نتایج جستجو برای: technogenic desertification

تعداد نتایج: 2649  

2015
David A Seekell Vasilis Dakos

Regime shifts are abrupt transitions between alternate ecosystem states including desertification in arid regions due to drought or overgrazing. Regime shifts may be preceded by statistical anomalies such as increased autocorrelation, indicating declining resilience and warning of an impending shift. Tests for conditional heteroskedasticity, a type of clustered variance, have proven powerful le...

2011
R. C. Balling

Drylands throughout the world have always undergone periods of degradation due to naturally-occurring fluctuations in climate. However, over the past century, the human population in drylands has grown exponentially and the resulting pressures on the landscape have exacerbated various desertification processes, particularly in Africa. The degradation of drylands has led to changes in local, reg...

2013
Lihua Zhou Yanling Zhu Guojing Yang Yiqi Luo

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...

2010
A Gad A Shalaby

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...

2011
M. GUO Y. LIU X. F. WANG H. TANI

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...

2018
Zhenming Zhang Yunchao Zhou Shijie Wang Xianfei Huang

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...

2018
Qingfu Liu Yanyun Zhao Xuefeng Zhang Alexander Buyantuev Jianming Niu Xiaojiang Wang

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...

2008
Y. M. Yue K. L. Wang Z. C. Chen Y. Z. Yu

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...

Journal: :Remote Sensing 2017
Qiang Guo Bihong Fu Pilong Shi Thomas Cudahy Jing Zhang Huan Xu

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...

2004
M. B. Freidin I. A. Goncharova A. B. Karpov R. M. Takhauov

According to the most common definition a DNA-bank is a system of a genetic material storage. Applying to nuclear-chemical plant workers, DNA-bank creation is determined by the necessity to preserve a hereditary material of these people and their descendants for the further evaluation of consequences of technogenic factors action on human genome using a contemporary conceptual and applied advan...

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