نتایج جستجو برای: rangeland ecosystem

تعداد نتایج: 85678  

1- INTRODUCTION Over the past few decades, the objective of the evaluation and monitoring of the optimal utilization of sustainable natural resource services and ecosystem performance has been the successor to the ecosystem structure. Tongway and Hindley introduced a Landscape Function Analysis (LFA) method in 2004 to evaluate the ecosystem Function. In the new method, soil is considered as th...

Journal: :مرتع و آبخیزداری 0
منصوره کارگر دانشجوی دکتری علوم مرتع، دانشکده منابع طبیعی، دانشگاه علوم کشاورزی و منابع طبیعی ساری، ایران زینب جعفریان دانشیار دانشکده منابع طبیعی، دانشگاه علوم کشاورزی و منابع طبیعی ساری، ایران محدثه احسانی دانشجوی دکتری علوم مرتع، دانشگاه علوم کشاورزی و منابع طبیعی گرگان، ایران.

for the scientific and accurate management of rangeland ecosystems, having information about ecosystem as indicators of ecosystem health and function is needed. the aim of this research is to study the effects of grazing on soil surface indicators and rangeland functional properties by using landscape functional analysis (lfa) method. for this purpose, the present study was conducted in two reg...

2004
E. RAYMOND JACE T. FAHNESTOCK JEFFREY M. WELKER

WILLIAM A. REINERS Department of Botany University of Wyoming PO Box 3165 Laramie, Wyoming 82071-3165, USA ABSTRACT / Carbon sequestration was estimated a northern mixed-grass prairie site and a sagebrush–steppe site in southeastern Wyoming using an approach that integrates remote sensing, CO2 flux measurements, and meteorological data. Net ecosystem exchange (NEE) of CO2 was measured using air...

Dina Askarizadeh Mohammad Hassan Jouri, Mohammad Mahdavi, Vahid Rahimi

Mountainous rangeland ecosystems have a highly delicate position in ecologic areabecause of severe environmental conditions and having wildlife and livestock. Knowing andrealizing the biotic and abiotic components, which have an interaction with each other in thisecosystem, perform the most important role in to desirable management of it. The systematicmanagement is one of the managing features...

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...

2005

Humans have exerted large-scale changes on the terrestrial biosphere, primarily through agriculture; however, the impacts of such changes on the hydrologic cycle are poorly understood. The purpose of this study was to test the hypothesis that the conversion of natural rangeland ecosystems to agricultural ecosystems impacts the subsurface portion of the hydrologic cycle by changing groundwater r...

Journal: :Environmental science & technology 2007
Edward P Kolodziej David L Sedlak

Cattle and other livestock excrete endogenous steroid hormones, including estrogens, androgens, and progestins; therefore, allowing grazing livestock direct access to surface waters can result in the release of steroids in agricultural watersheds. Elevated concentrations of steroids are problematic because low concentrations of certain steroids can affect fish reproduction. To assess the occurr...

2017
Christopher Potter Steven Klooster Seth Hiatt Matthew Fladeland Vanessa Genovese Peggy Gross

Afforestation of marginal agricultural lands represents a promising option for carbon sequestration in terrestrial ecosystems. An ecosystem carbon model was used to generate new national maps of annual net primary production (NPP), one each for continuous land covers of ‘forest’, ‘crop’, and ‘rangeland’ over the entire U. S. continental area. Direct inputs of satellite “greenness” data from the...

Journal: :Ecological applications : a publication of the Ecological Society of America 2011
Jason P Field David D Breshears Jeffrey J Whicker Chris B Zou

Rangelands are globally extensive, provide fundamental ecosystem services, and are tightly coupled human-ecological systems. Rangeland sustainability depends largely on the implementation and utilization of various grazing and burning practices optimized to protect against soil erosion and transport. In many cases, however, land management practices lead to increased soil erosion and sediment f...

Land use change as the most important destructive factor in natural ecosystems is a globally problem that changes soil properties. Therefore, correct management and recognition of change aspects on each component of the ecosystem is necessary. This process causes land destruction, ecosystem instability, soil erosion, and more biological threats. Due to increasing land use conversion from rangel...

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