نتایج جستجو برای: vegetation degradation

تعداد نتایج: 196873  

2014
E. Symeonakis

It is widely accepted that land degradation and desertification (LDD) are serious global threats to humans and the environment. Around a third of savannahs in Africa are affected by LDD processes that may lead to substantial declines in ecosystem functioning and services. Indirectly, LDD can be monitored using relevant indicators. The encroachment of woody plants into grasslands, and the subseq...

2016
Yunlin Zhang Xiaohan Liu Boqiang Qin Kun Shi Jianming Deng Yongqiang Zhou

Terrestrial and aquatic ecosystem degradation is widely recognized as a major global environmental and development problem. Although great efforts have been made to prevent aquatic ecosystem degradation, the degree, extent and impacts of this phenomenon remain controversial and unclear, such as its driving mechanisms. Here, we present results from a 17-year field investigation (1998-2014) of wa...

Forest ecosystems are among the largest terrestrial carbon reservoirs on our planet earth thus playing a vital role in global carbon cycle. Presently, remote sensing techniques provide proper estimates of forest biomass and quantify carbon stocks. The present study has explored Landsat-8 sensor product and evaluated its application in biomass mapping and estimation. The specific objectives were...

2017
John E. Hobbie Gaius R. Shaver Edward B. Rastetter Jessica E. Cherry Scott J. Goetz Kevin C. Guay William A. Gould George W. Kling

Long-term measurements of ecological effects of warming are often not statistically significant because of annual variability or signal noise. These are reduced in indicators that filter or reduce the noise around the signal and allow effects of climate warming to emerge. In this way, certain indicators act as medium pass filters integrating the signal over years-to-decades. In the Alaskan Arct...

2009
F. R. FOSBERG

The great Pacific groups of atolls are such archipelagoes as the Tuamotus, Carolines, Marshalls, Gilberts, the Phoenix-Ellice group, and those scattered clusters and individual islands collectively termed the Pacific Equatorial or Line Islands. The observations forming the basis of this paper were made on visits to all these groups, except the Phoenix-Ellice and Gilberts, as well as to the Aust...

Journal: :Saudi journal of biological sciences 2012
Abdulrahman Alatar Mohamed A El-Sheikh Jacob Thomas

THIS ARTICLE HAS BEEN RETRACTED please see Elsevier Policy on Article Withdrawal (http://www.elsevier.com/locate/withdrawalpolicy). This article has been retracted at the request of the Editor-in-Chief and Author. Data processing errors have resulted in misleading conclusions. The scientific community in King Saud University has serious concerns regarding the results and the article will be res...

2014
Hongrui Ren Guangsheng Zhou

Accurate estimation of green aboveground biomass in arid and semiarid grassland is essential for a variety of studies, such as sustainable grassland management, fire risk assessment, climate change, and environmental degradation. A great need exists for the establishment of robust method for estimating green aboveground biomass in arid and semiarid grassland due to the influences of soil backgr...

Journal: :Journal of environmental management 2012
Kurt H Riitters James D Wickham Timothy G Wade Peter Vogt

The conservation value of natural vegetation is degraded by proximity to anthropogenic land uses. Previous global assessments focused primarily on the amount of land protected or converted to anthropogenic uses, and on forest vegetation. Comparative assessments of extant vegetation in terms of proximity to anthropogenic land uses are needed to better inform conservation planning. We conducted a...

Journal: :Entropy 2015
Guanghui Shi Fu Ren Qingyun Du Nan Gao

The purpose of this paper is to present and exploit fundamental information, such as semantic meanings and geographical features, of phytotoponyms (a type of toponym that includes plant names) in Western Hubei (China). Long-term vegetation degradation is also estimated. Toponym data for this study were obtained from the place names database of Hubei Province at the Civil Affairs Department of H...

Journal: :Remote Sensing 2014
Thomas P. Higginbottom Elias Symeonakis

Land degradation and desertification has been ranked as a major environmental and social issue for the coming decades. Thus, the observation and early detection of degradation is a primary objective for a number of scientific and policy organisations, with remote sensing methods being a candidate choice for the development of monitoring systems. This paper reviews the statistical and ecological...

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