نتایج جستجو برای: because of overgrazing

تعداد نتایج: 21165699  

1999
Craig Roberts

warm-season bunch grass native to the eastern United States and is still often found east of Kansas and Oklahoma. This highly productive grass is best adapted to wet habitats; and remnant colonies are commonly found in flood plains and along stream banks. Eastern gamagrass is a relative of field corn (Zea mays) and is characterized by numerous short, well-developed rhizomes. Lower culm internod...

2015
Dongli Wan Yongqing Wan Xiangyang Hou Weibo Ren Yong Ding Rula Sa

BACKGROUND Stipa grandis (Poaceae) is one of the dominant species in a typical steppe of the Inner Mongolian Plateau. However, primarily due to heavy grazing, the grasslands have become seriously degraded, and S. grandis has developed a special growth-inhibition phenotype against the stressful habitat. Because of the lack of transcriptomic and genomic information, the understanding of the molec...

Journal: :desert 2008
t. shamekhi h. mohammadi kangarani j. l. blanchez

desertification of the arid and semi-arid lands of the world has been proceeding for more than a thousand years.human-induced degradation in these areas is regularly cited as one of the principal causes of desertification.euphrates and tigris basin as the case study of this research in some aspects is almost unique in the world. but thisbasin has been confronted to progressive desertification. ...

Journal: Desert 2017
D. Hoffmeister F. Khormali, J. Mohammadi M. Bagheri Bodaghabadi M. Kehl S. Maleki

The effects of geological conditionwere assessed on density of Soil Organic Carbon (SOC) and Nitrogen (N)in a sequence of hillslope landscape, derived from different lithology i.e. loess deposit, reworked loess, marl with mixed siltstone and shale, reddish brown clay deposits and older loess in the semiarid area of northern Iran. However, other factors can influence SOC and N density such as la...

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه شاهد - دانشکده علوم پایه 1388

introduction acetic acid bacteria are large group of obligate aerobic gram negative bacteria with the ability to oxidize ethanol to acetic acid (1). they are widely distributed in natural habitats and classified in family acetobacteraceae. members of this family are useful in industrial production of vinegar(2). acetic acid bacteria (aab) can use substrates as glucose, ethanol, lactate or glyc...

2017
Josée Lefebvre Gilles Gauthier Jean-François Giroux Austin Reed Eric T. Reed Luc Bélanger

Between the early 1900s and the 1990s, the greater snow goose Anser caerulescens atlanticus population grew from 3000 individuals to more than 700 000. Because of concerns about Arctic degradation of natural habitats through overgrazing, a working group recommended the stabilization of the population. Declared overabundant in 1998, special management actions were then implemented in Canada and ...

2015
Xiang Yao Michael J. Christensen Gensheng Bao Chunping Zhang Xiuzhang Li Chunjie Li Zhibiao Nan

Overgrazing of China's grasslands is increasingly causing biodiversity to decline. In degenerated grasslands of northwest China endophyte (Epichloё gansuensis) infected Achnatherum inebrians (drunken horse grass) is becoming widely distributed because of its toxicity to livestock. In this study, we investigated the ecological consequences of endophyte toxicity in this native grass, at three sit...

2005
Betty Collis Anoush Margaryan

Business needs in many corporations call for learning outcomes that involve problem solutions, and creating and sharing new knowledge within workplace situations that may involve collaboration among members of a team. We argue that work-based activities (WBA) and computer-supported collaborative learning (CSCL) are appropriate components for courses in such learning situations. Via this approac...

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