Landscape Structure and Historical Processes Along Diked European Valleys: A Case Study of the Arc/Isère Confluence (Savoie, France)

/ The valleys of European piedmonts constitute changing narrow corridors within which water, matter, nutrients, energy, and species flow. The dispersion patterns of these flows have been significantly disturbed since the end of the 18th century. Thus, western European valleys have been changed into complex mosaics by implementation of socioeconomical programs. In order to define future actions allowing the preservation of this "ecocomplex" (Blandin and Lamotte 1988), it is necessary to gather precise information of the landscape dynamics. Hence, the study of the European river valleys must be based upon two major steps: (1)the analysis of the present landscape with suitable remote sensing techniques, allowing us to map the complex mosaic of narrow corridors; and (2) the analysis of temporal landscape development patterns since the first engineering works that have transformed the braided channel system. In this paper, the efficiency of the addition of two techniques is highlighted: (1) the "wavelet merging method" from multispectral and panchromatic SPOT images for the floodplain land-cover mapping, and (2) the historical reconstruction techniques from old maps and archive documents in order to analyze the cumulative impacts of engineering works on landscape diversity. To illustrate the method, a particularly complex case study is chosen: the Arc/Isere confluence (downstream from Albertville, Savoie, France). Remote sensing, field survey, and historical reconstruction allowed us to distinguish two types of spatial units: (1) the "functional sets" characterized by independent state factors (edaphic, hydrological, and topographic) and supporting a limited number of vegetation types (spontaneous or cultivated), and (2) the functional unit (= ecotope), which corresponds to a unique combination of vegetation type/functional set.KEY WORDS: Landscape ecology; Floodplains; Vegetation; Land use; Remote sensing; Historical reconstruction; Mapping; Merging methods; Human impacts; Alps; Isere river; France     

Implications of Land Use Changes on Carbon Dynamics and Sequestration—Evaluation from Forestry Datasets, India

Forests and soils are a major sink of carbon, and land use changes can affect the magnitude of above ground and below ground carbon stores and the net flux of carbon between the land and the atmosphere. Studies on methods for examining the future consequences of changes in patterns of land use change and carbon flux gains importance, as they provide different options for CO₂ mitigation strategies. In this study, a simulation approach combining Markov chain processes and carbon pools for forests and soils has been implemented to study the carbon flows over a period of time. Markov chains have been computed by converting the land use change and forestry data of India from 1997 to 1999 into a matrix of conditional probabilities reflecting the changes from one class at time t to another class time t+1. Results from Markov modeling suggested Indian forests as a potential sink for 0.94 Gt carbon, with an increase in dense forest area of about 75.93 Mha and decrease of about 3.4 Mha and 5.0 Mha in open and scrub forests, if similar land use changes that occurred during 1997–1999 would continue. The limiting probabilities suggested 34.27 percent as dense forest, 6.90 as open forest, 0.4 percent mangrove forest, 0.1 percent scrub and 58 percent as non-forest area. Although Indian forests are found to be a potential carbon sink, analysis of results from transition probabilities for different years till 2050 suggests that, the forests will continue to be a source of about 20.59 MtC to the atmosphere. The implications of these results in the context of increasing anthropogenic pressure on open and scrub forests and their contribution to carbon source from land use change and forestry sector are discussed. Some of the mitigation aspects to reduce greenhouse gas emissions from land use change and forestry sector in India are also reviewed in the study.     

Developmental Processes, Changing Lifestyle and Traditional Wisdom: Analyses from Western Himalaya

Traditional knowledge and practices are important in prudent resource use and biodiversity conservation. The implications of modernization and changing lifestyle are discussed in the context of agriculture and resource use, the two sectors in which maximum modernization has occurred. The information was gathered through observations and structured interviews over three years (July 1996 to July 1999) of field work in the western Himalaya. It was observed that forest based subsistence agriculture has given way to the market dependant cash crop cultivation. That apart from loss of genetic diversity, has also resulted in the degradation of forests. The use of wild plants in the day-to-day activities has also declined and dependence on high value market products has increased. Currently, wild plants are used only if no other cheap substitute is available in the market or if the use is economically beneficial to the people. Thus, the knowledge gathered through ages of experience is eroding because of the activities geared for short-term economic benefits which, in long run, may not be sustainable.     

