نتایج جستجو برای: exclosure
تعداد نتایج: 275 فیلتر نتایج به سال:
Snowshoe hare populations in the boreal forests of North America go through 10-year cycles. Supplemental food and mammalian predator abundance were manipulated in a factorial design on 1-square-kilometer areas for 8 years in the Yukon. Two blocks of forest were fertilized to test for nutrient effects. Predator exclosure doubled and food addition tripled hare density during the cyclic peak and d...
Concentrated herbivory by elk (Cervus elaphus) can degrade vegetative communities and alter ecosystem processes. Areas severely damaged by elk are commonly protected with woven wire fence, which can exclude other animals. Complete exclusion and prevention of large mammal herbivory might not always be necessary to restore vegetative communities. We designed and evaluated a simple fence that excl...
the study of the exclosure effects on the vegetation changes undergrazing and non-grazing conditions in the rangeland areas has particularimportance in the rangeland improvement and revivification projects. theresearch was accomplished in semi-steppe khoybilehvar area, from 1999 to2005. vegetation cover was annually measured within fixed plots during transact.the results showed that during nine...
Exclosure experiments have demonstrated the effects of bird predation on arthropods. In a Mexican coffee plantation, we excluded foliage-gleaning bird and bat predators from coffee plants. Effects of bats and birds were additive. In the dry season, birds reduced arthropods in coffee plants by 30%; birds and bats together reduced arthropods by 46%. In the wet season, bats reduced arthropods by 8...
conservation and restoration of biodiversity is very important for degraded rangeland ecosystems. it is necessary to assess the potential of soil seed bank as a major source of species. in this study, the soil seed bank size and composition were compared between exclosure and grazed areas. this was done in chahar-bagh rangelands in golestan province. soil was sampled in exclosure and grazing fr...
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...
Rising temperatures due to climate change are pushing the thermal limits of many species, but how climate warming interacts with other anthropogenic disturbances such as land use remains poorly understood. To understand the interactive effects of climate warming and livestock grazing on water temperature in three high elevation meadow streams in the Golden Trout Wilderness, California, we measu...
the effect of exclosure on the changes of vegetation cover of rangelands of ahmad-abad region located in zanjan province has been studied during 2002 to 2006. three transects comprises of 60 fixed quadrate were establish within exclosure area and outside as well. the changes of vegetation cover were studied to made comparison between the changes of manipulated factors and soil elements using t ...
1. Herbivores influence the structure and composition of terrestrial plant communities. However, responses of plant communities to herbivory are variable and depend on environmental conditions, herbivore identity and herbivore abundance. As anthropogenic impacts continue to drive large declines in wild herbivores, understanding the context dependence of herbivore impacts on plant communities be...
The study of the exclosure effects on the vegetation changes undergrazing and non-grazing conditions in the rangeland areas has particularimportance in the rangeland improvement and revivification projects. Theresearch was accomplished in semi-steppe KhoyBilehvar area, from 1999 to2005. Vegetation cover was annually measured within fixed plots during transact.The results showed that during nine...
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