共查询到20条相似文献，搜索用时 31 毫秒
1.
Giovana M. de Espindola Ana Paula D. de AguiarEdzer Pebesma Gilberto CâmaraLeila Fonseca 《Applied geography (Sevenoaks, England)》2012,32(2):240-252
The potential impact of deforestation in the Brazilian Amazon on greenhouse gas emissions to the atmosphere calls for policies that take account of changes in forest cover. Although much research has focused on the location and effects of deforestation, little is known about the distribution and reasons for the agricultural uses that replace forest cover. We used Landsat TM-based deforestation and agricultural census data to generate maps of the distribution and proportion of four major agricultural land uses throughout the Brazilian Amazon in 1997 and 2007. We built linear and spatial regression models to assess the determinant factors of deforestation and those major agricultural land uses - pasture, temporary agriculture and permanent agriculture - for the states of Pará, Rondônia, and Mato Grosso. The data include 30 determinant factors that were grouped into two years (1996 and 2006) and in four categories: accessibility to markets, public policies, agrarian structure, and environment. We found an overall expansion of the total agricultural area between 1997 and 2007, and notable differences between the states of Pará, Rondônia, and Mato Grosso in land use changes during this period. Regression models for deforestation and pasture indicated that determinant factors such as distance to roads were more influential in 1997 than in 2007. The number of settled families played an important role in the deforestation and pasture, the effect was stronger in 2007 than 1997. Indigenous lands were significant in preventing deforestation in high-pressure areas in 2007. For temporary and permanent agricultures, our results show that in 1997 the effect of small farms was stronger than in 2007. The mapped land use time series and the models explain empirically the effects of land use changes across the region over one decade. 相似文献
2.
Anette Reenberg Peter Oksen Jannick Svendsen 《Geografisk tidskrift / udgivet af Bestyrelsen for Det Kongelige danske geografiske selskab》2013,113(2):57-69
The paper deals with land use changes in semi arid Burkina Faso, specifically the issue of field encroachment on extensively used land. Some theoretical perspectives of field expansions in agricultural production systems characterised by crop-livestock interaction are discussed with reference to Boserup's theories on intensification. The empirical part provides documentation for the land use patterns and practices, based on aerial photos from 1978 and 1994 and village surveys. Answers are sought to some of the key questions presented by the ‘land use land cover change community’, i.e.: how has ‘land cover been changed by human land use?’—how do immediate human and biophysical dynamics affect the sustainability of specific types of land uses?—and how do land uses and land covers affect the vulnerability of land users in the face of change? Based on the findings, the paper proposes the notion of the expansion dilemma which questions the theory that agricultural expansion should always be perceived as a forerunner of intensification. 相似文献
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Chuyuan Wang 《社会与自然资源》2014,27(7):742-758
Direct action land reform (DALR) and settlement formation are new drivers of deforestation in the Brazilian Amazon. However, until now no research has paid attention to fragmentation patterns and the social processes that lead to them. This article analyzes two types of settlements, spontaneous and social movement organization-led settlements. The study uses neutral landscape models (NLMs) to compare simulated landscapes with the real fragmentation patterns found in DALR settlements. In sequence, the article uses landscape metrics to analyze the temporal and spatial dynamics of fragmentation patterns in these two types of DALR settlements. Results showed that there are significant differences between real landscape patterns and simulated landscapes using NLMs. In other words, human interferences did play a significant role in shaping deforestation patches in DALR settlements. Our metric results revealed a process in which deforestation patch mean area, shape complexity, and physical connectedness increase over time. 相似文献
4.
