نتایج جستجو برای: total vegetation cover decreased by 362
تعداد نتایج: 7530927 فیلتر نتایج به سال:
Interpretation of large-scale color infrared and color aerial photography can be a laborand cost-effective means to make inventory of and monitor rangelands while maintaining accuracy. Ground measurements of total vegetation cover, tree, shrub and cacti cover at Organ Pipe Cactus National Monument were taken in 1975 and 1984. Estimates of ground vegetation cover made using large scale (1:1200) ...
Planting shrub seedlings under oil mulches has frequently been used for stabilizing mobile sands in Iran for during the last three decades. Sandy desert of Samad Abad, Sarakhs, northeast Iran, has been fixed by cultivating seedling of Haloxylon aphyllum under the oil mulches. Therefore this study was designed to investigate the effects of the sand fixation project on soil and vegetation propert...
The spatially explicit and mechanistic model TREEGRASS was used to test the effects of tree density, tree spatial distribution, and tree size distribution on radiation absorption, net primary production (NPP), and, water fluxes for a West African savanna . The model has previously been shown to adequately predict radiation absorption, production, and soil water balance in humid savannas . Using...
Rangeland ecosystems in arid and semiarid regions strongly were influenced by climatic factors and their kind of exploitation of management. These changes usually occur in combination and structure of vegetation over time. Because understanding the dynamics of pasture can choose the appropriate management practices and proper help, The changes of vegetation in desert ecosystem of Jajarm area, b...
I conducted small-mammal trapping surveys on a desert scrub restoration site in Palm Springs, California, to document concomitant recovery of the rodent community. These surveys were conducted following quantitative vegetation sampling efforts that indicated that a predefined successful restoration criterion of 15% total shrub cover had been met throughout most of the area. But shrub cover, nat...
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...
The goals of this paper are to assess feasibility of using total concentration (TPC) of phytoliths in modern soils and morphotypes in soil assemblages to infer paleovegetation cover and composition. We sampled from undisturbed grassland sites with different values of shrub and grass cover in the Columbia Basin, interior Pacific Northwest, USA. Phytolith concentration in soils were measured and ...
The present study discusses a method used to produce updated information about vegetation cover in arid and semi-arid zones, using RS data and GIS technique. In this method, Landsat ETM+ data in 2002 was collected in an area of about 60000 ha in Nodoushan basin, Yazd, Iran. To collect the necessary ground data, 50 sites of different vegetation types were selected and the percentage of vegetatio...
Spiders were sampled at Mpala Research Centre, Laikipia, Kenya by pitfall-trapping and sweep-netting from May 2001 to July 2002, at a Kenyan Long-term Exclosure Experiment. The aim was to establish species composition, checklist and examine spider responses to disturbances caused by cattle, megaherbivores (giraffe and elephants) and mesoherbivores (other ungulates) by looking at three levels of...
Albert, D.A. and Barnes, B.V., 1987. Effects of clearcutting on the vegetation and soil of a sugar maple-dominated ecosystem, western Upper Michigan. For. Ecol. Manage., 18: 283-298. The effects 50 years after clearcutting on the vegetation and soil of an ecosystem type dominated by sugar maple (Acer saccharum) were studied at four locations along the boundaries of the Sylvania Recreation Area ...
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