نتایج جستجو برای: total vegetation cover decreased by 362
تعداد نتایج: 7530927 فیلتر نتایج به سال:
This study assesses the ability of multitemporal Landsat Thematic Mapper (TM) data and the normalized diVerence vegetation index (NDVI) to spectrally separate grazed cool season and warm season grassland cover types in Douglas County, Kansas. Biophysical data collected during the summer of 1997 suggest that diVerences in the per cent of total living vegetation cover, per cent of senescent veget...
BACKGROUND The total amount of native vegetation is an important property of fragmented landscapes and is known to exert a strong influence on population and metapopulation dynamics. As the relationship between habitat loss and local patch and gap characteristics is strongly non-linear, theoretical models predict that immigration rates should decrease dramatically at low levels of remaining nat...
vegetation cover as the main factor affecting the water erosion plays an important role in preventingsoil loss. to this end, for better understanding the impact of vegetation cover on soil erosion andsediment yield over the major existing geological formations in the summer rangelands of balade inthe mazandaran province, rainfall simulation studies have been carried out using a portable rainfal...
land use may be regarded as one of the most important factors affecting theenvironment with respect to human activities. so far, destroying the rangelands andchanging them into the waste lands and poor rangelands has been proposed as the mostsignificant variations of land use done by human beings. this paper has been conducted toevaluate the variations of vegetation percentage and land uses in ...
This study assessed the effects of road-related alteration of substrate, including increased salinity, on vegetation along a meridional gradient in Fennoscandia. Vegetation community composition were surveyed in 29 randomly selected 1-m(2) sized roadside plots. Number of plant species and plant cover (%) on the plots were positively interrelated (p < 0.0001). Both variables also decreased towar...
Drylands cover 41% of the terrestrial surface and support > 36% of the world’s population. However, the magnitude of dryland degradation is unknown at regional and global spatial scales and at 15–30-yr temporal scales. Historical archives of > 30 yr of Landsat satellite imagery exist and allow local to global monitoring and assessment of a landscape’s natural resources in response to climatic e...
For an optimum use of natural resources in the sustainable development trend, there is a need to identify ecological resources in the shortest period of time and minimum possible cost. In this article, we aimed Management ecosystem by Assessment of plant covers changes at Taleghan Township in a twenty year period. Percentage of landscape and number of patch were among the metrics that were calc...
The preparation of vegetation cover maps by used the land inventory and a traditional method has a lot of cost and time. But today, remote sensing is one of the main sources of data collection and information production for study and monitoring land resources, and was efficient tools for providing quickly and timely data and information needs for program planning in the natural resource filed. ...
Estimating the extent of changes in forest and rangelands land cover, leads to a clear understanding of the growth or decline of these natural areas and planning for effective protection of these national assets. The aim of current study was to reveal the trend of land-use changes in the Dizmar protected area of Arasbaran vegetative area, using MSS sensor of Landsat-5 for 1984, ETM+ sensor of L...
Elevation gradients provide opportunities to explore environmental controls on forest structure and functioning. We used airborne imaging spectroscopy and lidar (light detection and ranging) to quantify changes in threedimensional forest structure and canopy functional traits in twenty 25 ha landscapes distributed along a 3300 m elevation gradient from lowland Amazonia to treeline in the Peruvi...
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