نتایج جستجو برای: vegetation density

تعداد نتایج: 453936  

حجتی, سید محمد, میرزایی زاده, وحید, نیک نژاد, مریم,

In order to map the forest canopy density Bivareh Ilam Landsat 8 satellite data of 22 July 2014 and FCD model was used. The FCD of four indicators of vegetation, soil, shade and the heat index by applying a suitable threshold was and the density of vegetation and forest canopy density map based on FCD in percent respectively. Forest density map obtained, according to the classes provided by the...

جباری, سمیه , جعفری, رضا, خواجه‌الدین, سید جمال‌الدین , سلطانی, سعید,

The objective of the present study was to investigate the pasture vegetation changes using satellite data in Semirom, Isfahan province. This study was conducted in 2004 as a wet year and 2009 as a dry year. The WiFS and AWiFS satellite images were acquired and used for the year 2004 and 2009, respectively. First, the vegetation percentage was simultaneously measured in the two years. Then, cons...

2012
L. Nehal A. Khaldi

Vegetation growing in the water along rivers plays an important role on the hydrodynamic behavior, on the ecological equilibrium and on the characteristics of the river. It has effects on the flow resistance and, as a result, has a large impact on water levels. The influence of non-submerged vegetation on flow is not so clear as yet; it needs to be further studied. The Acorus Calmus L is a kind...

2013
Denise C. McGregor Sarah E. Kerr Andrew K. Krockenberger

Koalas are an iconic species of charismatic megafauna, of substantial social and conservation significance. They are widely distributed, often at low densities, and individuals can be difficult to detect, making population surveys challenging and costly. Consequently, koala population estimates have been limited and the results inconsistent. The aims of this study were to estimate the distribut...

2012
C. Guilherme Becker David Rodriguez Ana V. Longo Amanda L. Talaba Kelly R. Zamudio

Habitat loss and chytridiomycosis (a disease caused by the chytrid fungus Batrachochytrium dendrobatidis - Bd) are major drivers of amphibian declines worldwide. Habitat loss regulates host-pathogen interactions by altering biotic and abiotic factors directly linked to both host and pathogen fitness. Therefore, studies investigating the links between natural vegetation and chytridiomycosis requ...

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: :Brazilian journal of biology = Revista brasleira de biologia 2008
T C Rocha-Pessôa A F Nunes-Freitas L Cogliatti-Carvalho C F D Rocha

We studied some ecological parameters such as richness, abundance, density, biomass and variation in species composition in four vegetation zones and in a zone with anthropic disturbance in the Massambaba Restinga in Arraial do Cabo, Rio de Janeiro State. We sampled 100 plots of 100 m(2) (10 x 10 m) recording the bromeliad species and their abundance. We found a total of seven bromeliad species...

2010
T. Stoesser

This paper presents results of several large-eddy simulations LES of turbulent flow in an open channel through staggered arrays of rigid, emergent cylinders, which can be regarded as idealized vegetation. In this study, two cylinder Reynolds numbers, RD =1,340 and RD=500, and three vegetation densities are considered. The LES of the lowest density and at RD=1,340 corresponds to a recently compl...

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