The aim of this study is to bring a unique overview of past, current and plausible future land use development in Slovakia. The study assessed land change processes and their spatial determinants related to the most significant socio-political periods that have shaped the former socialist country over the past 30 years, namely, socialism (1980–1990), postsocialism (1990–2000), EU accession (2000–2006), EU membership (2006–2012). Using boosted regression trees, the impact of different biophysical, socioeconomic, policy and distance-based factors was evaluated on land transitions, categorised as urbanisation, agricultural intensification and extensification, afforestation, deforestation and forest disturbance (natural and management-induced). Results show significant shifts in the landscape management associated with the institutional changes, especially in the postsocialist period.Agricultural intensification, which dominated the socialist period, was in subsequent periods substituted by afforestation and agricultural extensification. High relative annual rates of forest disturbance have dominated land-use change over the past 30 years, while deforestation was a minor land-use change during the late socialist period. Urbanisation has played a significant role and changed considerably through the studied periods: high urbanisation rates under socialism, a massive decline in the postsocialism and EU accession periods and increasingly high urbanisation rates during the EU membership period.Taking into account national and international (EU related) demands, we assessed land use development for 2040 within five different future land use scenarios. These scenarios were characterised as either extensions of current development trends, or as developments along axes that target globalisation or regionalisation, and more or less intervention. Results show that afforestation is by far the land-change process that will have the greatest impact on future Slovakian landscapes, mostly in rural areas. Among changes in agriculture, all scenarios uniformly suggest that extensification will exceed intensification mostly at the cost of arable land. In addition, urban areas will expand at the expense of arable land, particularly in the accessible city hinterlands. 相似文献
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土地利用集约化研究的回顾与未来工作重点 总被引：7，自引：1，他引：6
土地利用集约化是粮食安全、经济发展与生态保护等多重压力作用下人类土地利用的必然选择。积极推进土地利用集约化进程,使其向可持续集约化方向发展,对于中国这样人多地少的国家而言,具有尤为重要的意义。土地利用集约化研究兴起于20世纪60年代,但源流更远的农业生产潜力研究、农业生产要素配置研究等与土地集约利用有关的研究成果,同样加深了人们对土地利用集约化规律的认识。由于这些工作分散于多个学科领域,相关成果并未得到很好梳理。为了弥补这一不足,本文重点围绕基本特征与测度指标、极值问题与潜力研究、驱动因素与限制因素、环境影响与可持续集约化等4个方面,简要回顾了至今为止土地利用集约化方面的主要研究成果,并概要介绍了监测和制图、路径选择、政策选择、城镇用地“集约化”等有待进一步探讨的主要问题。 相似文献
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土地利用变化的动力因子和动力机制是土地科学研究的核心问题。这一问题近30年来得到前所未有的关注,相关研究成果不断涌现,但是这些成果主要关注自然因子和社会经济因子等外在因素,却没有充分重视土地利用变化中蕴含的内在目标和由此派生的内在动力,客观上导致土地利用变化动力机制研究一直难以深入。本文以新疆地区为案例区,以土地、资本和劳动等生产要素生产效率变化为切入点,利用趋势拟合方法,分析了区域土地利用变化过程中要素产出效率的变动规律。结果显示,无论是近10年还是近30年区域棉花生产中,以及近30年区域粮食生产中,只有劳动生产率呈长期增长趋势。这一结果意味着人们对劳动生产率的追求可能是土地利用变化的内在动力。据此,进一步讨论了人们追求劳动生产率增长的原因及其与追求利润最大化等目标的关系,提出了"土地利用变化是人们在变化环境下不断追求劳动生产率增长的结果"这样一个观点。 相似文献
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基于遥感的呼伦贝尔盟农牧业土地利用变化及其对地区农业持续发展影响的研究 总被引：31，自引：1，他引：30
随着人口的增长, 人类活动对土地利用/土地覆盖变化的影响越来越大, “人口-资源-环境”问题越来越突出,因此,土地利用/土地覆盖变化的研究尤为重要。本文利用1986年和1996 年两期陆地卫星TM 数据, 分析探讨了呼伦贝尔盟近十年来农牧业土地利用数量变化及其区域差异,并通过计算耕地重心,分析了近十年来呼伦贝尔盟耕地的空间变化规律, 在此基础上进一步探讨了呼伦贝尔盟农牧业土地利用变化对地区农业持续发展的影响。结果表明： 十年来, 呼伦贝尔盟农牧业土地利用变化很大, 耕地面积大幅度增加,草地与未利用地面积减少;农牧业土地利用变化空间差异非常明显,导致十年来呼伦贝尔盟耕地重心向西北方向移动33.15 km , 耕地生态环境发生了显着变化; 呼伦贝尔盟耕地面积大幅度增加, 对合理开发利用耕地资源, 促进地区农业持续发展起到了积极的作用。 相似文献
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Armed-conflicts often occur in tropical areas considered to be of high ‘conservation-value’, termed as such for their biodiversity or carbon-storage functions. Despite this important overlap, few studies have assessed how forest-biomass is affected by armed-conflicts. Thus, in this paper we develop a multinomial logit model to examine how outcomes of the interactions between carbon-storage, armed-conflict and deforestation rates are linked to social, institutional and economic factors. We use Colombia as a case study because of its protracted armed-conflict, high forest-cover, sustained deforestation rates and on-going peace