نتایج جستجو برای: density of forbs
تعداد نتایج: 21193008 فیلتر نتایج به سال:
Precipitation change and grazing are the main factors influencing vegetation structure dynamics in semi-arid grassland. However, effects of precipitation variation livestock trampling on seedling emergence patterns plants remain largely unknown. In this study, an experiment with four gradients (no-trampling, light, moderate, heavy) three treatments (ambient precipitation, +30% −30% precipitatio...
The impacts of wild herbivores on cattle diet selection were investigated in an East African rangeland during August 2001 and February 2002. The study compared cattle diets in plots exclusively accessible to cattle (C) and those accessible to megaherbivores (elephants and giraffes), non-megaherbivore wild herbivores . 15 kg (zebras, hartebeests, Grant’s gazelles, oryx, elands, and buffaloes) an...
rangelands encompass 55% of iran's territory. monitoring of such resources is inevitable due to dynamic behavior and extremely high extension. scanning of land resources data by satellites facilitates monitoring the rangelands. this research was carried out to study the relationships of vegetation indices derived from irs liss-iii data with vegetation cover of tange sayyad region in the ch...
Jepson Prairie in Solano County, an outstanding example of remnant California Central Valley vernal pool and grassland habitats, is threatened by invasive exotic species. This paper describes the results of a 200-acre late-spring prescribed fire conducted at Jepson Prairie in June of 1995 and aimed at reducing the cover of an extensive infestation of Medusahead (Taeniatherum caput-medusae). Bur...
The ability of invasive plants to achieve higher relative growth rates (RGR) than their native counterparts has been widely documented. However, the mechanisms allowing invasives to achieve higher RGR are poorly understood. The objective of this study was to determine the basis for RGR differences between native and invasive forbs that have widely invaded nutrient-poor soils of the Intermountai...
Loss of plant diversity with increased anthropogenic nitrogen (N) deposition in grasslands has occurred globally. In most cases, competitive exclusion driven by preemption of light or space is invoked as a key mechanism. Here, we provide evidence from a 9-yr N-addition experiment for an alternative mechanism: differential sensitivity of forbs and grasses to increased soil manganese (Mn) levels....
Rangeland management plan is one of the major means of management and utilization of rangelands in Iran. The formulation of these plans for the rangeland users should be studied from the ecological and socio-economic points of view. One of the main envisaged activities in almost all the management plans is the grazing system. An experiment was used to study the effects of three deferred grazing...
Loss of plant diversity with increased anthropogenic nitrogen (N) deposition in 40 grasslands has occurred globally. In most cases, competitive exclusion driven by preemption of 41 light or space is invoked as a key mechanism. Here, we provide evidence from a 9-year N 42 addition experiment for an alternative mechanism: differential sensitivity of forbs and grasses to 43 increased soil manganes...
Multiple interacting factors drive recent declines in wild and managed bees, threatening their pollination services. Widespread and intensive monitoring could lead to more effective management of wild and managed bees. However, tracking their dynamic populations is costly. We tested the effectiveness of an inexpensive, noninvasive and passive acoustic survey technique for monitoring bumble bee ...
The Moroccan locust (Dociostaurus maroccanus Thunberg) is one of the most important species of locusts in Iran and many parts of the world, which causes great damage to pastures and agricultural products every year. Since a main part of the life cycle of this insect is spent in pastures, recognizing the relationship between locusts and plant properties are important in the rangeland management ...
نمودار تعداد نتایج جستجو در هر سال
با کلیک روی نمودار نتایج را به سال انتشار فیلتر کنید