نتایج جستجو برای: vegetation

تعداد نتایج: 47633  

2005
JACOB R. GOHEEN JAMES H. BROWN

Evidence from numerous studies suggests that species richness is an emergent property of local communities. The maintenance of species richness, despite changes in species composition and environmental conditions, requires compensatory colonization and extinction events with species coming from a regional pool. Using long-term data from a rodent community in the Chihuahuan Desert, we use random...

2009
Aasim I. Padela

Multiculturalism and its associated plurality of value systems is rapidly becoming the norm in modern medical practice. Given this increasing diversity, greater emphasis upon cultural and ethical competence in physician training is necessary in order to provide culturally sensitive and ethically sound care. Religious values shape ethical codes and are expressed in the cultural norms of subcommu...

2013
Richard Oslisly Lee White Ilham Bentaleb Charly Favier Michel Fontugne Jean-François Gillet David Sebag

Central Africa includes the world's second largest rainforest block. The ecology of the region remains poorly understood, as does its vegetation and archaeological history. However, over the past 20 years, multidisciplinary scientific programmes have enhanced knowledge of old human presence and palaeoenvironments in the forestry block of Central Africa. This first regional synthesis documents s...

Journal: :Environmental monitoring and assessment 2006
Pei-Yu Chen Gunar Fedosejevs Mario Tiscareño-López Jeffrey G Arnold

Although several types of satellite data provide temporal information of the land use at no cost, digital satellite data applications for agricultural studies are limited compared to applications for forest management. This study assessed the suitability of vegetation indices derived from the TERRA-Moderate Resolution Imaging Spectroradiometer (MODIS) sensor and SPOT-VEGETATION (VGT) sensor for...

2006
Michael Weiss Gabriella Moroiu Ping Zhao

The goal of this paper is to document the evolution of a portfolio of related open source communities over time. As a case study, we explore the subprojects of the Apache project, one of the largest and most visible open source projects. We extract the community structure from the mailing list data, and study how the subcommunities evolve, and are interrelated over time. Our analysis leads us t...

ژورنال: علوم آب و خاک 2010
امیرحسین قره‌شیخلو, , حمیدرضا کریم‌زاده, , محمدرضا وهابی, ,

The purpose of this study was to compare the physical and chemical characteristics of soils covered with vegetation and soils without vegetation in Dagh-e- Sorkh Ardestan area.To achieve the goal, first the vegetation was classified using physiognomic method, and for each vegetation type, the distinctive area was specified for soil and vegetation sampling. Vegetation sampling was done by strati...

2016
Rubina Parveen Subhash Kulkarni V. D. Mytri S. Bharathi V. Shreyas R. Anirudh S. Sanketh P. D. Shenoy K. Venugopal

Extraction of vegetation is an important step for agricultural, forest and greenery mapping. The proposed method examines the complex process of land cover vegetation pattern classification using an IRS-1C LISS III image. Pre-processing was done by employing partial differential equation (PDE). Normalized differential vegetation index (NDVI) was applied to separate vegetation features from the ...

Gholamreza Zehtabian Hasan Ahmadi Hossein Azarnivand Saeideh Kalantari

One of the influential tools concerning the rangeland and vegetation sciences isthe technology of remote sensing and satellite data. Satellite data have played essentialroles in preparing the needed information for studying the vegetation. Vegetation has beenwidely recognized as one of the best indicators for determining the land conditions. Usingvegetation indices is one of the techniques of r...

2012
Farooq Ahmad

To enhance the vegetation signal in remotely sensed data and provide an approximate measure of live green vegetation, a number of spectral vegetation indices have been developed to estimate biophysical parameters of vegetation. The sensitivity of the normalized difference vegetation index (NDVI) to the soil background and atmospheric effects has generated an increasing interest in the developme...

2017
Nannan Gao Jihua Zhou Xiaolong Zhang Wentao Cai Tianyu Guan Lianhe Jiang Hui Du Dawen Yang Zhentao Cong Yuanrun Zheng

Vegetation patterns and spatial organization are influenced by the changing environmental conditions and human activities. However, the effect of environment on vegetation at different vegetation classification levels has been unclear. We conducted an analysis to explore the relationship between environment and vegetation in the land use/land cover (LULC), vegetation group, vegetation type, and...

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