نتایج جستجو برای: diversity of vegetation density
تعداد نتایج: 21214870 فیلتر نتایج به سال:
livestock grazing and rangelands fire are important ecological disturbances influencing the vegetation and soil properties in rangelands ecosystem. this study was conducted to determine the effects of different burned treatments and distances from the water sources on some soil and vegetation properties of rangelands ecosystem. the experiment was conducted in lashgar dar rangelands. vegetation ...
Overgrazing, via harvesting of forage species and decrease the other herbs, is of progressive factors in biodiversity destroying. In order to investigate the animal grazing impacts on changing of plant structure and diversity, we selected the comparison between this effect with exclosure area, and proving of the excluded area effects on plant diversity; two sites of Kojour rangeland, Mazandran ...
this study was performed in second half of year 2009.for bird counting , monthly from septamber until march 2009. total counted birds in maroon lake were (971). maximum number of counted birds was in february (191) and minimum of counted was in septamber (95). total counted birds in jaizan were (385. maximum number of the counted bird was in february (84) and minimum of counted (52) was in ja...
In arid and semi-arid environments like the rest parts of South Africa, the state of vegetation density in catchments is an important indicator of the state of the environment. Climate variability coupled with different anthropogenic activities could affect vegetation cover at varying levels. The Upper Molopo River Catchment (UMRC) in the North West Province of South Africa is under this combin...
OBJECTIVES Species Distribution Models (SDMs) are used to produce predictions of potential Leguminosae diversity in West Central Africa. Those predictions are evaluated subsequently using expert opinion. The established methodology of combining all SDMs is refined to assess species diversity within five defined vegetation types. Potential species diversity is thus predicted for each vegetation ...
it is not possible to understand developments of a country’s culture and civilization without knowing his believes and myths. whether it is north or south, east or west, planes or mountains, sahara or deserts, here in iran every corner includes valuable and precious treasures which are known all over the world, and cultural – historical objects which are found here adorn all well known museums...
Aim To test six hypotheses that could explain or mediate the positive correlation between human population density (HPD) and bird species richness while controlling for biased sampling effort. These hypotheses were labelled as follows: productivity (net primary productivity, NPP); inherent heterogeneity (diversity of vegetation types); anthropogenic heterogeneity (diversity of land uses); conse...
Biodiversity conservation and ecosystem-service provision will increasingly depend on the existence of secondary vegetation. Our success in achieving these goals will be determined by our ability to accurately estimate the structure and diversity of such communities at broad geographic scales. We examined whether the texture (the spatial variation of the image elements) of very high-resolution ...
Abstract Background and objectives: Fire as a frequent phenomenon in rangelands and because of its complicated and different effects on natural ecosystems, has great importance. Awareness of such fire effects on vegetation cover in point of rangeland management after fire is important and helps better Understanding and sustainable management of rangelands. Changing in plant structure and compo...
Over the past two decades, degradation damage has increased in natural ecosystems. This research focuses solely on the degradation of soil and vegetation cover in Sorkheh Eshpar National Park. For this purpose, some physical properties of the soil (specific gravity and true porosity, moisture content, a percentage of pebbles, acidity and conductivity and soil texture) were measured. Also, the d...
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