نتایج جستجو برای: vegetation cover density and type
تعداد نتایج: 17062927 فیلتر نتایج به سال:
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...
The rangeland in the Khangai mountain region in Mongolia has degraded for the last decades mainly because of overgrazing and climate change. Livestock production is important part of the economy and is based on natural rangeland. In this research we seek to elucidate the influence of five years (2004-2009) of protection from grazing on vegetation cover of different degradation levels of Fes...
For studying vegetation cover in Choghakhor wetland located in Chaharmahal-o-Bakhtiari province (W Iran), some zones of vegetation life forms were determined and also digitized in order to produce the primary map of plant cover by using LISS-IV sensor of IRS satellite with the spatial resolution of 5.8 m. As aquatic plants in Choghakhor wetland were fully grown, homogeneity or heterogeneity of ...
Historically, desert drainages of the American southwest supported productive riverine wetlands (ciénegas). Region-wide erosion of ciénegas during the late 19th and early 20th century dramatically reduced the abundance of these ecosystems, but recent reestablishment of wetlands in Sycamore Creek, Arizona, USA, provides an opportunity to evaluate the mechanisms underlying wetland development. A ...
Introduction: One of the ways of restoration and reclamation of damaged rangeland is to use different methods of rain harvesting such as pitting, counter furrowing, flood spreading, small arc basins system and etc., along with the reduction of runoff, it increases the soil moisture content and thus increases vegetation cover. Biodiversity is most commonly used to describe the number of species....
Studying MODIS Satellite Data Capability to Prepare Vegetation Canopy Map in Qazvin Plain Rangelands
Using satellite imagery is a reasonable option to overcome the field visits problems and limitations to evaluate the vegetation cover over the years. The present research has conducted to specify the percentage of vegetation cover of rangelands using Geographic Information System (GIS) and vegetation indices. The study area is located in Qazvin plain rangelands, Iran. In this study, the MODIS s...
Improper use of natural resources, especially soil, causes its degradation and severe soil erosion. Water erosion is an important factor causing soil degradation. Land use change of pasture would result in severe soil erosion mainly due to the reduction of vegetation cover and also surface soil disturbance. The objectives of this study were to estimate the amount of sediment, runoff and nutrien...
Persian juniper and Pistachio are grown in low density in the rangelands of North-East of Iran. These rangelands are populated by evergreen conifers, which are widespread and present at low-density and sparse shrub of pistachio in Iran, that are not only environmentally but also genetically essential as seed sources for pistachio improvement in orchards. Rangelands offer excellent opportunities...
Exclusion and not using of rangeland in the long term affects the composition and homogeneity of vegetation and consequently leads to the improvement of plants status. In this study, the characteristics and structural changes of the rangeland of Gonbad, Hamadan province, Iran, in 2014 (after 20 years of enclosure) were evaluated using Braun-Blanquet plot, Phytosociology and multivariate analysi...
the present study investigated construct equivalence of multiple choice (mc) and constructed response (cr) item types across stem and content equivalent mc and cr items (item type ‘a’), non-stem-equivalent but content equivalent mc and cr items (item type ‘b’), and non-stem and non-content equivalent mc and cr items (item type ‘c’). one hundred seventy english-major undergraduates completed mc ...
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