نتایج جستجو برای: range land

تعداد نتایج: 776847  

Journal: :تحقیقات آب و خاک ایران 0
جلیل کاکه دانشجوی کارشناسی ارشد گروه علوم خاک پردیس کشاورزی و منابع طبیعی دانشگاه تهران منوچهر گرجی دانشیار گروه علوم خاک پردیس کشاورزی و منابع طبیعی دانشگاه تهران علی طویلی دانشیار دانشکدة منابع طبیعی پردیس کشاورزی و منابع طبیعی دانشگاه تهران محمد سهرابی استادیار گروه بیوتکنولوژی سازمان پژوهش های علمی و صنعتی ایران احمدعلی پوربابایی استادیار گروه علوم خاک پردیس کشاورزی و منابع طبیعی دانشگاه تهران

biological soil crusts (bscs) result from an intimate association between soil particles and cyanobacteria, algae, fungi, lichens and mosses in different proportions which live on the surface, or immediately in the uppermost millimeters of soil. therefore bscs cover the ground surface as a coherent layer, and influence primary processes such as carbon and nitrogen fixation and hydrologic status...

1999
Sybil M. Anderson Tae Jun Park Daniel Neuhauser

Recently we presented a method for modeling a quantum system to a bath that explicitly correlates the system with the individual bath modes. We do this through representation of the bath by locally propagating Gaussians (LPG), which change in position and momentum but remain Gaussian in form. The explicit correlation of the system to the bath modes enters through the simultaneous use of a di†er...

2003
K. P. Dowker Z. F. Ghassemlooy

The ambient index and temperature effects on the spectral profiles of two sets of long period gratings (LPGs) of different periods were investigated. The shorter period LPGs were found to be more sensitive than the longer period LPGs over identical ambient index ranges but less sensitive over identical temperature ranges. The coupling wavelength shifts due to temperature are also seen to be lin...

1995
Jerome K. Vanclay

A model is proposed that will allow forest and land use policy options to be explored in a repeatable, objective and quantitative way. Construction and use of the model should lead to a better understanding of spatial and temporal land use patterns. It will provide detailed spatially-explicit data on a range of parameters to enable rigorous testing and offer insights for further development. Th...

Journal: :Journal of environmental management 2014
Vincent Upton Cathal O'Donoghue Mary Ryan

Land use change is fundamentally a product of the interaction of physical land characteristics, economic considerations and agricultural and environmental policies. Researchers are increasingly combining physical and socio-economic spatial data to investigate the drivers of land-use change in relation to policy and economic developments. Focusing on Ireland, this study develops a panel data set...

2010
Bethany A. Bradley B. A. Bradley

Global change poses significant challenges for ecosystem conservation. At regional scales, climate change may lead to extensive shifts in species distributions and widespread extirpations or extinctions. At landscape scales, land use and invasive species disrupt ecosystem function and reduce species richness. However, a lack of spatially explicit models of risk to ecosystems makes it difficult ...

2015
Tânia Barros João Carvalho Maria João Ramos Pereira Joaquim P. Ferreira Carlos Fonseca Lucas C. R. Silva

Species range-limits are influenced by a combination of several factors. In our study we aimed to unveil the drivers underlying the expansion of the Egyptian mongoose in Portugal, a carnivore that was confined to southern Portugal and largely increased its range during the last three decades. We evaluated the expansion of the species in three periods (1980-1990, 1990-2000 and 2000-2010), by pro...

2014
Risto K. Heikkinen Greta Bocedi Mikko Kuussaari Janne Heliölä Niko Leikola Juha Pöyry Justin M. J. Travis Francesco de Bello

Dynamic models for range expansion provide a promising tool for assessing species' capacity to respond to climate change by shifting their ranges to new areas. However, these models include a number of uncertainties which may affect how successfully they can be applied to climate change oriented conservation planning. We used RangeShifter, a novel dynamic and individual-based modelling platform...

1995
Jerome K. Vanclay

A model is proposed that will enable forest and land use policy options to be explored in an repeatable, objective and quantitative way. Construction and use of the model should lead to a better understanding of spatial and temporal land use patterns. It will provide detailed spatially-explicit data on a range of parameters to enable on-going development and validation. The model is based on th...

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