERSHED Kimemi River Butembo
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The integration of nitrogen dynamics into a land surface model. Part 1: model description and site-scale validation 被引量:2
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作者 YANG Xiujing DAN Li +5 位作者 YANG Fuqiang PENG Jing LI Yueyue GAO Dongdong JI Jinjun HUANG Mei 《Atmospheric and Oceanic Science Letters》 CSCD 2019年第1期50-57,共8页
Nitrogen cycling has profound effects on carbon uptake in the terrestrial ecosystem and the response of the biosphere to climate changes.However,nutrient cycling is not taken into account in most land surface models f... Nitrogen cycling has profound effects on carbon uptake in the terrestrial ecosystem and the response of the biosphere to climate changes.However,nutrient cycling is not taken into account in most land surface models for climate change.In this study,a nitrogen model,based on nitrogen transformation processes and nitrogen fluxes exchange between the atmosphere and terrestrial ecosystem,was incorporated into the Atmosphere–Vegetation Interaction Model(AVIM)to simulate the carbon cycle under nitrogen limitation.This new model,AVIM-CN,was evaluated against site-scale eddy covariance–based measurements of an alpine meadow located at Damxung station from the FLUXNET 2015 dataset.Results showed that the annual mean gross primary production simulated by AVIM-CN(0.7073 gC m^-2 d^-1)was in better agreement with the corresponding flux data(0.5407 gC m^-2 d^-1)than the original AVIM(1.1403 gC m^-2 d^-1)at Damxung station.Similarly,ecosystem respiration was also down-regulated,from 1.7695 gC m^-2 d^-1 to 1.0572 gC m^-2 d^-1,after the nitrogen processes were introduced,and the latter was closer to the observed vales(0.8034 gC m^-2 d^-1).Overall,the new results were more consistent with the daily time series of carbon and energy fluxes of observations compared to the former version without nitrogen dynamics.A model that does not incorporate the limitation effects of nitrogen nutrient availability will probably overestimate carbon fluxes by about 40%. 展开更多
关键词 Coupled carbon and nitrogen dynamics nitrogen limitation land surface model carbon–nitrogen–water cycles
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Effects of precipitation changes on the dynamics of sparse elm woodland in Northeastern China
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作者 Yi TANG Carlos Alberto BUSSO 《BIOCELL》 SCIE 2018年第2期61-66,共6页
Elm(Ulmus pumila L.)is the dominant tree species in the sparse elm woodland,the original vegetation in the Horqin Sandy Land.The effects of changes in precipitation on U.pumila trees have not been fully studied.We det... Elm(Ulmus pumila L.)is the dominant tree species in the sparse elm woodland,the original vegetation in the Horqin Sandy Land.The effects of changes in precipitation on U.pumila trees have not been fully studied.We determined a dynamic model by considering the five stages in the U.pumila life cycle,i.e.seed,seedling,and juvenile,mature and over-mature tree stages.The effects of changes in precipitation on population density and age structure were then evaluated.Population density,after averaging all study developmental morphology stages,ranged from 16.67 individuals/m2 to 25.01 individuals/m2 under a mean annual precipitation(MAP)of 80%to 120%,respectively.This suggests that population density could increase as MAP also increased.The proportion of seedlings,and juvenile,mature and over-mature trees were 95.23%,4.58%,0.19%and 0.01%,respectively,under all precipitation levels.This indicates that precipitation had little effects on the developmental stages of the studied U.pumila populations in the Horqin Sandy Land.Additional water supply might be provided in addition to the natural rainfall that occurs in the region,for contributing to maintain U.pumila population density in the Horqin Sandy Land. 展开更多
关键词 Population density PRECIPITATION Semi-arid lands System dynamics model
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Land Use and Land Management during the Past Century Determine Mangrove Dynamics in Northwestern Puerto Rico: the Case of the Maracayo Mangrove
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作者 Mónica Salazar-Ortiz Elvira Cuevas 《Journal of Environmental Science and Engineering(B)》 2017年第12期593-623,共31页
Political and economic decisions have determined throughout the history of Puerto Rico land use for agriculture, livestock and urban sprawl. Knowing this, this study is imperative to understand how these changes caus... Political and economic decisions have determined throughout the history of Puerto Rico land use for agriculture, livestock and urban sprawl. Knowing this, this study is imperative to understand how these changes caused by the various uses and management affected adjoining wetlands. It is hypothesized that these changes affected the hydrology of the area, resulting in increased salinity, providing the right niche for the development of current mangrove. The resources used were aerial photographs, oral history, a report done in 1979 by the Department of Natural and Environmental Resources of the Government of Puerto Rico and analyses of salinity, pH and conductivity of soils in three different sites. The conclusion of this study was that the wetland underwent changes in ecosystem composition by ambitious elimination of sand dunes due to hydrological changes and marine effects. The oral history confirms the presence of springs in the past and present. Salinity intrusion was documented in those springs in the 1979 report due to land use change and elimination of sand dunes, changing the habitat, therefore allowing a mangrove community to be established. The continuity of ecophysiological and hydrogeological studies of the area will allow for a predictive understanding of how the mangrove wetland will continue developing. 展开更多
关键词 GIS MANGROVE WETland land use dynamics.
