Spectral vegetation indices have been used extensively INTRODUCTION to predict ecological variables, such as percent vegetation On 18 May 1980, Mount St. Helens in the State of cover, above-ground biomass, and leaf-area index. We exWashington erupted with catastrophic, landscape-scale amined the use of various vegetation indices and multiple effects (Lipman and Mullineaux, 1981). In a mere 10 l...

land cover is one of basic data layers in geographic information system for physical planning and environmentalmonitoring. digital image classification is generally performed to produce land cover maps from remote sensing data,particularly for large areas. in the present study the multispectral image from irs liss-iii image along with ancillary datasuch as vegetation indices, principal componen...

Soil and water resources management of rivers has an important role because of direct relation withdifferent systems such as earth, life, social and people. Although the use of vegetation cover inbioengineering and biological stabilization and also soil and water resources management projects hasmany advantages, but improper methods of design and implementation cause hydraulic specificationsof ...

The objective of this study was to assess the relationship betweenvegetation, landform and physicochemical properties of soil. At the first terrainmap unit were provided using the landsat thematic mapper (TM) satellite images,aerial photograph, topographical and geology map. Field sampling was done in therepresentative area using plot sampling. 104 plots 100 m2 were sampled in eachplot landform...

the purpose of this research is investigation of relationship between vegetation cover and soil characteristics and determination of the most important soil factor that effects on quantity variations and kinds of vegetation cover in the study area. the study area is located in west of tehran province and south eastern of hashtgerd, next to najm-abad village. after field study, the index vegetat...

the study of the exclosure effects on the vegetation changes undergrazing and non-grazing conditions in the rangeland areas has particularimportance in the rangeland improvement and revivification projects. theresearch was accomplished in semi-steppe khoybilehvar area, from 1999 to2005. vegetation cover was annually measured within fixed plots during transact.the results showed that during nine...

The distribution and abundance of mosquito larvae in a freshwater marsh were determined during a low water period in the late summer. Culex tarsalis larval abundance was significantly associated with the percent cover by Typha spp. root masses and Typha spp. stem density in 1-m2 quadrants. Larval mosquito abundance was not significantly related to bulrush (Scirpus californicus) stem density, po...

Global climate has changed over the past century. Precipitation amounts and intensities are increasing. In this study we investigated the response of seven soil erosion models to a few basic precipitation and vegetation related parameters using common data from one humid and one semiarid watershed. Perturbations were made to inputs for rainfall intensities and amounts, and to ground surface cov...

Seasonal changes over 2 years (2004–2006) in soil moisture content ( v) of frozen alpine frost meadow soils of the QinghaiTibet plateau permafrost region under three different levels of vegetation cover were investigated. Vegetation cover and air temperature changes had significant effects (synergistic effect) on v and its distribution in the soil profile. During periods of soil freezing or tha...