Application of Landsat satellite imagery to monitor land‐cover changes at the Athabasca Oil Sands,Alberta, Canada

A major advantage of satellite remote sensing is that the imagery acquired provides a synoptic view of the landscape. Thus, repeat coverage by the satellite on a regular basis permits the detection of changes in land‐cover over time. This study demonstrates the application of remote sensing technology to the monitoring of mining activities at the Athabasca Oil Sands region of Alberta, Canada. First, we describe the techniques used to match a time sequence of Landsat imagery, both spatially and spectrally, to ensure that the spectral changes through time are due to land‐cover variations. A series of spectral trajectories were then extracted to assess changes in land‐cover through time. Secondly, a land‐cover classification was produced from the baseline 1984 imagery and, using historic and future mine extents, the classification was analyzed to determine the proportion of each land‐cover type affected through development. Results of the analysis indicate that since 1984 there has been a larger reduction in mixedwood dense and broadleaf vegetation classes than mixedwood sparse or dense conifer stands in the area. Based on the delineations of mine‐site activity, the area of woodland and wetland habitat subject to development has increased from approximately 2,520 hectare (ha) in 1984 to 32,930 ha in 2005.     

Fragmentation regimes of Canada's forests

Canada is a large nation, approximately 1 billion hectares in size, and until recently, no national assessment of forest fragmentation had been undertaken. To assess national level biodiversity and ecosystem condition, national drivers of forest fragmentation are identified as being either primarily natural (e.g., resulting from wildfires, water features, or topography), or primarily anthropogenic (e.g., resulting from urbanization or roads and associated activities such as forest harvesting and oil and gas exploration). The relative importance of each of these fragmentation drivers within Canada's ten forested ecozones, which occupy approximately 650 million ha, is assessed using ecozone summaries and standard scores. Forest pattern metrics were generated from a Landsat‐derived land cover product and fragmentation drivers were characterized using available national datasets. Through this analysis, we combine and portray the relative importance of forest patches with spatial layers indicative of natural and anthropogenically induced conditions as driving various fragmentation regimes over the forested area of Canada. The forest fragmentation in Canada can be characterized primarily by natural drivers, whereas fragmentation regimes attributable to anthropogenic drivers are typically regionally located and related to industrial activities and access (i.e., roads). We identify three scenarios in our results that characterize forest fragmentation in Canada: ecozones with similar forest patterns but different drivers; ecozones with similar patterns and drivers; and finally, ecozones with both different patterns and different drivers. Our findings indicate that national assessments of forest fragmentation should account for both natural (and inherent) and anthropogenic sources of fragmentation.     

基于GIS的盐城城市内部空间结构演变分析

根据1984、1997、2003、2006年4个时相数据,运用GIS的空间分析方法,对盐城城市工业、居住、公共服务用地的空间分异特征进行分析,并利用多种景观格局指数,分析了三种功能用地的完整性、集聚性和异质性特征。结果表明:1984-2006年盐城城市内部空间结构演变过程可划分为集聚、分散、再集聚三个阶段,同时演变中存在"工业围城"、城市中心区的工业和居住用地比重偏大等问题。     

Spatial pattern of land cover changes across Northeast China over the past 300 years

To accurately model the regional climatic effects of land use/cover change processes, precise reconstructions of historical land cover are essential. Over the past 300 years, the northeastern region has undergone more significant land cover change than any other region in China owing to large numbers of farmer migrants from North China, reflecting the tremendous effects human activities can have on such changes. In this paper, based on official statistical data, documentary records, survey data, and modern remote-sensing data and vegetation and soil maps, land cover changes across Northeast China over the past 300 years have been reconstructed through cropland data calibrations using correlation analysis, potential vegetation reconstructions, urban area estimations, spatial analyses of land cover type changes by K-mean clustering analysis, and consideration of land use driving forces. The results indicate that cropland expanded gradually from south to north through the cities of Shenyang, Jilin, and Ha’erbin as well as out to the margins of the central plain of Northeast China, with a maximum expansion occurring in the 1950s. Pristine forests and grasslands diminished significantly, especially in the early twentieth century, due to this expansion of cropland. The conclusions drawn from these results are, first, that these results provide a scientific understanding of the process by which the original land cover was replaced by cropland in Northeast China over the past 300 years. Second, the results enabled the development of a series of land use/cover changes maps with 50–100 year time resolutions and county-level spatial resolutions. Based on the reconstructed results of these land cover type changes, the dynamics and causes of land cover changes are discussed in their social–historical contexts.     

