The impact of exurban development on forested areas in Kurgan City,Russia

Exurban communities—a significant form of urban sprawl—can transform natural land cover. Exurban development refers to an expansion of communities located outside a city and its suburbs. One of the main reasons these settlements develop is a desire by residents to live closer to nature and developers’ recognition of the profitability of addressing this desire. Additionally, exurbs can become prosperous regions settled by people with high income. However, exurban development not only directly affects community patterns, but also species patterns, habitat reduction and disconnection, as well as land cover and land use alterations. The purpose of this paper is a quantitative analysis of the land cover transformation and forest fragmentation in Post-Soviet Russia, based on an empirical case study of the city of Kurgan. This case study also contributes to the overall research of urban sprawl in Russian provinces by adding to the discussion of homeowners’ behavior, regional environmental policies, and their role concerning the impacts of exurban settlements on the natural environment. This paper uses remote sensing imagery, census data, and primary data to analyze land cover change due to the emergence of exurban communities around Kurgan, Russia, with specific emphasis on the changes to native vegetation resulting from human behavior and stakeholder preferences.     

基于Landsat8数据的沙湖叶绿素a反演研究

本文以武汉沙湖水体为研究对象,以“3S”技术为支撑,基于Landsat 8遥感影像数据与实测水质数据,根据各波段反射率的相关性,分析与研究了遥感影像数据的适宜波段,采用回归分析的方法,建立适合沙湖水体的叶绿素a浓度遥感反演模型。反演结果表明,以第4波段建立的多项式回归反演模型效果较好,其平均误差为7.28%,Landsat 8影像数据能有效用于沙湖叶绿素a浓度的监测,在空间分布上也呈现一定的空间格局形态,并显示沙湖西北角(新生路泵站)污染相对严重,与沙湖实际情况基本吻合,因此将Landsat 8影像数据应用于内陆湖泊水体叶绿素a浓度反演具有一定的可行性。     

长江中游城市群土地利用生态风险分析——以长株潭城市群为例

为揭示城市群发展对区域生态风险的影响,以位于长江经济带的长株潭城市群为研究区,利用1993-2013年Landsat遥感数据,定量获取土地利用变化特征,并基于移动窗口的景观生态风险指数,获得区域空间连续的生态风险指数等级分布图,分析长株潭城市群土地利用动态变化及生态风险时空变化特征。结果表明,近20年来,研究区土地利用变化较为显著,建设用地呈持续增加的趋势,耕地、林地面积在波动中减少且变化明显;近20年,生态风险等级面积变化显著,低风险区波动减少,中等风险区先减少后增加,较高风险区、高风险区均波动性增加。本研究为长株潭城市群土地资源可持续利用、生态风险的有效防范,以及对城市建设用地开发边界和生态红线的确定提供了参考,也为区域生态风险定量评价提供了有效的技术方法。     

基于Landsat8 TVDI的河套灌区旱情分析——以临河区为例

[目的]河套灌区是我国北方重要粮、油生产基地,该区域地处我国干旱区,及时有效地监测评价该地区的旱情状况,对农业有十分重要的意义。通过遥感手段监测河套灌区旱情状况,将研究区分为无旱、轻旱和干旱3个旱情等级,并对统计结果进行评价,以期为当地农业生产提供参考。[方法]选取2016年7月1日的两景Landsat8遥感影像数据,针对遥感参数进行计算反演,对归一化植被指数(NDVI)、地表温度(LST)和温度植被干旱指数(Temperature Vegetation Dryness Index,TVDI)等遥感参数分级统计,评价临河区旱情。[结果]3个旱情等级中,无旱的面积为466.38 km~2,占临河区面积的20.02%;轻旱的面积为1 176.50 km~2,占临河区面积的50.49%;干旱的面积为687.12 km~2,占临河区面积的29.49%。临河区东北地区旱情面积比重较大;西南地区靠近黄河及人工渠旱情面积较小或者无旱情发生。[结论]该方法适合农业旱情的快速监测评价,能较好地反映区域旱情空间分布,监测结果具有一定的实用价值。     

基于Landsat的黄河口地区土地利用类型研究

[目的]对黄河口地区的土地利用情况进行分类分析,为科学规划黄河口地区生态布局和进一步揭示人类与环境之间的发展关系及其相互影响提供理论依据。[方法]基于Landsat遥感数据利用3S技术对近20年来5景覆盖黄河口地区的卫星遥感数据进行解译分析,在科学制定分类标准基础上,结合目视解译和监督分类法提取研究区域内的土地利用类型,同时应用最小二乘法原理对各土地利用类型的变化趋势进行研究。[结果]近20年来,黄河口地区天然湿地和人工湿地的区域及面积均发生了不同程度的变化;黄河口地区滩涂湿地主要分布在东部区域和北部区域;受河流改道等影响,黄河口地区东部滩涂湿地区域和面积均发生过明显改变;黄河口地区各土地利用类型中耕地面积占比最大,滩涂湿地面积占比次之,盐碱地面积占比最小;耕地、城镇及建设用地、裸地和盐碱地面积多年来均呈增长趋势,其中城镇及建设用地面积呈逐年递增趋势,其他各类土地利用面积呈不规则递增趋势;湿地总面积呈减少趋势,其中除盐田及养殖池面积呈增长趋势外,其他湿地面积均呈减少趋势。[结论]黄河口地区受人类活动影响较大的各类土地利用面积变化率大,表明人类活动对土地利用面积变化的影响起主导作用。     

