نتایج جستجو برای: vegetation cover density and type
تعداد نتایج: 17062927 فیلتر نتایج به سال:
in new management approaches, in the organizations with inflexible structure, existing of red tapes and interruptions caused by limitations and also non-compliance with environmental changes, create demotivation among staff. with regard to the influence of job motivational potential and its relationship to the type of organizational structure( enabling and dissuasive), the goal of this research...
Vegetation plays an important role in stabilizing the soil and decreasing fluvial erosion. In certain cases, vegetation increases the accumulation of fine sediments. Efficient and accurate methods are required for mapping and monitoring changes in the fluvial environment. Here, we develop an area-based approach for mapping and monitoring the vegetation structure along a river channel. First, a ...
The protection and improvement of natural resources especially for desert vegetation need a comprehensive recognition of natural resources and relationship on Soil characteristics. One of the most important species growing in sabzevar desert is Stipagrostis pennata and in the current research the relationship between the physicochemical properties of the soils and growth characteristics of the ...
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 aim of this study was to assess the regional effects of fire on the surface cover and forage production of mountainous rangelands of Delfan County, Lorestan province, Iran. The fire took placed in June 2007 with significant effects on the vegetation characteristics in the study area. Four fire affected sites were selected for sampling and a close area without fire was considered as control....
Forty years after conversion from chaparral to perennial veldt grass in the San Dimas Experimental Forest, we compared land surface and soil properties between areas of the two vegetation types. Our objective was to evaluate the impact of this vegetation conversion on the soil physical properties likely to impact zero-order watershed hydrology. In three watersheds of each vegetation type, surfa...
Knowledge of rangeland vegetation characteristics as well as factors affecting it in environmental planning, land management and sustainable development is very important. However, regional and up-to-date maps of pasture vegetation cover are not always available. In this study, in order to plot the vegetation cover percentage of the rangelands and monitor its changes in drought and wet periods,...
a better understanding of rangeland vegetation cover and its variation in different years basedon wetness and droughtiness fluctuations is a great importance. economical priority setting ofrangelands is based on variations in rainfall and drought patterns, because it yields to bettercharacterization of vegetative cover. yet a comprehensive and continuous monitoring ofvegetative cover of rangela...
The Moroccan locust (Dociostaurus maroccanus Thunberg) is one of the most important species of locusts in Iran and many parts of the world, which causes great damage to pastures and agricultural products every year. Since a main part of the life cycle of this insect is spent in pastures, recognizing the relationship between locusts and plant properties are important in the rangeland management ...
Soil physical properties have an important role on vegetation growththrough affecting the development of root system. The aim of this study was toinvestigate the trampling effect of livestock grazing on soil physical properties andvegetation cover changes. The experiment was conducted on three range conditionsites (Reference, Key and Critical area) with ten frequencies in HosseinabadeKudistan i...
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