نتایج جستجو برای: spatial variation

تعداد نتایج: 634391  

2014
Matthew P. Hammond Jurek Kolasa

Ecological processes, like the rise and fall of populations, leave an imprint of their dynamics as a pattern in space. Mining this spatial record for insight into temporal change underlies many applications, including using spatial snapshots to infer trends in communities, rates of species spread across boundaries, likelihood of chaotic dynamics, and proximity to regime shifts. However, these a...

Journal: :Philosophical transactions of the Royal Society of London. Series B, Biological sciences 2014
Michael D Madritch Clayton C Kingdon Aditya Singh Karen E Mock Richard L Lindroth Philip A Townsend

Fine-scale biodiversity is increasingly recognized as important to ecosystem-level processes. Remote sensing technologies have great potential to estimate both biodiversity and ecosystem function over large spatial scales. Here, we demonstrate the capacity of imaging spectroscopy to discriminate among genotypes of Populus tremuloides (trembling aspen), one of the most genetically diverse and wi...

Journal: :The Journal of neuroscience : the official journal of the Society for Neuroscience 1992
C E Connor K O Johnson

A previous study showed that roughness perception may depend on either temporal or spatial variations in firing rate among cutaneous mechanoreceptive afferents. The present study was designed to distinguish between these hypotheses. Plastic surfaces embossed with patterns of dots designed to produce predictable alterations in temporal and spatial firing rate variation were used as stimuli in ps...

Journal: :desert 2010
s. modallaldoust

a watershed management program is usually based on the results of watershed modeling. accurate modeling results are decided by the appropriate parameters and input data. precipitation is the most important input for watershed modeling. precipitation characteristics usually exhibit significant spatial variation, even within small watersheds. therefore, properly describing the spatial variation o...

Journal: :international journal of environmental research 2013
w. huang s. yano j.m. zhang y.r. wang

the environmental and ecological issues in the flow-reduced river reach are very serious and arereceiving increasingly attention. in this study, we investigate the temporal and spatial changes in δ13c and δ15n of periphyton and isotopic relationship between periphyton and the endangered fish (ayu, plecoglossusaltivelis) in a flow-reduced river reach in japan. much of the spatial and temporal va...

2006
A. Marm Kilpatrick William A. Mitchell Warren P. Porter David J. Currie

Hypothesis: Spatial variation in species richness is caused by increased maintenance metabolic costs that increase habitat overlap and decrease species richness. Organisms: Non-volant mammals in North America. Results: The latitudinal gradient in species richness could be completely explained by variation in maintenance metabolic costs. Additional spatial variation in species richness was posit...

Journal: :environmental health engineering and management 0
zabihollah yousefi department of environmental health engineering, school of public health, mazandaran university of medical sciences, sari, iran reza ali mohammadpour tahmtan department of biostatistics, school of public health, mazandaran university of medical sciences, sari, iran farzad kazemi department of environmental health engineering, school of public health, mazandaran university of medical sciences, sari, iran

background: in recent times, the decreasing groundwater reserves due to over-consumption of water resources and the unprecedented reduction of precipitation, during the past 1 decades, have resulted in a change in the volume and quality of water with time. the aim of this study was to determine the spatial and temporal variations of hardness and total dissolved solids in drinking water resource...

The disparate spatial and temporal distribution of rainfall in the country and climate variation sometimes leads to rivers flooding and large flood events, which are remarkable for life and financial losses. Flood control design requires accurate knowledge of the flood generator basin, especially smaller ones, in large basins. Determining the potential of flood generation to specify the...

Journal: :تحقیقات جغرافیایی 0
حسین عساکره زهره سیفی پور گروه جغرافیای دانشگاه زنجان

due to deep, complex and everlasting interaction between precipitation and climatic elements-factors, there are changes and varieties in both time and space dimensions. so that climate experts and related scientists take their attentions to this phenomenon. an approach to do this kind of investigations is to describe spatial variations based on spatial statistics. in this paper the main object ...

2012
Ronei Baldissera Everton N. L. Rodrigues Sandra M. Hartz

The distribution of beta diversity is shaped by factors linked to environmental and spatial control. The relative importance of both processes in structuring spider metacommunities has not yet been investigated in the Atlantic Forest. The variance explained by purely environmental, spatially structured environmental, and purely spatial components was compared for a metacommunity of web spiders....

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