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Dynamics of Land Salinization in the Commune of Fimela (Fatick, Senegal) from 1973 to 2020
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作者 Khadidiatou Ba Hyacinthe Sambou +1 位作者 Binette Ndiaye Assane Goudiaby 《Journal of Geographic Information System》 2023年第1期19-34,共16页
In Senegal, the agricultural sector remains a major component of the economy and national growth. As the main subsistence activity for 60% of the population, agricultural activity is essential to reduce poverty and en... In Senegal, the agricultural sector remains a major component of the economy and national growth. As the main subsistence activity for 60% of the population, agricultural activity is essential to reduce poverty and ensure food security for the population. In this context, land degradation is a major constraint. In the Fatick region, in the commune of Fimela, land salinization is a worrying environmental problem. The purpose of this study is to understand the dynamics of soil salinization in Fimela in the context of climate change that tends to modify the evolution of landscapes. It required direct observations in the field, socio-economic surveys based on a questionnaire administered in six (6) villages. The processing of the data from these surveys was carried out with Sphinx software for the extraction of data in numerical form and SPSS to carry out the correlations between the collected variables. Excel was also used to perform calculations and make tables and graphs. In addition, the acquisition and processing of Landsat multi-spectral satellite images from 1973, 1988 and 2020 allowed us to observe the evolution of landscape units according to determining climatic events such as drought. The areas of tans have experienced a positive evolution during the period 1973-2020 with an increase of 163.11 hectares or an evolution rate of 7.47%. The localities most affected are Ndangane, Fimela, Djilor, Simal and the villages of the Mar Islands. The overall dynamics of cultivable land are marked by a decline with a rate of change of −18%. Despite the multiple reforestation campaigns, the mangrove has recorded a continuous decrease of 54.58% or a loss estimated at 5335.59 ha during the period 1973-2020. Finally, the analysis of the results of our study shows that land salinization is a determining element of the dynamics of land use and deteriorates the already precarious living conditions of rural populations and compromises the future of the agropastoral production system. 展开更多
关键词 dynamics land Salinization Fimela Senegal
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International Conference on Land Use / Cover Change Dynamics
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《Journal of Geographical Sciences》 SCIE CSCD 2001年第1期121-,共1页
Organized by: Beijing Normal University, National Natural Science Foundation of China Hosted by: Institute of Resources Science, Beijing Normal UniversityKey Laboratory of Environmental Change and Natural Disaster, Mi... Organized by: Beijing Normal University, National Natural Science Foundation of China Hosted by: Institute of Resources Science, Beijing Normal UniversityKey Laboratory of Environmental Change and Natural Disaster, Ministry of Education of ChinaTopics:1) Detecting and monitoring LUCC2) Temporal-spatial characteristics in LUCC3) Driving model for LUCC4) Forecasting and modeling LUCC 5) Phenological and biochemical response on LUCC6) Regional LUCC and microclimate 7) LUCC in the context of global change8) Impact of global change on the sustainable land-use modelingAbstract submission: The official language of this conference is English. We invite papers written in English and an abstract of less than one page of standard A4 size to the Conference Secretariat by Apr 15, 2001. Registration Fee: 280 US$ (300 US$ after July 15, 2001)Add:No. 19, Xinjiekouwai Street, 100875, Institute of Resources Science, Beijing Normal University, Beijing, ChinaTel:86-10-62207656 or 62209024 Fax:010-62208178http:// 202.112.93.50/LUCCD2001/index.htmlE-mail: Pwang@bnu.edu.cn Cyh@bnu.edu. 展开更多