processes. Our empirical results show that the impacts of armed-conflicts on forest-cover are connected to specific socio-economical processes, such as unequal land distribution and land-grabbing, which typically occurs as part of ‘agricultural colonization’. Findings address a research gap by providing statistically sound evidence for associations between armed-conflicts and land-related grievances, which has rarely been demonstrated empirically. Our results also suggest that forest commons are associated with reduced armed-conflict, and simultaneously provide contributions to carbon storage and to meeting basic needs. Moreover, our forest-conflict transition models provide useful visual means to capture and relay to policymakers-the causes of forest cover-changes in a conflict-affected country. Finally, our findings imply that in dedicating their efforts to resolving land-ownership disputes, the Colombian government might uphold their international climate change commitments via reducing deforestation and hence forest based carbon emissions, while pursuing their national security objective via undermining opportunities for guerrilla groups to operate. 相似文献
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Underlying motivation for land use change: A case study on the variation of agricultural factor productivity in Xinjiang, China 总被引：1，自引：0，他引：1
Huiyi Zhu 《地理学报(英文版)》2013,23(6):1041-1051
Understanding the driving forces and mechanism of land use change is a key issue in land change science, and has received much attention over the past 30 years. While many driving forces have been identified, the mechanism of land use change is still unclear, mainly because of limited knowledge of the underlying motivation for land use change. Traditionally, the underlying motivation for land use change was ascribed to people＇s pursuit of satisfying their own demands or that of profit maximization. However, those theoretical hypotheses combine all productive factors without highlighting certain predominant factor, in this paper, a case study was conducted on the variation of land productivity, capital productivity and labor productivity in agricultural land use in Xinjiang Uygur Autonomous Region of China. The case study revealed that only labor productivity presented a long-term increasing trend in regional cotton and grain production. This result implies that people＇s pursuit of increasing labor pro- ductivity is probably the underlying motivation for land use change. Additional details identi- fied in agricultural and non-agricultural land use in China support the above implication. As labor productivity is a determinant of people＇s living standards, increasing labor productivity means improving people＇s living standards. Therefore, it is concluded that land use change results from people＇s pursuit of increasing labor productivity in a changing environment. 相似文献
10.
This paper provides the first analysis at the sub-municipality scale of the relationships between population densities and deforestation in the Brazilian Amazon between 2000 and 2010. We use the database on deforestation published by the Brazilian space research center (INPE) and the population census data released by the federal geographical and statistical agency IBGE at their finest scale: the census tract level. By crossing the population density and deforestation variables, we identify ten human settlement patterns in the Amazon. There are low-low and high-high classes of population density and deforestation, but also low-high and high-low classes. This analysis helps understand the low overall relations in the Amazon for population and deforestation. We emphasize the expansion of large-scale agriculture and cattle ranching as causing the depopulation of rural areas while in many regions of the Amazon quite strong population densities coexist with relatively low extents of deforestation. Such findings stress the need to implement case-specific public policies in these regions in order to encourage human presence compatible with the conservation of forest cover and biodiversity. We also confirm the importance of the Amazon urbanization process, including the ‘discrete urbanization’ of rural areas, and the need to better recognize the distinct social and environmental problems of urban areas. 相似文献
11.
