Brésil ; Dégradation de la végétation ; Forêt ; Image satellite ; Pará ; Pâturage ; Végétation
The analysis of the satellite imagery suggested that degradation of pastures were probably underestimated in the past because a considerable part of previous studies classified degrading pastures as secondary forests. Therefore, future climate
and carbon models should include a more exact analysis of tree-dominanted pastures to get a more detailed picture of reality. The paper deals with Bragantina, Capoeira, Juquira, pasture degradation, bush encroachment and satellite image classification. - (IfL)
An assessment of land degradation in the Northern Province from satellite remote sensing and community perception
Biomass ; Desertification ; LANDSAT ; MSS ; Perception ; Remote sensing ; Soil degradation ; Soil erosion ; South Africa ; Vegetation ; Vegetation index
Afrique du Sud ; Biomasse ; Dégradation des sols ; Désertification ; Erosion des sols ; Indice de végétation ; LANDSAT ; MSS ; Northern Transvaal ; Perception ; Télédétection ; Végétation
The assessment of land degradation in developing rural areas of South Africa is often hampered by a lack of reliable data. Remote sensing data offers a reliable source of information. In a case study in the Sekgosese district in northern South
Africa, the findings coincided with local community perceptions, although most people were unaware of the causes and effects of land degradation. - (AJC)
The AA. have simulated the spatial relationship between temperature change and long-term potential vegetation cover dynamics. The results show that the potential vegetation and birch forest range is highly sensitive to the temperature conditions
Grassland degradation in the Three-River Headwaters region, Qinghai Province
Biogeography ; China ; Grassland ; Qinghai ; Remote sensing ; Satellite imagery ; Spatial variation ; Vegetationdegradation ; Vegetation index ; Years 1970-79 ; Years 1990-99
Années 1970 ; Années 1990 ; Biogéographie ; Chine ; Date 2004 ; Dégradation de la végétation ; Formation herbacée ; Image satellite ; Indice de végétation ; Qinghai ; Télédétection ; Variation spatiale
In order to acquire objectively spatial-temporal processes of grassland degradation, MSS images in the mid and late 1970s, TM images in the early 1990s and TM/ETM images in 2004 were used. Grassland degradation in the Three-River Headwaters (TRH
) region was interpreted through analysis on RS images in 2 time series, then the spatial and temporal characteristics of grassland degradation in the TRH region were analyzed since the 1970s. Because grassland degradation had obviously regional differences
in the TRH region, it could be regionalized into 7 zones, and each zone had different characteristics in type, grade, scale and time process of grassland degradation.
Characterising vegetation cover in relation to land use in the Inkomati catchment, South Africa, using Landsat imagery
Environment ; Image analysis ; Mpumalanga ; Productivity ; South Africa ; Vegetation ; Vegetationdegradation ; Vegetation map ; Watershed
Afrique du Sud ; Analyse d'image ; Bassin-versant ; Carte de la végétation ; Dégradation de la végétation ; Environnement ; Mpumalanga ; Productivité ; Végétation
The paper assesses catchment-scale vegetation cover and condition, indicated by land degradation and vegetation vigour. Image classification into vegetation density categories is used in mapping land degradation. It can be mapped with certainty
Climat méditerranéen ; Dégradation de la végétation ; Dégradation des sols ; Erosion des sols ; Impact ; Incendie de forêt ; Israël ; Régénération ; Versant ; Végétation
Etablissement des vitesses de régénération de la végétation pour différentes étendues et sévérités de feux de forêts et pour différents aspects de versants.
The presence of a compact fragipan horizon help to explain the association of the degradation of the soil and the permeability of the substratum. This is possible on basis of the hypothesis which links the fragipan development to ice segregation
in permafrost aggrading in an environment with relatively high water supply from the subsoil. The degree of degradation, and its distribution in the landscape, can be explained in a much more satisfactory way by these processes associated with a periglacial
climate than by the presence of a particular forest vegetation.