关键词 LUCCD’2001 First Circular Announcement International Conference on land Use/Cover Change dynamics
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Drivers of Land Cover Dynamics for Pugu and Kazimuzumbwi Forest Reserves in Kisarawe, Tanzania
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作者 Makarius Victor Mdemu Marco Mathias Burra 《Open Journal of Forestry》 2016年第5期348-360,共14页
Forests that are close to growing urban centres have been subject to constant deforestation and degradation from various factors. This study assesses the drivers of land cover dynamics in Pugu and Kazimzumbwi forest r... Forests that are close to growing urban centres have been subject to constant deforestation and degradation from various factors. This study assesses the drivers of land cover dynamics in Pugu and Kazimzumbwi forest reserves in the context of urban and peri-urban expansion of Dar es Salaam for the past three decades. The study adopted review of relevant literature and household survey from three settlements surrounding the forest reserves. One hundred and fifty (150) households were collected from Buyuni, Chanika and Masaki in Ilala and Kisarawe and administered with semi-structured questionnaire to collect information on migration, use of forest products by communities and perception on climate change and variability. SPSS computer program was used to analyse the questionnaire data while tables and graphs were adopted for presentation of the results. Rural-urban and internal urban migration in Dar es Salaam was identified as one of the primary drivers of land cover dynamics in peri-urban areas and adjoining environments. The migration was intensified by push drivers which include urban growth, market of land and reliance on forest product among community members as source of their livelihoods. The increased rainfall variability accompanied with high temperature has contributed to frequent droughts which compromises rainfed agriculture. Thus, the successful conservation of the forest will require strengthened enforcement of protection measures supported with introduction of alternative livelihood strategies for majority of poor community members. 展开更多
关键词 Climate Change and Variability DRIVER Forest Reserve land Cover dynamics PERI-URBAN
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Land Use Land Cover Dynamics and Farmland Intensity Analysis at Ouahigouya Municipality of Burkina Faso,West Africa
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作者 Oble Neya Tiga Neya +4 位作者 Akwasi.A.Abunyewa Benewinde J.-B.Zoungrana Hypolite Tiendrebeogo Kangbeni Dimobe Joel Awouhidia Korahire 《American Journal of Climate Change》 2020年第1期23-33,共11页
Sahel zone has been reported as one of the most vulnerable regions to climate change, so serious attention must be paid to this zone by researchers and development actors who are interested in environmental-human dyna... Sahel zone has been reported as one of the most vulnerable regions to climate change, so serious attention must be paid to this zone by researchers and development actors who are interested in environmental-human dynamics and interactions. The aim of this study was to bring more insight into the impact of actions aiming at reducing land degradation, regreening the Sahel, stopping population migration and reducing the pressure on land in the Sahelian zone. The study focused on farmland dynamic in Ouahigouya municipality based on remote sensing data from 1986 to 2016 using intensity analysis. The annual time interval change was 0.77% and 2.46% for 1986-2001 and 2001-2016, respectively. Farmlands gained from mixt vegetation, water bodies and from bar lands. Mixed vegetation and water bodies were both active during both intervals while the other land use such as woodland and bar land were dormant. Combining land use land cover analysis and intensity analysis was found to be effective for assessing the differentiated impact of the various land restoration actions. 展开更多
关键词 Farmland dynamics Intensity Analysis land Use land Cover Vegetation West Africa Climate Smart Agriculture
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