Twenty-three years of forest cover change in protected areas under different governance strategies: A case study from Ethiopia’s southern highlands

Tropical deforestation has heightened the need for effective governance of protected areas aimed at conserving natural resources, biodiversity, and ecosystem services. The southern highlands of Ethiopia hold some of the largest expanses of contiguous tropical forest in Ethiopia. This area also is undergoing rapid land conversion. Multiple protected areas with different management strategies and objectives have been established, in part, to conserve forests and the ecosystem services they provide. We examined four types of protected areas; a national park, a state-run forest enterprise, two occupied privately leased hunting concessions, and two unoccupied hunting concessions, to evaluate their effectiveness at protecting forest cover. We used 1509 field plots with medium-resolution Landsat imagery from 1987 to 2015 to develop models of forest cover at approximately five-year time intervals. We found protected areas that were actively managed for timber production or hunting were more effective at conserving forest cover than the national park and the unoccupied hunting concessions. Over the study period, net forest cover change was −7.8% for the national park, 12.9% for the state-run forest enterprise, −0.2% and 13.3% for the occupied hunting concessions and −14.0% and −13.0% for the unoccupied hunting concessions. We also discuss how the change in forest cover relates to historic political events. In places like Ethiopia where the federal resources needed to conserve forests are limited, promoting a network that includes both federally and non-federally managed protected areas can result in more area and forests under protection.     

基于植被指数的喀斯特流域赋水动态变化遥感监测研究——以贵州省为例

喀斯特流域具有特殊的双重含水介质,形成独特的地表—地下水系结构。因此,喀斯特流域水资源影响因素复杂多样,除气候、地貌、岩性等因素外,流域植被覆盖率也起到决定性的作用。本文在贵州省内选择20个流域作为研究样区,根据Landsat TM的植被光谱特征,流域赋水光谱特征,利用遥感技术,对TM影像进行光谱辐射亮度计算处理、表观反射率计算处理,并构建TVI、RDVI、EVI。根据现代数学分析方法的原理,借助Spss、MATLAB软件,探讨、建立喀斯特流域水资源监测、预测模型,并通过方差分析和样区检验,得出很好的预测效果。     

城市热环境空间格局及影响因素分析——以大连市金州区为例

近年来,城市化发展进程加快导致热环境发生变化,本文通过单窗算法反演地表温度、随机森林分类法对地物进行划分,结合GIS空间分析,对大连市金州区城市热环境的时空特征进行了研究。得出以下三点结论:(1)中心城区具有明显的热岛效应,地表温度总体上明显高于城市边缘区和郊区;(2)研究区包含5种主要地物类型,即植被、耕地、水体、裸土、建筑土地利用空间分布,其中耕地面积最大,水体面积最小;(3)在城市地表覆盖系统内,不同土地利用类型地表温度具有明显差异,其中建筑密集区、交通发达区与植被的LST最大温差可达10℃。     

Correlates of forest-cover change in European Russia, 1989–2012

European Russia rapidly transitioned after the collapse of the Soviet Union from state socialism to a market economy. How did this political and economic transformation interact with ecological conditions to determine forest loss and gain? We explore this question with a study of European Russia in the two decades following the collapse of the Soviet Union. We identify three sets of potential determinants of forest-cover change—supply-side (environmental), demand-side (economic), and political/administrative factors. Using new satellite data for three distinct types of forest-cover change—logging, forest fires, and forest gain—we quantify the relative importance of these variables in province-level regression models during periods of a) state collapse (1990s), and b) state growth (2000s). The three sets of covariates jointly explain considerable variation in the outcomes we examine, with size of forest bureaucracy, autonomous status of the region, and prevalence of evergreen forests emerging as robust predictors of forest-cover change. Overall, economic and administrative variables are significantly associated with rates of logging and reforestation, while environmental variables have high explanatory power for patterns of forest fire loss.     

Land-use and land-cover change in Lake Ziway watershed of the Ethiopian Central Rift Valley Region and its environmental impacts

Assessing land use and land cover (LULC) change in Lake Ziway watershed is important to evaluate the degradation of ecosystems and their environmental processes caused by the ongoing increase in human pressures. The present study analyzed the long-term LULC dynamics in the Lake Ziway watershed, which covers 7300 km² in the Ethiopian Central Rift Valley region. Three Landsat Satellite Image Series - Landsat MSS (1973), Landsat TM (1989) and Landsat Enhanced ETM+ (2018) - were the main input data from which three LULC maps were produced by employing Remote Sensing Techniques and Geographical Information Systems. The satellite data were supported by Google Earth and information gathered from informal discussions from local elderly people who are knowledgeable aboutthe area. The results over the last 45 years show that the major LULC changes in the study watershed have been the expansion of cultivated, agroforestry and settlement areas and the corresponding reduction in woodlands. Cultivation, agroforestry, and settlement LULC categories increased by 45%, 10.9%, and 141.4%, respectively. These changes are attributable to a combination of the ever increasing human population and the subsequent demands on environmental resources like agricultural lands, commercial and domestic fuelwood and charcoal. Other factors include poorly defined ownership arrangements and weak enforcement strategies on the existing land use policy. This has created open access mentalities among communities and intensified LULC changes in the watershed. Awareness raising and provision of technical training about conservation interventions should be provided to communities in the watershed.This study provides information for corrective measures to protect further degradation and irreversible losses that might happen to the biotic and abiotic resources in Lake Ziway watershed.