نتایج جستجو برای: vegetation density

تعداد نتایج: 453936  

2004
J. NICHOL

Very high resolution (VHR) satellite remote sensing systems are now capable of providing imagery with similar spatial detail to aerial photography, but with superior spectral information. This research investigates the hypothesis that it should be possible to use multispectral IKONOS images to quantify urban vegetation, obtaining similar accuracy to that achieved from false colour aerial photog...

Ali Ashraf Jafari Hossein Arzani Mohammad Jafari Sedigheh Zare Kia Seyyed Akbar Javadi

This study aims to assess the effect of grazing intensity on vegetation structure, soil nutrient concentrations and soil physical properties. The study was carried out in steppe rangelands of Saveh, Markazi province, Iran. Four sites with four grazing intensities including very high, high, moderate and non-grazed with the same ecological conditions were selected. To study various vegetation and...

Effect of fire on phyto-sociology of understorey vegetation in chir pine forests of three different silvological characteristics was compared with pure grassland. 15 grasses, 1 sedge, 5 legumes and 21 non-legumes were recorded in the four study sites. Floristic composition gradually increased from June to August and then declined slowly by October in all the plots. Maximum number of species wa...

2012
Nicole M. Czarnomski Desireé D. Tullos Robert E. Thomas Andrew Simon

Vegetation growing on the surface of a streambank has been shown to alter the shear stresses applied to the boundary, but basic questions remain regarding the influence of vegetation and streambank configurations on near-bank hydraulics. In the present study, Froudescaled flume experiments were used to investigate how changes in vegetation density (ratio of frontal area to channel area, includi...

Biodiversity is one of the important concepts in ecology and vegetation management, and plays an important role in the health, production, and evaluation of ecosystems. Species diversity is a major part of biodiversity and one of the most important parameters of ecosystem changes. In this research, the data of the rangeland evaluation different climate zones of Isfahan province were used in fiv...

Journal: :journal of agricultural science and technology 2014
r. erfanzadeh r. shahbazian h. zali

seed bank is a central topic for plant community restoration. we determined the potential and regeneration capacity of soil seed banks of woody plant patches in conservation of the vegetation in an alpine habitat, since vegetation has completely disappeared in some sites by intensive grazing in the habitat. the study was done in mountainous area of alborz in iran. a total of 20 individual shrub...

Journal: :محیط زیست طبیعی 0
علی جعفری استادیار دانشکدۀ منابع طبیعی و علوم زمین، دانشگاه شهرکرد زهرا آرمان کارشناس ارشد جنگلداری، دانشکدۀ منابع طبیعی و علوم زمین، دانشگاه شهرکرد

this paper aims to detect occurred changes in vegetation cover of forested helen protected area using extracted ndvis from bi-temporal multispectral images of landsat tm. to do so, at first forest areas with low and moderate density cover were identified and separated on land use map. then preprocessing applications including radiometric corrections were done on both 1990 and 2009 images. also ...

Journal: :journal of rangeland science 2012
sedigheh zare kia hossein arzani mohammad jafari seyyed akbar javadi ali ashraf jafari

this study aims to assess the effect of grazing intensity on vegetation structure, soil nutrient concentrations and soil physical properties. the study was carried out in steppe rangelands of saveh, markazi province, iran. four sites with four grazing intensities including very high, high, moderate and non-grazed with the same ecological conditions were selected. to study various vegetation and...

The assessment of relationships between satellite-derived vegetation indices and meteorological drought improves our understanding of how these indices respond to climatic changes. The combination of climate data and the Normalized Difference Vegetation Index (NDVI) product of Moderate Resolution Imaging Spectroradiometer (MODIS) imagery provided an opportunity to evaluate the impact of d...

2015
Michael G. Walsh MA Haseeb

Ebola virus disease (EVD) is an emerging infectious disease of zoonotic origin that has been responsible for high mortality and significant social disruption in West and Central Africa. Zoonotic transmission of EVD requires contact between susceptible human hosts and the reservoir species for Ebolaviruses, which are believed to be fruit bats. Nevertheless, features of the landscape that may fac...

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