退耕还林还草政策影响下米脂县银州镇土地利用变化研究

以米脂县银州镇1986年和2006年两期TM影像及1996年土地利用现状图为基础,结合GIS空间分析软件和遥感软件,分析了1986-1996年、1996-2006年以及1986-2006年的土地利用时空变化.研究表明,1986-1996年期间,土地利用变化表现为水域、林地和草地减少,耕地和其它用地增加,其中尤以耕地面积变化最为显著,减少的林地和草地主要转化为耕地;1996-2006年期间,主要的土地利用变化表现为水域、耕地和其它用地减少,林地和草地增加.由于受到退耕还林还草政策的影响,耕地减少主要表现为转化成林地和草地.总体上看,1986-2006年期间,银州镇土地利用变化显著,主要表现为水域、林地和耕地面积减少,草地和其它用地面积增加,水域、林地和耕地主要转化为草地.1986-2006年土地利用变化主要发生在粱峁地上,有部分无定河两岸的水浇地转化为其它用地.退耕还林还草工程在改善当地生态环境方面虽取得了一定效果,但生态环境的保护和恢复仍是一个长期的任务.     

生态建设重点区域土地利用变化及驱动因素分析——以潮河流域为例

以密云水库的重要水源地和生态建设重点区域——潮河流域为研究区,基于GIS技术,分析了20世纪80年代中后期到2005年流域的土地利用/覆被变化;在此基础上,构建了土地利用变化驱动力指标体系,对流域土地利用变化的驱动力进行了主成分分析,分析了1981—2005年政策、经济、人口、科技进步等驱动因素对该流域土地利用变化的影响。结果表明:潮河流域的土地利用类型以林地为主,20世纪80年代中后期到2005年,流域林地、草地的变化最为显著,其中林地面积增加最多,草地面积则大幅减少;政策因素是影响该流域土地利用格局变化的主导因素。     

Land use/cover change and landscape fragmentation analysis in the Bindura District,Zimbabwe

Rapid land use/cover change and landscape fragmentation is occurring in many countries in central and southern Africa, as a result of colonial imbalances in land distribution, demographic pressure, agricultural expansion, government policies and environmental factors such as drought. This study analysed the dynamics of land use/cover and land degradation as revealed in landscape fragmentation in the Bindura District of Zimbabwe based on Landsat data for 1973 and 2000. A hybrid supervised/unsupervised classification approach coupled with GIS analyses was employed to generate land use/cover maps from which various class level landscape metrics were calculated using FRAGSTATS®, in order to analyse landscape fragmentation. The results show that agriculture, mixed rangeland, settlements, bareland and water increased, while woodland areas decreased. Consequently, the landscape became more highly fragmented as indicated by an increase in the patch number and a decrease in the mean patch size (MPS) of the woodland and mixed rangeland classes. This suggests that anthropogenic activities driven by agricultural expansion were the main causes of landscape fragmentation, leading to landscape degradation in the study area. Copyright © 2006 John Wiley & Sons, Ltd.     

Spatio‐Temporal Patterns of Land Use/Cover Changes Over the Past 20 Years in the Middle Reaches of the Tarim River,Xinjiang, China

The interaction between land use/cover change and landscape pattern is pivotal in research concerning global environmental change. This study uses three different Landsat images of 1989, 1998 and 2009 to study the land use/cover and landscape pattern changes in the middle reaches of the Tarim River basin. envi ®, erdas ®, ArcGIS ® and fragstats ® software were used to analyse the land use/cover changes. The objectives of study were to map and study the changes in land use/cover and landscape pattern, and propose some possible factors in making the land use/cover changes from 1989 to 2009. Seven different types of land use/cover are analysed, and the results are listed in tables. From 1989 to 1998, the percentage of farmland, slight–moderate saline land, heavy saline land and water areas have increased; woodland, desert and the undeveloped land have decreased. From 1998 to 2009, farmland, heavy saline land and the undeveloped land have increased; the other types of land use/cover have decreased. The gravity centre of each land use/cover types has shifted. The farthest shifting of the gravity centre was heavy saline land, which occurred between 1989 and 1998. The transformation and changes of land use/covers and landscape occurred more frequently from 1989 to 2009. Other types of land use and land cover changes to saline land have increased, which implied that a serious salinization took place in the Tarim Basin. The results from this study would show the adverse environmental changes (e.g. salinization and desertification) and they can be used for future sustainable management of land resources. Copyright © 2013 John Wiley & Sons, Ltd.     

