نتایج جستجو برای: Exclosure
تعداد نتایج: 275 فیلتر نتایج به سال:
A Water Exclosure Treatment System (WETS) is developed and installed to minimize the occurrence of beach closures due to algae and Escherchia coli (E. coli) in an inland lake. WETS consists of an "exclosure" sub-system with a five-sided polypropylene, barrier that excludes offshore lake contaminated water from the swimming area. Inside the exclosure, water is pumped to a portable filtration-ult...
Mimosa pudica is the most abundant and problematic invasive species in tropical pastures. This study investigates the effects of two cattle grazing systems, long-term moderate grazing (LTG, 2.7 animal unit/ha/yr for 33 years) and short-term heavy grazing (STG, 5 animal unit/ha/yr for 2 years) compared with ungrazed exclosure pasture on the invasion of M. pudica and its relationship with herbage...
Over the last three decades, livestock exclosure research has emerged as a preferred method to evaluate the ecology of riparian ecosystems and their susceptibility to livestock impacts. This research has addressed the effects of livestock exclusion on many characteristics of riparian ecosystems, including vegetation, aquatic and terrestrial animals, and geomorphology. This paper reviews, critiq...
—In 2001, predator exclosures were used to protect nests of the Western Sandpiper ( Calidris mauri ) in western Alaska. During the exclosure experiment, nest contents in exclosures had significantly higher daily survival rates than control nests, however, late in the study predators began to cue in on exclosures and predate the nest contents. An Arctic Fox ( Alopex lagopus ) dug under one exclo...
Wild pigs were established around coastal Spanish settlements in California in the 1800s and expanded over the last century by hunting introductions, domestic releases, and natural dispersal. The current distribution of wild pigs is closely associated with oak woodlands where foraging and rooting by the species may impinge on many native species. Rooting disturbance by wild pigs may be especial...
Hyperaccumulation of Ni by plants is hypothesized to function as an elemental defense against herbivores and pathogens. Laboratory experiments have documented toxic effects to herbivores consuming high-Ni plant tissues, but this paper reports the first experiment to examine the defensive effectiveness of Ni hyperaccumulation under field conditions. The experiment was conducted at an ultramafic ...
Benthic grazing strongly controls periphyton biomass. The question therefore arises whether benthic grazing could be used as a tool to reduce excessive growth of periphyton in nutrient-enriched rivers. Although benthic invertebrate grazers reduce the growth of periphyton, this is highly context dependent. Here we assessed whether the only obligate herbivorous fish in European rivers, the common...
Chronic browsing by Odocoileus virginianus (White-tailed Deer) has potential to alter the life history of trees within Mid-Atlantic forests, including seedling size and abundance in the short term to overstory composition in the long term. Most studies quantify the effects of deer browse using small plots (<1 ha) and short time frames (<10 years), which may misrepresent larger-scale and longer-...
The rangelands, as one of the largest dynamic biomes in the world, have very capabilities. Regulation of greenhouse gases in the Earth's atmosphere, particularly carbon dioxide as the main these gases, is one of these cases. The attention to rangeland, as cheep and reachable resources to sequestrate the carbon dioxide, increases after the Industrial Revolution. Rangelands comprise the large par...
to compare the seed characteristics in accessions of atriplex canescens under exclosure and non-exclosure conditions, two even-aged sites were selected with an area of 400 ha as the exclosure and 1000 ha as non-exclosure area. to conduct the study, 30 species were randomly selected in autumn 2009 in reference area of the sites and seeds were collected. some important seed characteristics were s...
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