نتایج جستجو برای: natural landscapes

تعداد نتایج: 499527  

Journal: :محیط شناسی 0
اطهره نژادی مجید مخدوم سید مسعود منوری علی بالی حمید فراهانی راد

human activities often adversely affect natural landscapes and ecosystems. natural landscapes consist of habitats, and habitat loss and fragmentation are major threats to biodiversity. environmental impact assessment (eia)as a systematic and well documented procedure to identify, describe and assess the direct and indirect effects of a developmental project in different environments does not co...

2014
Klaus Jaffe

Do different fields of knowledge require different research strategies? A numerical model exploring different virtual knowledge landscapes, revealed two diverging optimal search strategies. Trend following is maximized when the popularity of new discoveries determine the number of individuals researching it. This strategy works best when many researchers explore few large areas of knowledge. In...

2015
Debissa Lemessa Peter A. Hambäck Kristoffer Hylander

Bird and arthropod predation is often associated with natural pest control in agricultural landscapes, but the rates of predation may vary with the amount of tree cover or other environmental factors. We examined bird and arthropod predation in three tree-rich and three tree-poor landscapes across southwestern Ethiopia. Within each landscape we selected three tree-rich and three tree-poor homeg...

Journal: :محیط زیست طبیعی 0
سپیده سعیدی دانشجوی دکتری ارزیابی و آمایش محیط ‏زیست، دانشگاه علوم کشاورزی و منابع طبیعی گرگان، ایران مرجان محمدزاده استادیار دانشگاه علوم کشاورزی و منابع طبیعی گرگان، ایران عبدالرسول سلمان ماهینی دانشیار دانشگاه علوم کشاورزی و منابع طبیعی گرگان، ایران سید حامد میرکریمی استادیار دانشگاه علوم کشاورزی و منابع طبیعی گرگان، ایران

recent literature attaches high importance to scenic evaluation of natural landscapes. scenic beauty evaluation techniques often use parameters derived from photographs or collected in situ data via field assessment and questionnaires. such techniques are relatively costly and time consuming. park managers and recreational planners require spatial tools and techniques that are fast, flexible an...

2017
Tyler G Creech Clinton W Epps Erin L Landguth John D Wehausen Rachel S Crowhurst Brandon Holton Ryan J Monello

Landscape genetic studies based on neutral genetic markers have contributed to our understanding of the influence of landscape composition and configuration on gene flow and genetic variation. However, the potential for species to adapt to changing landscapes will depend on how natural selection influences adaptive genetic variation. We demonstrate how landscape resistance models can be combine...

2000
JOHN F. TOOKER LAWRENCE M. HANKS

Pine needle scale, Chionaspis pinifoliae (Fitch), is a pest of many species of conifers in urban habitats and Christmas tree farms. We found that the scale was abundant in impoverished habitats, such as ornamental landscapes, and scarce in more natural, park-like habitats. Rates of parasitism were highest in impoverished habitats, suggesting that parasitoids were not effective in suppressing sc...

Journal: :space ontology international journal 2015
mehdi khakzand mohsen faizi abbas azari

by considering certain factors like those mentioned by ian thompson (2005) in his definition of landscape, i.e. ecology, community and delight, in designing landscapes, one can find the vocation more applicable and useful. city rivers can play a very important role with regard to such values. in fact, the presence of nature and wildlife could not only be the lifeline of a city, but also a facto...

The importance of the economic aspect of tourism usually overshadow many natural tourism destinations. Fereydounshahr county in Isfahan province, with pristine mountainous landscapes and diverse natural features, has high potential to attract many tourists. However, pristineness over much of its area suggests limiting the public access based on the degree of naturalness. Hence, the aim of this ...

Journal: :Current Biology 2015
David P. Edwards James J. Gilroy Gavin H. Thomas Claudia A. Medina Uribe Torbjørn Haugaasen

The conversion of natural habitats to farmland is a major driver of the global extinction crisis. Two strategies are promoted to mitigate the impacts of agricultural expansion on biodiversity: land sharing integrates wildlife-friendly habitats within farmland landscapes, and land sparing intensifies farming to allow the offset of natural reserves. A key question is which strategy would protect ...

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