土地利用变化对塔里木河中游荒漠林地动态的影响

[目的]探究塔里木河中游荒漠绿洲过渡带——肖塘地区的土地利用动态变化特征及其对荒漠林地动态格局的影响,为该区域土地资源合理利用以及荒漠林资源保护提供理论依据。[方法]根据肖塘地区1973—2010年4期遥感影像解译数据进行荒漠林地动态变化分析。[结果]荒漠林地从1973年占整个研究区面积的21.9%到2010年的16.9%,成为研究区变幅最大的土地利用类型。1973—2010年荒漠林地面积减少了13.19%,主要转变为农田,而且其年变化速率不断增大。[结论]近40a来,随着人类对肖塘地区持续的水土开发,研究区内荒漠林地处于持续退化的状态。天然植被的退化会进一步对该区域的生态安全构成威胁。     

Land use,deforestation and reforestation in the Zambian Copperbelt

Temporal and spatial changes in land use, vegetation cover, deforestation and reforestation in the Zambian Copperbelt were studied using a combination of aerial photograph analysis, literature review and inquiries among relevant government institutions. The study showed that between 1937 and 1984 loss of natural woodlands in the Copperbelt of Zambia (total area of Copperbelt: 9,615 km²) amounted to 41 per cent woodland area (8,419 km²). The major causes of this deforestation are woodfuel collection (for firewood and charcoal), cultivation and replacement of natural woodland with forest plantations. These accounted for 38 per cent, 37 per cent and 15 per cent of the total deforestation, respectively. Before 1962 the copper mining industry used large quantities of firewood to generate electricity and this resulted in the loss of 150,413 ha of woodland between 1937 and 1961. When the mining industry switched to hydroelectricity, urban households became the major users of woodfuel. The urban population in the Copperbelt increased from 0.412 million in 1960 to 1.400 million in 1984 and its consumption of woodfuel led to the deforestation of at least 89,436 ha between 1962 and 1984. Deforested areas are left to regenerate naturally. However, due to poor management about 34 per cent of the area deforested before 1962 has failed to regenerate. Although 50,200 ha have been reforested with exotic trees, only 5,020 ha of this is on land previously deforested. Thus only about 10 per cent of reforestation efforts have contributed to the rehabilitation of damaged land. Ninety per cent of the reforestation has actually replaced standing indigenous woodland. Uncontrolled bushfires have destroyed forest plantations and have also caused the failure of woodland regeneration in deforested areas. These observations indicate that if forest resources in the Copperbelt of Zambia are to be properly managed it will be necessary:

• 1 to effectively regulate land use changes and;
• 2 to control bushfires.

     

Continuing land degradation: Cause–effect in Ethiopia's Central Rift Valley

The Central Rift Valley (CRV) is one of the most environmentally vulnerable areas of Ethiopia. Most of the lowland in the CRV is arid or semiarid, and droughts occur frequently. We studied the dynamics of land use and cover and land degradation by analyzing Landsat data from 1973, 1985, and 2006 using Geographic Information Systems and remote sensing techniques. The analysis revealed that in the last 30 years, water bodies, forest, and woodland decreased by 15·3, 66·3, and 69·2 per cent, respectively; intensive cultivation, mixed cultivation/woodland, and degraded land increased by 34·5, 79·7, and 200·7 per cent. The major causes of land use and cover change (LUCC) and land degradation in the area were population and livestock growth in regions of limited resources, unsustainable farming techniques, the Ethiopian land tenure system and poverty. Lake level and area decline, and accelerated land degradation are the major environmental impacts of LUCC observed in the CRV. The environmental and socio‐economic consequences of LUCC and land degradation are far‐reaching. As a result of the expansion of land degradation over time, agricultural productivity has decreased and worsened food insecurity (shortages) and poverty in the Ethiopian CRV. In addition, if current trends in LUCC continue, Lake Abiyata will dry up by 2021. A detailed study of the degradation amount in relation to soil erosion, sediment yield to the lakes and catchment characteristics should be made using adaptable models; so as to guide the implementation of comprehensive and sustainable land use management by giving more attention to erosion prone areas. Copyright © 2010 John Wiley & Sons, Ltd.     