Sanzidur Rahman 《Singapore journal of tropical geography》2010,31(2):254-269
This paper provides a detailed analysis of agricultural land use change in Bangladesh over a 59‐year period (1948–2006) and examines how these have impacted crop diversity, productivity, food availability and the environment. The key findings of the analysis are: first, land use intensity has increased significantly over this period, mainly from the widespread adoption of a rice‐based Green Revolution technology package beginning in the early 1960s; second, contrary to expectation, crop diversity too has increased; third, although land productivity has increased significantly, declines in the productivity of fertilizers and pesticides raise doubts over sustaining agricultural growth; fourth, food availability has improved, with a reversal in the dietary energy imbalance in recent years despite a high population growth rate; and finally, the production environment has suffered with widespread soil nutrient depletion experienced in many agroecological regions. The policy implication points towards crop diversification as a desired strategy for agricultural growth to improve resource economy, productivity and efficiency in farming in Bangladesh. 相似文献
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LUCC研究的最新进展评述 总被引：150，自引：15，他引：135
土地利用/土地覆被变化(LUCC)是全球环境变化的重要组成部分和主要原因之一,进入新世纪以来,LUCC研究一直是地理学研究的前沿与热点。本文综述了2002年8月在南非德班国际地理学联合会(IGU)"2002年区域地理大会"上有关LUCC的主要研究成果,认为国际上LUCC研究在应用RS、GIS技术开展土地利用/土地覆被变化监测、评价与制图;农村与农业土地利用/土地覆被变化分析;城市土地利用/土地覆被变化分析;土地利用/土地覆被变化动力学;土地利用/土地覆被变化与生态环境等五个方面取得最新进展,反映出LUCC研究范围在进一步拓展,研究内容在进一步深化。 相似文献
13.
The objective of this study was to better understand the linkages between spatial patterns of forest use, land use, and rates of deforestation. We focused on a region of the Brazilian Amazon characterized by a variety of spatial patterns of deforestation and that experienced rapid deforestation in the last decade: the colonization project “Pedro Peixoto” in the extreme East of Acre State. By combining time series of remote sensing data and household survey data, we tested the hypothesis that each spatial pattern of deforestation is associated with specific socio-economic characteristics of land managers. The statistical results support our hypothesis. However, spatial patterns of deforestation are not a consequence of the main economic activities. Rather, spatial patterns of forest use are linked to the pre-conceived design of the settlement project. The main economic activities are influenced by factors such as the property size, their location and disposition, and the availability of infrastructure. 相似文献
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Continuity and change: Spatiotemporal land use dynamics on Bellona Island, Solomon Islands 总被引：2，自引：2，他引：0
Torben Birch-Thomsen Anette Reenberg Ole Mertz Bjarne Fog 《Singapore journal of tropical geography》2010,31(1):27-40
Traditional agricultural land use systems in the humid tropics of the Southwest Pacific are, as elsewhere, affected by globalization processes. This paper analyzes the directions of change in the land use system of Bellona, a small outer island in the Solomon Islands. We focus on the human–environmental interaction that shapes land use patterns and practices in the context of theoretical lines of thought concerning intensification of agricultural systems in the tropics. Aerial photography from 1966 and satellite imagery from 2006 in conjunction with studies from the 1960s and a contemporary household survey reveal only minor changes in the agricultural system. Land use and land cover dynamics are related to agricultural strategies, demographic