Bois ; Cameroun ; Déboisement ; Dégradation de la végétation ; Forêt ; Forêt tropicale ; Modèle numérique ; Politique forestière
This paper addressed specific questions within the much broader discussion on policies to reduce tropical deforestation and degradation in developing countries. The short-to medium-run consequences of resource policies and trade liberalization
Defining degradation : the impacts of swidden on forests in Northern Thailand
Environment ; Environmental degradation ; Ethnic community ; Forest ; Land clearing ; Shifting cultivation ; Thailand ; Vegetation dynamics
Culture itinérante ; Dynamique de la végétation ; Défrichement ; Dégradation de l'environnement ; Environnement ; Ethnie ; Forêt ; Thaïlande
A reevaluation of the usual view that shifting cultivation leads to forest degradation, soil erosion, water shortages, and other undesirable changes. Author examines the swidden farming near three upland villages in northern Thailand. swiddens
An assessment of land degradation in the Save catchment of Zimbabwe
Environmental degradation ; Geographical information system ; Image analysis ; Land use ; Vegetation dynamics ; Watershed ; Zimbabwe
Analyse d'image ; Bassin-versant ; Dynamique de la végétation ; Dégradation de l'environnement ; Système d'information géographique ; Utilisation du sol ; Zimbabwe ; Zimbabwe de l'Est
Identification d'espaces susceptibles d'être dégradés. La télédétection et les techniques de SIG sont appliquées au district de Buhera. Données : images Landsat de 1992 et 2002, zonage agro-écologique, couverture végétale et densité de population
Land degradation assessment with the aid of geo-information techniques
China ; Duricrust ; Geographical information system ; Global Positioning System ; LANDSAT ; Remote sensing ; Shaanxi ; Soil degradation ; Soil erosion ; Thematic Mapper ; Vegetation index
Chine ; Dégradation des sols ; Encroûtement ; Erosion des sols ; GPS ; Indice de végétation ; LANDSAT ; Shaanxi ; Système d'information géographique ; Thematic Mapper ; Télédétection
This research integrated selected land degradation indicators (vegetation cover, proportion of drifting sand area, desertification rate, and population pressure) with geo-information techniques (remote sensing, geographic information system
and global positioning system) to assess the severity of land degradation risk. The northern part of Shaanxi province in China was taken as a case study. Satellite images of the study were acquired in October 1987 and in October 1999 (Landsat TM images). All
Logique spatiale de la répartition de la végétationdégradée par la pollution atmosphérique
Biological indicator ; Chemical pollution ; European part of Russia ; Pollution ; Saint Petersburg ; Spruce ; Tree ; Vegetation ; Vegetationdegradation
Etude de la dégradation de la végétation sous l'effet de la pollution de l'usine chimique de Tosno dans l'oblast de Leningrad. Le tableau 1 rassemble des données sur l'état de peuplements d'épicés commun (Picea abies), le tableau 2 sur la fréquence
Alaska ; Arctique ; Dégel ; Dégradation de l'environnement ; Impact ; Limite forêt-toundra ; Mollisol ; Palse ; Pergélisol ; Propriétés du sol ; Réchauffement climatique ; Thermokarst ; Végétation ; Zone froide
This study examines the relationship between vegetation and soil characteristics in an active thaw pond complex on Seward Peninsula in order to determine the mechanistic relationship between thermokarst formation and vegetation change at the forest
-tundra boundary. In particular, the AA. address 2 questions : what is the relationship between active-layer thickness, soil drainage, and vegetation? what are the temporal dynamics of tree colonization and mortality in this thaw-pond complex?
Channel geometry ; Experimentation ; Meander ; Mississippi ; Riparian vegetation ; Stream ; Stream flow ; United States of America ; Vegetation
The aim of this study was to induce the location of the maximum surface velocity or thalweg of a straight, degraded stream channel to meander through the use of managed emergent vegetation. This study showed that flow velocity can be markedly
reduced within and near the vegetation zones, flow can be diverted toward the opposite bank, and vegetation density can control the magnitude of these effects. The following discussion will focus on design considerations for stream restoration
In the Gavarras (NE Spain), a large number of plots on respective schists, leucogranite and granodiorite was studied for their soils and vegetation. Results are discussed, focusing on properties of humus forms and underlying mineral horizons which
are relevant for the susceptibility of these soils to erosion and degradation.
Action anthropique ; Dégradation de l'environnement ; Dégradation de la végétation ; Ecosystème ; Erosion des sols ; Montagne ; Northern Ireland ; Royaume-Uni ; Tourisme
Footpath degradation is assessed by comparison of surveys carried out in 1983 and 1992 along the principal cross mountain path: the Brandy Pad. Measurements show that overall path width has generally increased, as have the number of subsidiary