基于RS和GIS的土地利用/覆被动态变化监测——以九龙县为例

区域土地利用动态监测分析是土地利用研究的重要组成部分,可以为区域土地的合理利用和政府部门的宏观调控提供支持依据。为了掌握土地利用状况及动态变化的信息和趋势,对土地利用动态平衡的调控和生态环境保护提供辅助手段,以九龙县为研究区域,利用1994年、2000年和2007年三期的Landsat卫星TM影像,采用遥感(RS)技术和地理信息系统(GIS)技术,对九龙县13a来土地利用变化进行了动态监测分析,通过各年土地利用分布变化图,土地利用转移矩阵,研究了九龙县各种土地利用类型变化的情况。结果表明:林地净增加了170.96km2,其中169.94km2草地净增为林地,1.9km2旱地净增为林地,说明林地主要是由旱地和退化草地转化而来;冰川净增18.67km2,裸地净减6.14km2,说明天然林保护工程和退耕还林工程对当地的水土保持起到了显著成效。利用马尔柯夫模型预测了九龙县未来几十年来土地利用变化的趋势:林地面积将会以每13年递增2%的速度变化,冰川面积将会以每13年递增1.5%的速度变化,说明未来九龙县的生态环境将会是良性发展,为九龙县生态环境治理提供了科学依据。     

Eucalypt establishment in agricultural landscapes and implications for landscape-scale restoration

In south-eastern Australia large-scale re-establishment of woody vegetation is required to halt loss of biodiversity, land degradation and dryland salinisation. Revegetation is often undertaken via intensive replanting by tube-stock or seed although such methods are costly and can have limited biodiversity benefits. Regeneration from naturally dispersed seed is an alternative and cost-effective method of revegetation. Describing the relationships between broad-scale patterns of natural regeneration, landscape characteristics, climate and current and historical land use could assist in the development of regional revegetation strategies. In this paper we describe the results of a survey of eucalypt regeneration across 519 sites in grassy dry forests and grassy woodlands of central Victoria, Australia. Eucalypt regeneration was observed in 27% of all sites. The probability of eucalypt regeneration was reduced by intensive past land use (cultivation), regular livestock grazing, increasing distance to remnant trees and high cover of exotic annual vegetation. Even when these factors were taken into account, public land was predicted to have higher probabilities of supporting regeneration suggesting that a long-history of agriculture can limit future recruitment even when grazing is removed. Although the highest probability of regeneration was observed in ungrazed sites, regeneration also occurred under intermittent grazing regimes. Natural regeneration has potential to make considerable contributions to future tree cover in these landscapes. Scenario testing at three farms suggests that under current patterns of tree cover (2.7%), 40% of the total area has a high probability of supporting natural regeneration in the absence of livestock grazing. However, due to paddock tree decline this could be reduced to 18% of total farm area if no management action is taken in the next 30 years.     

陕北黄土高原土地利用/覆盖变化及生态效应评价

基于1997年和2006年两期遥感影像获得陕北黄土高原地区土地利用变化数据,结合 RS和GIS技术,对陕北黄土高原土地利用/覆盖变化特征进行了分析.并采用生态服务价值的方法对陕北黄土高原土地利用变化的生态效应进行了综合评价.结果表明,1997-2006年,陕北黄土高原利用类型发生了显著变化,该区50.37%的耕地转换成为林地和草地,总体生态服务价值量显著增加7.67×106元,年增长率为0.2%,整体生态环境指数有所提高从0.145增长到0.157,土地利用/覆盖变化整体生态贡献指数变化明显,整体贡献指数为1.239,生态环境质量明显改善,表明退耕还林以来陕北黄土高原地区整体生态环境向着健康方向发展.     

松嫩平原西部地区土地利用/覆被变化的驱动力分析

利用1986年和2000年两期TM影像资料,在空间图形库系统支持下全面分析了松嫩平原西部地区土地利用/覆被数量变化和土地利用空间格局变化,揭示了近15年来研究区土地利用时空变化特征.表现为耕地、盐碱地从整体上呈现集中化,林地、草地不断破碎化.耕地与草地、草地与盐碱地空间相邻度增大,草地开垦和土地盐碱化日益严重.对不同经济类型区即农区、半农半牧区和牧区土地利用变化的社会经济因素的区域相似性和差异性分析表明,人口的压力、落后的畜牧业和经济利益驱动是近15年该区土地利用变化的主导因素.     