Contesting land,creating community,in the Highlands and Islands,Scotland

This paper draws on research in four communities in the Highlands and Islands, Scotland, to explore how the notion of community and community identity are re‐worked in the political spaces created as communities claim collective rights to land. In the cases of the Assynt Crofters’ Trust, the Bhaltos Community Trust, and Laid, this has concerned land under crofting tenure; in the case of the claim of the North Sutherland Community Forestry Trust, the land on which the Naver Forests stand is the responsibility of the Scottish Ministers and is managed by Forest Enterprise. The four case studies differ with respect to membership and institutional practices and thus provide fertile ground on which to examine, comparatively, collective struggles for the land and the search for sustainable futures.     

The Role of Fire Disturbance on Runoff and Erosion Processes – a Long‐Term Approach,Mt. Carmel Case Study,Israel

The Mediterranean ecosystem of Mt. Carmel, Israel, is subjected to an increasing number of forest fires of various extents and severities. The impacts of forest fires on runoff and erosion are widely documented and include increased peak flows and soil loss until the return of a vegetation cover. Most studies, however, treat fire as a single event, whereas the present study is aimed at exploring the long‐term effects of repeated forest fires on eco‐geomorphic processes. The study integrates the results of plot‐based, detailed analysis of post‐fire runoff and erosion with vegetation recovery analysis, at a temporal‐spatial scale which includes the effect of reburning. Our results indicate that forest fires lead to a significant increase in runoff and sediment yields, particularly during the first two years following the disturbance, up to five orders of magnitude higher than from the adjacent unburnt control plots.     

历史上祁连山区森林的破坏与变迁考

祁连山区宜林面积为2000余万亩,但现有林地面积仅700多万亩（食蔬林、灌木林面积）,森林覆盖率不足15％,其减少的原因盖在于历史上的乱砍滥伐人为破坏之故。本文考索有关文献资料,对历史时期祁连山区林草资源的破坏状况作了系统探讨,以期为今天本区林草植被的保护和河西绿洲的可持续发展提供历史惜鉴。     

Integrating Multi‐Sensor Remote Sensing Data for Land Use/Cover Mapping in a Tropical Mountainous Area in Northern Thailand

Accurate mapping of land use/cover conditions provides essential information for managing natural resources and is critical for further examination of land use/cover change and its subsequent impacts on the environment. Remote sensing offers a means of acquiring land use/cover data in a timely manner, with optical remote sensing images commonly being used in land use/cover related studies. The persistent cloud cover during the rainy season in Southeast Asia, however, presents a challenge for using optical images in land use/cover mapping. Integrating multi‐sensor images of different spectral domains is thus desirable because more information can be extracted to improve the mapping accuracy. The purpose of this study is to assess the potential of using multi‐sensor data sets for land use/cover mapping in a tropical mountainous area in northern Thailand. Optical data from Landsat Thematic Mapper, radar images from Advanced Land Observing Satellite/Phased Array type L‐band Synthetic Aperture Radar (PALSAR), and topographical data were used, providing complementary information on land use/cover. Classification and accuracy assessment were conducted for 12 different combinations of the data sets. The results suggested that short crop mapping using multi‐temporal Phased Array type L‐band Synthetic Aperture Radar images offered insights into the distributions of crop and paddy fields. Because of the mountainous environment of the study area, combining topographic data of elevation and slope into the classification greatly reduced the confusion between different land use/cover types. Improvement of classification accuracy was evident especially in separating evergreen and deciduous forests from other vegetation types and discriminating urban village and the fallow field classes.     

大连市建成区土地利用时空演变与动力机制分析

借助ENVI和GIS技术对大连市1990年以来遥感影像资料及空间数据进行统计分析,研究其建成区扩张的时空演变及动力机制。研究结果表明,近20年来,大连市区建设用地扩张1.34倍,以东北为主要拓展方向。1990-1995年扩张速度和扩张贡献率最大,城市空间不规则扩张;1995-2005年城市以填充式发展为主,边界逐渐规则;2005年以来进入了新一轮的建设用地扩张时期。人口增长和经济发展对建设用地扩张的驱动作用趋于弱化,政府决策行为成为主要影响因素,尤其是金州区与新城区(开发区)的建立与发展对大连市区建设用地扩张有明显的牵引和带动作用。     

From Simplicity to Complexity: The Changing Geography of Land Vulnerability to Degradation in Italy

