نتایج جستجو برای: vegetation type

تعداد نتایج: 1384618  

2010
A. Ono K. Kajiwara Y. Honda

For the analysis of vegetation areas using satellites, a variety of vegetation indexes such as NDVI and EVI have been developed. However, most indexes have weak response to grasping the type and quality (the growth state and situation) of vegetation. To grasp these vegetation characteristics, we have developed new vegetation indexes, i.e. shadow index (SI) and water stress trend (WST). We estim...

Journal: :مرتع و آبخیزداری 0
محمدعلی زارع چاهوکی دانشیار دانشکده منابع طبیعی دانشگاه تهران لیلا خلاصی اهوازی کارشناس ارشد مرتع‏داری دانشگاه تهران حسین آذرنیوند استاد دانشکده منابع طبیعی دانشگاه تهران

the aim of this study was providing plant species predictive habitat models by using logisticregression method. for this purpose, study area conducted in north east rangelands of semnanmodeling vegetation data in addition to site condition in formation including topography, and soil wasprepared. sampling was done within each unit of sampling parallel transects and 1 vertical transectwith 750m l...

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THIS ARTICLE HAS BEEN RETRACTED please see Elsevier Policy on Article Withdrawal (http://www.elsevier.com/locate/withdrawalpolicy). This article has been retracted at the request of the Editor-in-Chief and Author.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...

Journal: :desert 2010
hosein azarnivand hamed joneidi jafari sh. nikoo mohamad zare chahouki a. malekian

abstract the objective of current research is to investigate distribution patterns of vegetation types and its relation with environmental factors in southern margin of haj aligholi kavir of damghan. three vegetation types including halecnemum strobilaceum, sedlitzia rosmarinus and artemisia sieberi were studied in marginal arid regions and uplands of the study area. firstly, geographic locatio...

Journal: :مجله مرتعداری 0

in this study, we applied classification methods and geographic information system(gis) techniques to identify vegetation structures in andevar rangelands. homogenous work unit maps were produced by overlaying the layers of slope, aspect and digital elevation. totally 95 homogenous units were determined in which the field studies were carried out. vegetation sampling was done in 69 transects an...

Journal: :journal of agricultural science and technology 2014
m. masoudi

the entire land in the southern iran faces problems arising out of various types of land degradation, of which the vegetation type forms one of the major ones. the payab basin (522,470 ha), which covers the lower reaches of mond river, was chosen for a test risk assessment of this type. the different kinds of data for indicators of vegetation degradation were taken from the records and publishe...

Desertification process has always been led to destruction of vegetation cover and soil and water resources that can occur in different climatic conditions, the intensity of which depends on the natural conditions of the region. Due to the increase in destruction of vegetation as one of the most important consequences of desertification, monitoring the changes and assessment of their trends are...

Journal: :مرتع و آبخیزداری 0
محسن نقیلو کارشناس دانشکده منابع طبیعی، دانشگاه تهران، ایران محمد جعفری استاد دانشکده منابع طبیعی، دانشگاه تهران، ایران محمد طهمورث 3 کارشناس ارشد آبخیزداری، ایران اصغر کهندل استادیار جهاد دانشگاهی واحد تهران، ایران فریناز همدانیان 5 فارغ التحصیل کارشناس ارشد مرتعداری، ایران

the purpose of this research was to investigate the relationship between vegetation cover and soil characteristics in order to determine the most important soil factors which affect on quantitative variations and types of vegetation cover in the study area. the study area is located in west of tehran province and southeast of hashtgerd, next to najm-abad village. after field studies, the index ...

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