Land Cover Transition in Northern Tanzania

Land conversion in sub‐Saharan Africa has profound biophysical, ecological, political and social consequences for human well‐being and ecosystem services. Understanding the process of land cover changes and transitions is essential for good ecosystem management policy that would lead to improved agricultural production, human well‐being and ecosystems health. This study aimed to assess land cover transitions in a typical semi‐arid degraded agro‐ecosystems environment within the Pangani river basin in northern Tanzania. Three Landsat images spanning over 30 years were used to detect random and systematic patterns of land cover transition in a landscape dominated by crop and livestock farming. Results revealed that current land cover transition is driven by a systematic process of change dominated by the following: (i) transition from degraded land to sparse bushland (10·8%); (ii) conversion from sparse bushland to dense bushland in lowland areas (6·0%); (iii) conversion from bushland to forest (4·8%); and (iv) conversion from dense bushland to cropland in the highlands (4·5%). Agricultural lands under water harvesting technology adoption show a high degree of persistence (60–80%) between time slices. This suggests that there is a trend in land‐use change towards vegetation improvement in the catchment with a continuous increase in the adoption of water harvesting technologies for crop and livestock farming. This can be interpreted as a sign of agricultural intensification and vegetation regrowth in the catchment. Copyright © 2015 John Wiley & Sons, Ltd.     

基于遥感的10年间龙口市土地利用动态变化分析

对1992年6月、2002年6月两个时期的陆地卫星影像，采用监督分类和人机交互解译相结合的方法完成土地利用类型的计算机解译，定量分析了龙口市10年间土地利用的变化特征。结果表明：研究时段内园地、水浇地、水体，林地面积都有不同程度的减少；城乡用地、旱地、草地面积增加，其中城乡用地增幅最大；土地利用转换类型复杂多样，转换比例相对较大，说明龙口市土地利用方式受人为活动和经济发展影响强烈。     

贵州岩溶峡谷地表覆盖变化的地形分异特征

岩溶峡谷是典型的喀斯特生态脆弱区,研究其地表覆盖变化对山区生态保护和国土资源空间优化具有重要意义。以贵州境内岩溶峡谷为研究区,选取2000—2020年地表覆盖数据,提取海拔、坡度、坡向三种地形因子,探究其地表覆盖变化及地形分异特征。得出以下结论:(1)2000—2020年研究区各类地表覆盖面积变化差异明显,林地、草地、水域、建设用地面积增加,耕地面积减少;(2)研究时段内随着海拔上升,研究区耕地面积呈现上升-下降-上升-下降的变化趋势;林地面积总体呈现先上升后下降趋势,峰值大致在1800～2200 m;草地和建设用地面积均存在两个相对高值区,分别出现在1200～1400 m和2200～2400 m、1200～1400 m和1800～2000 m;水域面积在小于800 m、2000～2200 m相对较高;(3)随着坡度上升,研究区耕地、林地和草地面积呈现先上升后下降趋势,分别在10°～15°、15°～20°、10°～15°出现最高值;建设用地面积随坡度增加总体呈现下降趋势;(4)在随着坡向变化中,研究区耕地、林地、草地、建设用地面积在无坡向地区分布较少;2020年建设用地面积在西南坡分布...     

Land‐use and cover changes (1988–2002) around budongo forest reserve,NW Uganda: implications for forest and woodland sustainability

Land‐use and cover changes around Budongo Forest Reserve (BFR) were analysed from multi‐temporal LandSat images (1988 and 2002) and associated field‐based studies in 2003–2004. Three major land‐use and cover classes: forest/woodland, sugarcane plantations and grassland/shifting‐cultivation/settlements were clearly discriminated. The area under sugarcane cultivation increased over 17‐fold, from 690 ha in 1988 to 12729 ha in 2002, with a concomitant loss of about 4680 ha (8·2 per cent) of forest/woodland, mainly on the southern boundary of BFR. Land‐use and cover changes were a result of (a) agricultural expansion, (b) increasing human population, exacerbated by large influxes of refugees, (c) conflicts of interest and political interference in the management of BFR and (d) unclear land tenure. Agriculture is the main land‐use practice and source of income to local people, with commercial sugarcane and tobacco as the primary cash crops. Individual smallholder sugarcane plantations covered distances ranging from 30 to 1440 m along the BFR edge, with no buffer zone, resulting in direct conflicts between farmers and forest wild animals. There is an ever‐increasing need for more land for agricultural expansion, resulting in continued loss of forest/woodland on private/communal lands and encroachment into BFR. This unsustainable agricultural expansion and the local people's perception of BFR as an obstacle to agriculture, threatens the conservation of its threatened wild plants (e.g. Raphia farinifera) and the endangered chimpanzees. Therefore, their sustainable management for both development and conservation will require strong and incorruptible institutions that will seek a balance between resource exploitation and conservation. Copyright © 2008 John Wiley & Sons, Ltd.     