Although territorial disparities in land quality are commonly observed in Mediterranean‐type ecosystems, how different geographical gradients impact the changing distribution of land vulnerable to degradation over time and space is poorly investigated in southern Europe. The present study assesses the spatial distribution of vulnerable land according to a composite index that describes the degree of land vulnerability to degradation in Italy along eight gradients during two time periods (1960–1990 and 1990–2010), representing distinct socio‐economic and environmental conditions. While the degree of land vulnerability increased at similar paces from 1960 to 1990 and from 1990 to 2010, the spatial distribution of vulnerable land changed considerably. From 1960 to 1990, the area of vulnerable lands increased in coastal areas, lowlands, and areas with moderately high population density, mainly owing to the increased climate aridity. By contrast, peri‐urban areas experienced, especially in northern Italy, the highest vulnerability from 1990 to 2010 owing to increased human pressure on land generating, e.g. land‐use changes. Results indicate that the importance of the gradients shaping the distribution of vulnerable land in Italy is reflected in the (changing) role of climate, vegetation cover, and human pressure as factors predisposing land to degradation. Finally, policy implications of the changing geography of vulnerable land in the Mediterranean region are discussed.     

长株潭城市群都市区各类城市建设用地的时空变化研究

以长株潭城市群的都市区为研究对象,通过收集1990-2019年中7个年份的8类城市建设用地的空间分布数据,建立空间数据库,并依托各类城市建设用地的增量、对城市群及其片区的贡献率、在城市群中的扩张程度分布的测算,归纳各类城市建设用地时空变化的特征与规律.结果表明:1990-2019年,长株潭城市群都市区的城市建设用地扩张...     

‘Land of Fires’: Urban Growth,Economic Crisis,and Forest Fires in Attica,Greece

This study investigates the spatial distribution and basic characteristics of 2692 forest fires between 2000 and 2011 in Attica, Greece, a rapidly expanding urban region. Fire variables were assessed, together with variables describing the socio‐economic local context in three distinct periods of Athens’ expansion (2000–2003: semi‐compact expansion and economic growth before the 2004 Olympic Games; 2004–2007: infrastructure development and discontinuous expansion following the Olympic Games; 2008–2011: crisis‐driven decline of the construction industry). Fire characteristics changed over the three periods following the negative trends in the construction industry. Burnt areas decreased in the rural area around Athens and the opposite pattern was observed in the peri‐urban belt. Our findings suggest that the temporal and spatial distribution of forest fires in Attica reflects the construction boom stimulated by the 2004 Olympic Games and the subsequent economic crisis.     

WHOSE WOODS ARE THESE? COUNTER-MAPPING FOREST TERRITORIES IN KALIMANTAN,INDONESIA

This paper examines the politics of land and forest rights in Kalimantan (Indonesian Borneo). Forest mapping by government forestry planners allocates rights of resource use and land access according to forest types and economic objectives, only rarely recognizing indigenous occupancy rights or forest territories customarily claimed or managed by local people. As maps and official plans based on them ignore, and in some cases criminalize, traditional rights to forest, forest products, and forest land for temporary conversion to swidden agriculture, indigenous activists are using sketch maps to re-claim territories - a process that requires re-defining many traditional forest rights. The paper considers the political implications of mapping and the implications of a focus on land use rather than forest use.     

基于遥感信息的绿洲城镇群空间发展研究——以乌鲁木齐都市圈为例

以乌鲁木齐都市圈为研究区域,在分析遥感信息的基础上,探讨干旱区绿洲城镇群的空间发展过程与未来的空间发展模式。首先,对1989年的TM和2002年的ETM+影像进行解译,提取研究区的主要用地信息。然后,基于解译信息分析农业用地、城镇用地与农村居民点的变化情况,揭示绿洲城镇群的动态演化过程。再次,探讨了研究区发展过程中出现的行政界限束缚城镇发展、城镇间无序化的分散发展以及绿洲基底景观的破脆性增强等空间问题。最后,在分析动态变化的基础上,针对现有的空间发展问题,提出了一些空间发展构想,以期对本区今后空间的合理发展提供借鉴。     

Interdisciplinary Research into the Legacy of the Medieval Metropolis of Soba in a Modern Khartoum Suburb

Recent research at Soba focuses on the tangible and intangible heritage of the medieval capital of Alwa kingdom, whose remains cover approximately 275 ha. About 222 ha of this area has been built up or transformed into agricultural land in the past 30 years. An ethnographic survey was also carried out in the built-up area to understand how the residents engage with the archaeological heritage and material remains. The undeveloped area of the capital (53 ha) was the focus of interdisciplinary archaeological fieldwork conducted in 2019 and 2020. A large-scale geophysical survey, using a fluxgate gradiometer and ground-penetrating radar, was initiated in the undeveloped area, and excavation trenches were opened to verify distinctive magnetic anomalies. Along with the ethnographic and geophysical data, the study of the pottery, burials, and stratigraphic sequence (supplemented with radiocarbon dates) provides new insights into the spatial organization of the medieval capital.

