نتایج جستجو برای: vegetation cover
تعداد نتایج: 148562 فیلتر نتایج به سال:
the preparation of vegetation cover maps by used the land inventory and a traditional method has a lot of cost and time. but today, remote sensing is one of the main sources of data collection and information production for study and monitoring land resources, and was efficient tools for providing quickly and timely data and information needs for program planning in the natural resource filed. ...
As ecosystem engineers, prairie dogs (Cynomys spp.) physically alter their environment, but the mechanism by which these alterations affect associated faunal composition is not well known. We examined how rodent and vegetation communities responded to prairie dog colonies and landcover at the Cimarron National Grassland in southwest Kansas, USA. We trapped rodents and measured vegetation struct...
Here, I describe the geographical distribution of the savanna types in Namibia and identify the factors controlling the occurrence of each savanna type in relation to the amount of annual precipitation and the various physiographical regions, including the mopane ( Colophospermum mopane) area. The different types of savanna can be distinguished on the basis of the leaf habits of the dominant ve...
Climatic controls on fluvial landscapes are commonly characterized in terms of mean annual precipitation. However, physical erosion processes are driven by extreme events and are therefore more directly related to the intensity, duration, and frequency of individual rainfall events. Climate also influences erosional processes indirectly by controlling vegetation. In this study, we explore how i...
This research was aimed to simulate and prioritize the effective factors on water erosion using USLE-M in the system dynamic model. In this integrated model, by using the system dynamic simulation software (Vensim), all variables and factors involved in erosion and soil loss were considered according to the USLE-M model. After model implementation, the estimated values and observations were com...
Studies on vegetation changes of rangelands under grazed and non-grazedconditions are of great importance in the range management planning programs. To determinethe change process of vegetation, this study was performed in Inche Shorezar site of Golestanprovince for nine years (1997-2005). The vegetation parameters were measured every year inseveral fixed plots inside and adjacent of exclosures...
Methods that are more cost-effective and objective are needed to detect important vegetation change within acceptable error rates. The objective of this research was to compare visual estimation to three new methods for determining vegetation cover in the sagebrush steppe. Fourteen management units at the US Sheep Experiment Station were identified for study. In each unit, 20 data collection po...
some chemical characteristics of root, shoot and litter of index species such as salsola rigida, artemisia sieberi and stipa barbata commonly used in rangeland development projects were evaluated and compared. chemical properties of soil under and between the above mentioned species were also studied. for this purpose, vegetation types of stipa barbata and artemisia sieberi - salsola rigida wer...
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....
In dry lands, semi-circular bund has been considered as a management practice used to restore the ecological revival in terms of vegetation enrichment and soil amelioration. This study was conducted to investigate the effects of semi-circular bunds on vegetation cover and some soil properties in Koteh rangeland, Sistan and Baloochestan province, Iran (2014). Adjacent to the semi-circular bund a...
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