1999-2009年青海省德令哈市土地利用/覆盖变化特征

以1999年的ETM数据和2009年的矢量数据为数据源,在RS和GIS技术的支持下,分析了青海省德令哈市1999-2009年土地利用/覆盖的时空变化特征,并借助马尔科夫模型,预测了德令哈市未来20 a的土地利用/覆盖演变趋势。结果表明,德令哈市土地利用类型以草地为主。在1999-2009年这10 a中,草地面积减少最多,减少部分主要退化成未利用地;未利用地减少面积仅次于草地,减少部分主要转化成林地;耕地减少面积位居第3,减少部分主要转化成林地;林地增加面积最多,主要来自耕地和未利用地的转化;耕地的空间动态度最大,其次为林地。在未来20 a中,德令哈市耕地和草地的面积会持续减少,林地和建设用地的面积将继续增加。     

多源土地覆被产品在长三角地区的一致性分析与精度评价

土地覆被数据是全球环境问题,人类活动对生态系统影响评估等相关研究的重要数据源。近年来国内外生产了众多全球尺度或国家尺度上的土地覆被数据集,这些数据集在应用于特定区域研究时精度的可靠性以及多源数据集间的一致性对数据集的选择有着重要意义。该研究以长三角为研究区域,采用混淆矩阵、构成相似性分析和空间一致性分析等方法,对CCI_LC、FROM-GLC、GLC_FCS30、GLCNMO、GlobeLand30和CGLS_LC6种土地覆被数据集进行了基本精度验证及一致性分析,并探讨了面向不同用户需求的土地覆被数据产品的适用性。结果表明:CCI_LC、FROM-GLC、GLC_FCS30、GLCNMO、GlobeLand30和CGLS_LC在长三角地区的总体精度分别为76.89%、78.42%、84.67%、74.26%、80.61%和85.43%;产品间土地覆被类型面积估算的相关系数均大于0.9;FROM-GLC、GLC_FCS30和GlobeLand30三套产品对长三角地区65.51%的土地分类有完全一致性,产品间一致性分别为72.23%、77.99%和76.41%。6种产品对于广泛分布且占研究区大部分面积的耕地、林地、水体和建设用地具有较好的分类精度,湿地、裸地、灌丛和草地分类结果较弱,需要辅助其他数据产品使用。结合地形地貌分析来看,长三角地区土地覆被分类精度整体受地形起伏影响较小,但丘陵密布的浙江省的部分区域受地形影响出现了分类不稳定的情况。从城市发展的角度看,长三角地区土地覆被分类精度受到城市经济发展活跃程度影响。面向用户应用需求来看,耕地类型上CGLS_LC数据具有最优表现,林地和建设用地类别上GLC_FCS30和CGLS_LC具有相近的优秀表现,而水体类别则是FROM-GLC数据更具有优势。     

定西半干旱地区生态环境的遥感动态监测分析

对定西地区的定西县、渭源县、陇西县和通渭县的生态环境进行监测。以 1990年和 2 0 0 0年 2期TM数字图像为主要信息源 ,进行屏幕目视解译 ,取得了初步的本底数据。建筑交通及矿区用地增长率为14 .97% ;农业用地增长率为 8.0 2 % ;林地增长率为 11.2 3% ;其它如河滩地、宜林草荒地则相应有所减少。定西地区经过 10 a的发展 ,土地利用和土地覆盖日趋合理 ,但还存在诸如土地利用率不高 ,农业用地比重过大 ,畜牧业用地比重太小 ,以及造林面积大 ,而存林面积小 ,树木成活率低 ,退耕还林还草力度不够等问题。通过对监测结果的分析 ,说明了遥感技术在定西这一特殊地区土地利用 /植被覆盖动态监测中已被有效地应用 ,同时有针对性的提出一些合理化建议 ,以期有利于项目区土地利用和植被覆盖的合理化     

近25 a来渭-库绿洲土地利用/覆被变化及其影响因素

[目的]对渭干河—库车河三角洲绿洲土地利用/覆被变化特征及其驱动因素进行研究,为维护绿洲生态系统健康、稳定提供依据。[方法]利用研究区1989,2001,2013年Landsat TM/ETM+的影像数据,采用动态度模型及转移矩阵等方法,深入分析该绿州土地利用/覆被变化特征,并结合气候因子、人口与经济要素分析其变化原因。[结果](1)近25a来该绿洲土地利用/覆被类型没有发生变化,但各类型的面积及所占比例都发生了较大变化。(2)研究期内,各地类面积呈二增四减趋势:耕地面积净增114.52%,主要是由草地及其他地类转化而来;盐碱地面积增加66.11%,林地、草地、水体与其他地类的面积均有所减少。[结论]近25a来,该绿洲土地利用/覆被变化明显,其中,林地、草地、水体及盐碱地受自然因素主导,而耕地与其他地类则受人口和经济因素影响。