INCREASED BASEFLOW IN IOWA OVER THE SECOND HALF OF THE 20TH CENTURY1

ABSTRACT: Historical trends in annual discharge characteristics were evaluated for 11 gauging stations located throughout Iowa. Discharge records from nine eight‐digit hydrologic unit code (HUC‐8) watersheds were examined for the period 1940 to 2000, whereas data for two larger river systems (Cedar and Des Moines Rivers) were examined for a longer period of record (1903 to 2000). In nearly all watersheds evaluated, annual base flow, annual minimum flow, and the annual base flow percentage significantly increased over time. Some rivers also exhibited increasing trends in total annual discharge, whereas only the Maquoketa River had significantly decreased annual maximum flows. Regression of stream discharge versus precipitation indicated that more precipitation is being routed into streams as base flow than as storm flow in the second half of the 20th Century. Reasons for the observed stream flow trends are hypothesized to include improved conservation practices, greater artificial drainage, increasing row crop production, and channel incision. Each of these reasons is consistent with the observed trends, and all are likely responsible to some degree in most watersheds.     

灾害旅游资源探讨

灾害经济学中的害利互变原理表明，灾害也有“利”的一面。它在给人类造成巨大损失的同时，也塑造了奇异独特的灾害旅游资源，其开发利用效用是其他旅游资源无法代替的。本文系统阐述了灾害旅游资源的基本属性、特性、类型及可持续开发利用的设想，以便使灾害旅游资源可以发挥更大的社会和经济效益。     

土地利用变化驱动下的上海市区水灾灾情模拟

对上海市区近50年来的土地利用结构变化进行了重建，并计算了由土地利用变化引起的上海市区水位变化量。以特定的1962年水灾为参照，模拟在同等雨强情况下，由土地利用结构变化和地面沉降引起的淹没范围的变化以及由此带来的水灾损失的变化。结果表明，在49mm／d降水条件下，由于土地利用的变化，使2001年的径流系数比1950年增大了34．0％，2001年的水位比1950年增高了45．9％；2001年的水灾灾情为1950年的1．0629倍；即使在目前千年一遇的防洪标准下，亦可造成相当于2001年地均GDP值0．088％(约为4．5亿元人民币)的损失，这是1991年相应数值的220倍。     

Maplnfo机助制图在土地利用总体规划中的应用

在土地利用总体规划中，传统的模拟制图日益暴露出其局限性。随着信息时代的到来，计算机机助制图以其强大的优势逐步取代了传统的模拟制图。阐述了在土地利用总体规划中应用Maplnfo机助制图的必要性和工作原理，并着重探索其在土地利用总体规划中的应用过程。     

Comparing Environmental Conditions Using Indicators of Pollution Hazard

/ Land use/land cover classifications for 1973 and 1991, derived from the interpretation of satellite imagery, are quantified on the basis of biophysical land units in a study area in southeastern Australia. Nutrient export potentials are estimated for each land unit based on their composition of land use/land cover classes. Spatial and temporal comparisons are made of the land units based on the calculated pollution hazard indicators to provide an insight into changes in the state of the environment and the regional significance of land use changes. For example, one ecosystem, unique to the study, showed a large increase in pollution hazard over the study period as a manifestation of an 11-fold rise in cleared area and an expansion of cropping activities. The benefits to environmental management in general are discussed.KEY WORDS: Land cover change; Nutrient export; Environmental condition; Pollution hazard; Agricultural pollution; Nonpoint source pollution; Diffuse pollution; Environmental degradation     

Reducing conflict over the Danube waters: equitable utilization and sustainable development

This paper develops the idea that the principle of equitable utilization must be applied in concert with sustainable water use not only in the resolution of specific disputes but in the cooperative management of water resources in general. It illustrates this point with two different cases involving the use of the Danube River. The first is the conflict over the Gabcikovo Nagymaros Dam, which now rests before the International Court of Justice. The author argues that a narrow legal ruling that fails to take into account broader issues of equitable utilization as they relate to sustainable development will not satisfactorily address the long-term questions at stake between the parties. The second involves the situation in the Danube Delta where the potential for conflict exists, but may be minimized through the convention and institutional framework developed to address the environmental degradation and pollution of the Danube River basin, which is based in part on the principle of equitable utilization and the goal of achieving more sustainable water use. The paper provides a brief overview of the geographical features of the Danube River and international water law. It then explores the principle of equitable utilization and sustainable water use in light of the two cases and discusses the implications for the resolution and management of conflicts involving internationally shared water courses.     

南滚河自然保护区的蕨类植物资源及其特点

本文记载了南滚河自然保护区蕨类植物２９科４７属５８种和它们的用途、分布区以及生境因子，并对其地理分布和生态特点进行了分析．