نتایج جستجو برای: rangeland ecosystems

تعداد نتایج: 48371  

2008
Jinkai Zhang Karl Staenz Peter R. Eddy Nadia Rochdi Dave Rolfson Anne M. Smith

The goal of this research was to investigate the potential of hyperspectral Hyperion (EO-1) data to derive fractional cover of rangeland components using constrained linear spectral mixture analysis. Hyperion image data were acquired over the Antelope Creek Ranch located in southern Alberta, Canada in July 2005. These image data were first corrected for the sensor artifacts such as spatial mis-...

Rangelands are the most important ecosystem for carbon sequestration. Knowledge of plant response to grazing is one of important requirements for rangeland management. Stocking rate is one of main factors in destruction of the vegetation cover in rangeland ecosystems. Livestock grazing has the potential to substantially alter carbon storage in grassland ecosystem. This study examined the effect...

2013
Arthur J. Richardson David E. Escobar Harold W. Gausman James H. Everitt

We tested the accuracy of an atmospheric correction method that depends on clear water bodies to infer solar and atmospheric parameters for radiative transfer equations by measuring the reflectance signature of four prominent south Texas rangeland plants with the Earth Resource Technology (LANDSAT) satellite multispectral scanner (MSS) and a ground-based Exotech Model 20 spectroradiometer. The ...

2009
Clare E. Aslan Matthew B. Hufford Rebecca S. Epanchin-Niell Jeffrey D. Port Jason P. Sexton Timothy M. Waring

Private landowners are often de facto stewards of biodiversity and ecosystem services. In California’s Sierra Nevada foothills, ranchers frequently present the only defense against biological invasions in private rangelands. Although ranchers’ land management goals (e.g., the desire to control invasive species) can be consistent with ecosystem protection, practical constraints often limit their...

Journal: :Journal of environmental management 2014
David Toledo Urs P Kreuter Michael G Sorice Charles A Taylor

Risk and liability concerns regarding fire affect people's attitudes toward fire and have led to human-induced alterations of fire regimes. This has, in turn, contributed to brush encroachment and degradation of many grasslands and savannas. Efforts to successfully restore such degraded ecosystems at the landscape scale in regions of the United States with high proportions of private lands requ...

In applied studies, the investigation of the relationship between a plant species and environmental variables is essential to manage ecological problems and rangeland ecosystems. This research was conducted in summer 2016. The aim of this study was to compare the predictive power of a number of Species Distribution Models (SDMs) and to evaluate the importance of a range of environmental variabl...

2015
Nathan A. Nelson Jennifer Pierce

Rangelands are characterized by more arid climates than forested regions; therefore, establishing fire histories using traditional methods (e.g. fire-scars from trees or charcoal in lake sediments) is problematic. This study uses radiocarbon dating of charcoal preserved in alluvial fans and stream deposits to reconstruct a record of fire and geomorphic response in rangelands of southwestern Ida...

2003
TONY BANKS

— This paper contributes to the debate over land tenure in rural China by extending its spatial coverage to the country’s extensive rangeland regions. Key characteristics of pastoral tenure, identified from field appraisals in western China, include group tenure and fuzzy boundaries. Although these characteristics give rise to efficiency concerns, from a new institutional economics perspective ...

2016
Gary E. Belovsky

It has been hypothesized that some herbivores may increase the cycling of nutrients in ecosystems, thereby increasing plant production even after herbivore consumption is considered. Such herbivory could maintain the productivity of ecosystems and should not be curtailed. This contrasts with the traditional view whereby herbivory always reduces plant production. Two grasshoppers (Melanoplus san...

سلمان‌ماهینی, عبدالرسول, شیخ‌گودرزی, مهدی, علیزاده‌شعبانی, افشین, فقهی, جهانگیر,

  Urbanization is one of the most significant global changes. The rapid growth in urban area isimposing high pressure to land and their resources. With regard to various ecological services of the Hyrcanian ecosystems and the necessity to conserve them, this research aimed to investigate the growth trend of urban areas and their impacts on land suitability of the conservational patches in Korga...

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