نتایج جستجو برای: de desertification
تعداد نتایج: 1533589 فیلتر نتایج به سال:
In northern China, the recent eco-environment protective policies played a very important role in the ecological environment protection and rehabilitation. To better understand the quantitative effect of the prohibiting grazing policy on grassland desertification reversal process, in this paper, Yanchi County was selected as a case study to conduct a quantitative research on the effect of prohi...
Abstract Desertification is one of the fundamental problems that threaten many arid and semi-arid areas. The formulation of the United Nation Convention to Combat Desertification (UNCCD), adopted in Paris, 1994 and ratified in 1996, with the active participation of Egypt, gave emphasis on combating the major threats to sustainability of dry lands. Recently, different models were developed to fo...
Desertification is a serious threat to the sustainability of the environment and to human habitation. Kerqin sandy land is the largest sandy land in China, and is one of the most important origins of sandstorms in Northern China. Land desertification and frequent sandstorms in the spring strongly affect the growth of grassland vegetation and crops, and the effective of eco-environment in this r...
In this paper, the spatial distribution of stony desertification characteristics and its influencing factors in Karst areas in different sampling scales are studied using a grid sampling method based on geographic information system (GIS) technology and geo-statistics, with the rock bareness rate obtained through sampling with 150m × 150m grids in the Houzhai River Basin being taken as the orig...
Degradation of semi-arid and arid ecosystems due to desertification is arguably one of the main obstacles for sustainability in those regions. In recent decades, the Mu Us Desert in China has experienced such ecological degradation making quantification of spatial patterns of desertification in this area an important research topic. We analyzed desertification dynamics for seven periods from 19...
Karst rocky desertification is a special kind of land desertification developed under violent human impacts on the vulnerable ecogeo-environment in karst ecosystem. The process of karst rocky desertification results in simultaneous and complex variations of many interrelated soil, rock and vegetation biophysical parameters, rendering it difficult to develop simple and robust remote sensing mapp...
The Ordos Plateau, a typical semi-arid area in northern China, has experienced severe wind erosion events that have stripped the agriculturally important finer fraction of the topsoil and caused dust events that often impact the air quality in northern China and the surrounding regions. Both climate change and human activities have been considered key factors in the desertification process. Thi...
The worldwide phenomenon of shrub encroachment in grass-dominated dryland ecosystems is commonly associated with desertification. Studies of the purported desertification effects associated with shrub encroachment are often restricted to relatively few study areas, and document a narrow range of possible impacts upon biota and ecosystem processes. We conducted a study in degraded Mediterranean ...
Desertification is the reduction of ecologic and biologic on the earth surface, which might happen naturally or unnaturally (human). In this research, the TM and ETM images were used to study changes occurred in sand dunes during last 11 years and for determining the type of clay minerals. For evaluation of changes, maximum likelihood image classification and LMM, methods are carried out. Accor...
A common misunderstanding is that desertification is linked to the presence of deserts. The truth is that desertification can and does occur far from any climatic desert, as the presence or absence of a nearby desert has no direct relation to desertification. Desertification is the result of human induced land degradation which can be accelerated under severe drought conditions, and can occur u...
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