نتایج جستجو برای: semi steppe rangelands
تعداد نتایج: 147987 فیلتر نتایج به سال:
The aim of the study was to determine the most important environmental factors (topography, climate, and soil) affecting changes in production and canopy cover of plant variations and to prepare prediction maps, based on the most important factor, in semi-steppe rangelands of Hir-Baghrou, Ardabil province, Iran. First, by detecting the vegetation types and different classes of environmental fac...
The soil–vegetation relationships are reciprocal and fundamental for terrestrial ecosystem integrity. However, the long-term degradation of vegetation cover alters edaphic conditions, which can lead to habitats, obstructs proper functioning. This study aimed assess effects perennial steppe due overgrazing (i.e., continuous free grazing) on physicochemical characteristics soil fertility in range...
The objective of this research was to identify the vegetation-soil relationships in Nodushan arid rangelands of Yazd. 5 sites were selected for measuring the cover of plant species and soil attributes. Soil samples were taken in 0-10 and 10-80 cm layers. The species studied were Salsola tomentosa, Salsola arbuscula, Peganum harmala, Zygophylum eurypterum and Eurotia ceratoides. Canonical corres...
For most ecosystems, net ecosystem exchange of CO2 (NEE) varies within and among years in response to environmental change. We analyzed measurements of CO2 exchange from eight native rangeland ecosystems in the western United States (58 site-years of data) in order to determine the contributions of photosynthetic and respiratory (physiological) components of CO2 exchange to environmentally caus...
Medusahead (Taeniatherum caput-medusae (L.) Nevski) is an exotic annual grass invading rangelands in the western United States. Medusahead is a serious management concern because it decreases biodiversity, reduces livestock forage production, and degrades the ecological function of rangelands. Despite the obvious importance of ranchers as partners in preventing and managing medusahead in rangel...
this study sought to develop a decision support system (dss) for assisting range managers to detect range condition and make informed decisions about feridan county rangelands. all plant species frequencies were measured in 31 range sites with various grazing histories using step point method. four hundred points along four perpendiculars 30 meters transects were measured in each site and grazi...
Degradation of plant patches is considered as one of the indices for rangeland degrading health condition. Investigating the accuracy of triple indices (infiltration, stability and soil nutrient cycle) presented by LFA method seems necessary to determine its efficiency in semi-arid areas with the least cost. This study aims to investigate the role of vegetative species and growing forms on soil...
To determine readiness of range for entry and exit livestock, achieving information such as vegetation characteristics, grazing behavior, soil moisture content and Environment temperature, is necessary. Therefore, in this study, the major plants phenological stages, Monthly temperature and precipitation data and Estimating soil moisture were investigated in the 4-year period (1386-1389). The st...
A review of the ground beetles of the Ukrainian fauna is given. Almost 750 species from 117 genera of Carabidae are known to occur in the Ukraine. Approximately 450 species of ground beetles are registered in the Carpathian region. No less than 300 species of ground beetles are found in the forest zone. Approximately 400 species of Carabidae present in the forest-steppe zone are relatively simi...
The study of vegetation dynamics under grazed and non-grazed rangelands is one of the most important prerequisites for range improvement. In this research, vegetation composition and the vegetation functional groups were compared in an exclosure site (livestock excluded for six years) and grazed area in semi-steppe rangelands in Tehran province. Systematic random sampling technique through the...
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