نتایج جستجو برای: grazing duration of particular plant species

تعداد نتایج: 21236588  

2004
A. L. Abdel-Mawgood

Capparis decidua is a rangeland plant species growing in isolated regions in Saudi Arabia. The population in Rawdhat Khuraim was noticed to suffer from lack of new regeneration, in addition to excessive grazing which may reduce the size of the population and reduce the genetic variability. RAPD markers were used to study genetic diversity in this population and a control population. Two criteri...

2010
W. Marc Jones Lauchlan H. Fraser

Wetlands are ecologically and economically important ecosystems with high conservation value. Although wetland vegetation is strongly determined by abiotic factors, grazing disturbance may also be an important influence on this community. We evaluated the effects of livestock grazing on wetland vegetation in marsh and wet meadow zones in intermountain depressional wetlands in the southern inter...

2015
Hua Su Wei Liu Hong Xu Zongshuai Wang Huifang Zhang Haixiao Hu Yonggeng Li

The role of livestock grazing in regulating woody cover and biomass in grass-dominant systems is well recognized. However, the way in which woody plant populations in respond when livestock are removed from grazing in the absence of other disturbances, such as fire, remains unclear.We conducted a 10-year, replicated fencing experiment in a sandy semiarid rangeland in northern China (which has a...

2015
Xiliang Li Zhiying Liu Zhen Wang Xinhong Wu Xinle Li Jing Hu Hongxiao Shi Fenghui Guo Yong Zhang Xiangyang Hou

Natural grassland productivity, which is based on an individual plant's aboveground biomass (AB) and its interaction with herbivores, can obviously affect terrestrial ecosystem services and the grassland's agricultural production. As plant traits have been linked to both AB and ecosystem success, they may provide a useful approach to understand the changes in individual plants and grassland pro...

2017
Brian J. Wilsey James S. Coleman BRIAN J. WILSEY JAMES S. COLEMAN SAMUEL J. MCNAUGHTON

Three plant species from each of three grassland ecosystems were grown under elevated (700 mL/m3) and ambient (350 mL/m3) CO2 and were defoliated or left undefoliated to test whether species response to elevated CO2 and grazing is related to evolutionary grazing history or to mode of photosynthesis. The three ecosystems represented a tropical grassland dominated by C4 species (the Serengeti of ...

پایان نامه :وزارت بهداشت، درمان و آموزش پزشکی - دانشگاه علوم پزشکی و خدمات بهداشتی درمانی استان کرمانشاه 1371

background: organic nitrates relax all kinds of smooth muscle , not only vascular smooth muscle , a fact that has allowed the use of these drugs to treat many different aliments. objective.-the purpuse of this study was to examine prosepectively benefical effects , if any, of sublingual nitroglycerin on the pain of renal colic. design.- prospective , randomised , double blind, placebo- contoled...

Journal: :محیط شناسی 0
محمدحسن جوری عضو هیأت علمی، دانشگاه آزاد اسلامی واحد نور

introduction the complexity of natural ecosystem, as the rangelands, is caused to propose the different approaches toevaluatethe ecosystem on the basis of sustainable and systematic management. study on the interaction connectionsbetween plants and biotic and abiotic factors in the rangeland ecosystem can be achieved by relationsofmanagerial strategies in order to conduct the rangeland health. ...

2016
Iris Bumb Eric Garnier Denis Bastianelli Jean Richarte Laurent Bonnal Elena Kazakou

In spite of their recognized ecological value, relatively little is known about the nutritional value of species-rich rangelands for herbivores. We investigated the sources of variation in dry matter digestibility (DMD), neutral detergent fibre content (NDF) and nitrogen concentration (NC) in plants from species-rich Mediterranean rangelands in southern France, and tested whether the dry matter...

2015
Xiliang Li Zinian Wu Zhiying Liu Xiangyang Hou Warwick Badgery Huiqin Guo Qingshan Zhao Ningning Hu Junjie Duan Weibo Ren Fan Chen

Understanding the mechanism of plant morphological plasticity in response to grazing and clipping of semiarid grassland can provide insight into the process of disturbance-induced decline in grassland productivity. In recent studies there has been controversy regarding two hypotheses: 1) grazing avoidance; and 2) growth limiting mechanisms of morphological plasticity in response to defoliation....

Journal: :Ecology 2007
Jeremy D Long Rebecca S Hamilton Jocelyn L Mitchell

Species may compete indirectly by altering the traits of a shared resource. For example, herbivore-induced responses in plants may make plants more resistant or susceptible to additional herbivorous insect species. Herbivore-induced plant responses can significantly affect interspecific competition and herbivore population dynamics. These herbivore-herbivore indirect interactions have been over...

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