factors, institutional actors as well as biophysical drivers or constraints. Local agricultural production still contributes significantly to local subsistence but imported food has also become a major food source. Hence, land use has become partially disconnected from the local population pressure and therefore remains relatively stable while the larger livelihood portfolio has undergone significant diversification. At present, the agricultural system is a supplement to a range of strategies supporting the increasing number of people on the island. This explains why land use patterns continue relatively unchanged while livelihood and food supply strategies have changed. 相似文献
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Received date: -- Revised date: -- Foundation item: Under the auspices of the National Natural Science Foundation of China 《地理学报(英文版)》2000,(3)
1 Introduction1.1 Introduction to Liaocheng PrefectureLiaocheng
Prefecture lies in northwest of Shandong Province and slightly north to the center of the Huang-Huai-Hai Plain with latitudes between 35(47'N and 37(02'N and longitudes between 115(16'E and 116(32'E. Administratively, it consists of two cities (Liaocheng and Linqing) and six counties (Yanggu, Shenxian, Chiping, Dong'e, Guanxian and Gaotang). It covers a total area of 8590 km2 with a maximum distance of 114 km from eas… 相似文献
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城乡土地市场一体化对土地利用/覆被变化的影响研究综述 总被引：6，自引：1，他引：5
为了破除城、乡土地市场分割现状,最终实现“山水林田湖”共同发展的目标,需要推进城乡土地市场一体化发展。分别从城市土地市场、农村集体性建设用地非正式市场和农村农用地流转市场3个方面对土地利用/覆被变化的影响机理研究进行梳理。结果认为：第一,城乡土地市场割裂的状况仍然存在,并且对土地利用/覆被变化产生较大影响;第二,城市国有建设用地市场的发育程度不同,直接影响土地供求关系和土地利用结构,甚至对土地利用配置效率产生影响;第三,农村集体性建设用地市场已现雏形,但由于产权的模糊性而缺乏法律上的监管和保障,加快了土地利用类型的过度非农化转化。另外,农用地流转市场的出现也改变了土地利用的功能和类型;最后,城乡土地市场分割现象会对土地利用系统的可持续性和生态环境产生一定影响。在以上研究结果基础上认为未来研究需要进一步加强对城乡土地市场一体化的分析,且揭示城乡土地市场一体化对区域土地利用/覆被变化影响机理（格局、过程、效应）。 相似文献
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随着全球变暖趋势的增强,土地利用变化是全球变化中的重要组成部分。土地利用变化研究尤其是空间变化研究就成为了研究者非常关心的问题。以云南省保山杨柳小流域土地利用变化的实例分析,详细阐述了GIS的空间分析方法及其在土地利用变化研究中的应用。利用转移矩阵研究结果显示:该小流域农地总变化量最大,其次是有林地和荒山,变化最小的是水体和未利用地,有林地和未成林造林地以交换变化为主,水体和居民地净变化为主;从新增的角度来说,农地转化为有林地最具有转换优势,其次是农地转换为荒山;从流失的去向看,牧地转换为农地最具转换优势,其次是农地转换为牧地。 相似文献
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The environmental effects of disease are broadly recognized but still not fully understood. The impact of health on economic development has been well-documented, as have how changes in land cover can contribute to poor health. However, little is known about how changes in health may impact land use and land cover. Fallowing has long been regarded as an advanced, sustainable land use decision employed by subsistence agriculturalists. In the presence of a prolonged illness, however, subsistence agriculturalists may also potentially use fallowing as a coping mechanism. In this paper we seek to understand the extent to which fallowing is used as a coping strategy by households facing a prolonged illness. If illness threatens a household's labor supply, it could affect their ability to cultivate all of their land and may impact food security and general economic well-being. Additionally, it may also impact the actual landscape, as previously agricultural land may revert to a transitional state or land abandonment. This study employs mixed methods to determine if unhealthy agricultural households use fallowing as a coping strategy, identifies whether or not unhealthy fallowing households are more vulnerable agriculturally and economically than their healthier fallowing counterparts, and examines whether there is a land cover effect that can be detected using Landsat TM/ETM + satellite imagery. 相似文献