نتایج جستجو برای: rud rangelands also

تعداد نتایج: 2398763  

Journal: :Animal : an international journal of animal bioscience 2014
F Accatino R Sabatier C De Michele D Ward K Wiegand K M Meyer

Rangelands provide the main forage resource for livestock in many parts of the world, but maintaining long-term productivity and providing sufficient income for the rancher remains a challenge. One key issue is to maintain the rangeland in conditions where the rancher has the greatest possibility to adapt his/her management choices to a highly fluctuating and uncertain environment. In this stud...

2015
Penelope J. Mograbi Barend F. N. Erasmus E. T. F. Witkowski Gregory P. Asner Konrad J. Wessels Renaud Mathieu David E. Knapp Roberta E. Martin Russell Main

Woody biomass dynamics are an expression of ecosystem function, yet biomass estimates do not provide information on the spatial distribution of woody vegetation within the vertical vegetation subcanopy. We demonstrate the ability of airborne light detection and ranging (LiDAR) to measure aboveground biomass and subcanopy structure, as an explanatory tool to unravel vegetation dynamics in struct...

2015
Michael Elias Oliver Hensel Uwe Richter Christian Hülsebusch

Conversion of rangelands into cultivated land is one of the main challenges affecting the management of rangelands in Ethiopia. In order to inform policy makers about trends in land-use conversion, this study examined the drivers, trends, and impacts of land conversions in five locations selected in the Borana rangelands of Southern Ethiopia. This study integrated survey interviews from agro-pa...

Journal: :caspian journal of enviromental sciences 0

rangelands renewable resources play a very important role in ecosystem regulating, preserving plant genetic reservoirs, water cycle as well as providing large parts of forage requirements. these resources were considered to be a basis for sustainable development and also a basic platform for various economic activities. during the recent years in iran, these valuable sources were subjected to s...

2001
P. Bergveld

An unportant design rule for a hearmg rud 1s the reqmrement of a large stgnal to nome ratlo, wluch IS mainly determmed by that of the mIcrophone and 1t.s preampldier It ~11 be shown that m order to increase the signal to noise ratlo it IS favourable to mtegrate the preamplifier wth the rmcrophone, whtch unphes that the mIcrophone should be made of dicon, preferably with a smgle wafer technology...

2016
Joseph O. Ogutu Hans-Peter Piepho Mohamed Y. Said Gordon O. Ojwang Lucy W. Njino Shem C. Kifugo Patrick W. Wargute

There is growing evidence of escalating wildlife losses worldwide. Extreme wildlife losses have recently been documented for large parts of Africa, including western, Central and Eastern Africa. Here, we report extreme declines in wildlife and contemporaneous increase in livestock numbers in Kenya rangelands between 1977 and 2016. Our analysis uses systematic aerial monitoring survey data colle...

2004
Ani Guerdjikova

I am indebted to my advisor Juergen Eichberger for his helpful guidance and to Alexander Zimper for his helpful suggestions and illuminating discussions. I would like to thank Hans Haller, Clemens Puppe, Itzhak Gilboa, Hans Gersbach, Klaus Ritzberger, as well as the participants of the RUD conference in Evanston, of the FUR XI conference in Paris and of the PhD seminar at the University of Heid...

2017
Kenneth P. Vogel H. J. Gorz Francis A. Haskins

In the central Great Plains, pastures and rangelands often are not economically competitive with grain crops. This has led to increases in acreages of row crops at the expense of rangelands, pastures, and hay crops on marginal lands resulting in severe erosion problems. The productivity of forages, pastures, and rangelands needs to be increased to levels that would make them economically compet...

Journal: :caspian journal of environmental sciences 2014
m. pourafrasyabi z. ramezanpour

phytoplanktons are the first bio- indicators of pollution in aquatic ecosystems. phytoplankton assemblage and aquatic ecosystems are always influenced by environmental factors therefore these environmental changes and threats must be understood in any ecosystem. phytoplankton are inexpensive and readily available bio- indicators. in the present study, phytoplankton were used to study the sefid ...

Journal: :Proceedings of the National Academy of Sciences of the United States of America 2014
José D Anadón Osvaldo E Sala B L Turner Elena M Bennett

A large fraction of the world grasslands and savannas are undergoing a rapid shift from herbaceous to woody-plant dominance. This land-cover change is expected to lead to a loss in livestock production (LP), but the impacts of woody-plant encroachment on this crucial ecosystem service have not been assessed. We evaluate how tree cover (TC) has affected LP at large spatial scales in rangelands o...

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