     

Transforming the Classic Political Forest: Contentious Territories in Java

Java’s extensive political forests and their contentious social relations have been profoundly transformed since the turn of the 21^st century. This paper analyses new forms of forest land use, control, and revenue distribution, shaping and shaped by political-economic changes and neoliberal-era reforms. Villagers’ expanded uses, access to, and control of the forest understory under the violently thinned out canopies of the main tree species has generated newly spatialised forest politics, with new institutions and forest labour practices. The changes in land, species, and labour controls, and in villagers’ access to forest products and revenues define this historical transformation in the constitution of Java’s classic political forest. Contentious co-production has resulted in fragmented territories and a momentary (at least) weakening of state controls within the old imperial political forest.     

行政边界区域土地利用与空间发展模式研究——以长株潭结合部为例

以长株潭结合部暮云镇为例,主要采用2004与2010年土地利用数据,从动态变化与多维综合视角,对行政边界区域土地利用与空间发展的特征、机制及问题进行系统分析,在此基础上归纳理论模式。研究表明:①暮云镇土地利用结构由农村型向城镇型快速转变,城镇用地比重年均约增加2个百分点,其中居住、教育科研、交通和工业等用地增加显著;②受主体功能定位、过境通道建设、周边城市辐射差异和规划管理制度变迁等因素影响,暮云镇空间格局与扩张模式快速演变,芙蓉大道沿线新增城镇用地占全镇82.78%,北、中、南区域开发强度分别上升20.95%、7.96%和1.58%,城镇用地平均图斑面积增长2.04倍。③研究区土地利用与空间发展存在诸多阶段性和结构性问题,应加强综合路网建设、公共设施用地供给、建设用地优化布局与集约利用以及生态环境保护。     

Integrating Landsat and Land Systems for Cover Maps in Southern Inland Queensland

Digital analysis of Landsat data is applied to up-dating land cover maps for the Goondiwindi district of southern, inland Queensland. The imagery was paired with climax cover maps obtained from land systems reports with analysis conducted separately for each of three climax cover types (open forest, woodland and open woodland). Computer classification using this approach produced readily interpreted and reliable results. This work demonstrates that Landsat can be used in conjunction with existing, land systems derived maps to produce data that combine the advantages of two approaches to environmental survey, the former being based on current land cover/land use and the latter on the original environment and its land use potential.     

江南丘陵区农村居民点空间演变特征及影响因素研究——以长沙市为例

以江南丘陵区的长沙市为例,以1989年和2013年的Landsat TM影像及DEM为数据,应用GIS空间分析方法,对长沙市1989-2013年农村居民点空间演变的过程、格局、特征及影响因素进行研究。结果表明:①农村居民点密度不断加大,居民点空间扩展特征显著,但居民点布局较为分散;②农村居民点用地布局低地指向性特征明显,不同地貌类型区的农村居民点地域分异特征较为显著;③农村居民点空间布局的道路和河流指向性特征明显,距离道路与河流越近,农村居民点面积越大,反之则越少;④自然环境决定了长沙市农村居民点总体空间布局,同时,经济发展、农村城镇化与工业化、交通条件、政策制度等因素对农村居民点空间演变具有重要的影响。     

Assessment of Riparian Rainforest Vegetation Change in Tropical North Queensland for Management and Restoration Purposes

Changes in riparian vegetation extent in northern Queensland, Australia were assessed using aerial photographs from 1944 and 2000. Change in riparian extent was recorded as vegetation gain or loss. Changes in density were recorded as vegetation thickening. Riparian forest coverage increased by 22 ha during this time period in the Mossman River catchment. A total of 124 ha of riparian forest were gained, while 101 ha of riparian forest were lost. A further 59 ha of forest increased in density over this time period. Clearing, changes in farm management practices and natural stream channel movement have been identified as three potential causes for these changes. Areas with little or no riparian vegetation were identified and categorised into priority levels for potential revegetation efforts.