نتایج جستجو برای: khabr rangelands

تعداد نتایج: 2388  

2013
Nathan F Sayre Ryan RJ McAllister Brandon T Bestelmeyer Mark Moritz Matthew D Turner

www.frontiersinecology.org © The Ecological Society of America R – including grasslands, shrublands, savannas, deserts, prairies, steppe, and tundra – comprise 30–40% of Earth’s ice-free terrestrial surface (depending on one’s definition and data sources; Asner et al. 2004) and account for 91% of the world’s grazing lands (Reid et al. 2008). Encompassing watersheds for vast downstream populatio...

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...

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...

2012
A. Jamalian M. Shams-Ghahfarokhi A. Amani

Department of Mycology, Pasteur Institute of Iran, 13164 Tehran, Iran Department of Biology, Islamic Azad University, Science and Research Branch, Tehran, Iran Department of Mycology, Faculty of Medical Sciences, Tarbiat Modares University, 14115-331 Tehran, Iran Department of Medicinal Plants and By-Products, Research Institute of Forest and Rangelands, 13185 Tehran, Iran Medicinal Chemistry L...

2017
Greg R. Guerin Ben Sparrow Andrew Tokmakoff Anita Smyth Emrys Leitch Zdravko Baruch Andrew J. Lowe

Australian rangelands ecosystems cover 81% of the continent but are understudied and continental-scale research has been limited in part by a lack of precise data that are standardised between jurisdictions. We present a new dataset from AusPlots Rangelands that enables integrative rangelands analysis due to its geographic scope and standardised methodology. The method provides data on vegetati...

Journal: :Environmental management 2011
Dustin D Johnson Kirk W Davies Peter T Schreder Anna-Marie Chamberlain

Medusahead (Taeniatherum caput-medusae (L.) Nevski) is an exotic annual grass invading rangelands in the western United States. Medusahead is a serious management concern because it decreases biodiversity, reduces livestock forage production, and degrades the ecological function of rangelands. Despite the obvious importance of ranchers as partners in preventing and managing medusahead in rangel...

2016
Teshome Abate Ayana Angassa

INTRODUCTION Analyzing trends of land use systems and the changes occurred overtime is an effective way of assessing the impacts of land use/land cover (LULC) changes on ecosystem function. It provides important insights for understanding the spatial patterns of land use processes. The rangelands of southern Ethiopia are adversely affected by increased human population pressure, encroachment of...

2010

For most ecosystems, net ecosystem exchange of CO2 (NEE) varies within and among years in response to environmental change. We analyzed measurements of CO2 exchange from eight native rangeland ecosystems in the western United States (58 site-years of data) in order to determine the contributions of photosynthetic and respiratory (physiological) components of CO2 exchange to environmentally caus...

2013
Navinder J Singh Yash Veer Bhatnagar Nicolas Lecomte Joseph L Fox Nigel G Yoccoz

Nomadic pastoralism has thrived in Asia’s rangelands for several millennia by tracking seasonal changes in forage productivity and coping with a harsh climate. This pastoralist lifestyle, however, has come under intense transformations in recent decades due to socio-political and land use changes. One example is of the high-altitude trans-Himalayan rangelands of the Jammu and Kashmir State in n...

2017
R. Dave Evans Richard A. Gill Valerie T. Eviner

Soil characteristics and functions are critical determinants of rangeland systems and the ecosystem services that they provide. Rangeland soils are extremely diverse, but an emerging understanding is that paradigms developed in more mesic forest ecosystems may not be applicable. Vascular plants, biological soil crusts, and the soil microbial community are the three major functional groups of or...

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