نتایج جستجو برای: short time exclosure

تعداد نتایج: 2216279  

Journal: :Science 2008
Kimberly Williams-Guillén Ivette Perfecto John Vandermeer

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...

Journal: :مرتع و آبخیزداری 0
فاطمه سالاریان کارشناس ارشد مرتعداری، دانشکده منابع طبیعی، دانشگاه علوم کشاورزی و منابع طبیعی ساری جمشید قربانیان دانشیار دانشکده منابع طبیعی، دانشگاه علوم کشاورزی و منابع طبیعی ساری قدرت الله حیدری استادیار دانشکده منابع طبیعی، دانشگاه علوم کشاورزی و منابع طبیعی ساری نصرت االه صفائیان استاد دانشکده منابع طبیعی، دانشگاه علوم کشاورزی و منابع طبیعی ساری

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...

Journal: :international journal of reproductive biomedicine 0
iraj rashidi mansoureh movahedin taki tiraihi

background: pentoxifylline (px) prevents camp breakdown by inhibiting the activity of the camp-phosphatase and presumably, stimulates sperm motion. incubation with px causes hyperactivation of sperm, an important step in achieving fertilization, and leads to changes in membranes associated with sperm capacitation. objective: the purpose of this study was to examine the effects of pentoxifylline...

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...

Journal: :مرتع و آبخیزداری 0
فرهاد آقاجانلو عضو هیأت علمی، مرکز تحقیقات کشاورزی و منابع طبیعی زنجان، ایران مرتضی اکبرزاده استادیار موسسه تحقیقات جنگل ها و مراتع کشور، ایران احمد موسوی عضو هیأت علمی، مرکز تحقیقات کشاورزی و منابع طبیعی زنجان، ایران

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 ...

2013
Hillary S Young Douglas J McCauley Kristofer M Helgen Jacob R Goheen Erik Otárola-Castillo Todd M Palmer Robert M Pringle Truman P Young Rodolfo Dirzo

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...

M. Akbarzade M.T. Gaemi Sh. Abedi

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...

Journal: :Proceedings. Biological sciences 2015
Angela A Camargo-Sanabria Eduardo Mendoza Roger Guevara Miguel Martínez-Ramos Rodolfo Dirzo

It has been suggested that tropical defaunation may unleash community-wide cascading effects, leading to reductions in plant diversity. However, experimental evidence establishing cause-effect relationships thereof is poor. Through a 5 year exclosure experiment, we tested the hypothesis that mammalian defaunation affects tree seedling/sapling community dynamics leading to reductions in understo...

2002
Catherine A. Gehring Julie E. Wolf Tad C. Theimer

Catherine A. Gehring,* Julie E. Wolf and Tad C. Theimer Department of Biological Sciences, Northern Arizona University, Flagstaff, AZ 860115640, USA Research School of Biological Sciences, Australian National University, Canberra, ACT 0200, Australia *Correspondence: E-mail: catherine.gehring@ nau.edu Abstract We examined whether terrestrial vertebrates affected the arbuscular mycorrhizal funga...

Journal: :Diversity 2023

Different species-specific traits of woody plant species, feeding preferences herbivores together with resulting effects on competition are expected to translate into different community structures and expressions biodiversity. We studied the diversity species (trees shrubs) structural forest trees, using a 30-year an 18-year dataset ungulate exclosure-control plot pairs in mixed alpine Austria...

نمودار تعداد نتایج جستجو در هر سال

با کلیک روی نمودار نتایج را به سال انتشار فیلتر کنید