نتایج جستجو برای: species composition

تعداد نتایج: 776958  

2008
J. - C. SvENNiNG D. A. KiNNER R. F. STALLARD B. M. J. ENGELBRECHT S. J. WRIGHT

The ecological mechanisms hypothesized to structure species-rich communities range from strict local determinism to neutral ecological drift. We assessed the degree of ecological determinism in tropical plant community structure by analyses of published demographic data; a broad range of spatial, historical, and environmental variables; and the distributions of 33 herbaceous species (plot size ...

بصیری, مهدی , خواجه الدین, سیدحمال الدین , وهابی, محمد رضا ,

Short-term changes (5 years) in canopy cover, species composition and forage production were studied under protection from grazing and grazed condition in 19 range sites in Fereydan region, Isfahan province. In this study, density, canopy cover and forage production data were obtained from quadrates inside and outside exclosures in the spring of 1983. These parameters were studied again in 1988...

Journal: :Ecology 2008
David A Rogers Thomas P Rooney Daniel Olson Donald M Waller

We resurveyed the under- and overstory species composition of 94 upland forest stands in southern Wisconsin in 2002-2004 to assess shifts in canopy and understory richness, composition, and heterogeneity relative to the original surveys in 1949-1950. The canopy has shifted from mostly oaks (Quercus spp.) toward more mesic and shade-tolerant trees (primarily Acer spp.). Oak-dominated early-succe...

2014
Rafi Kent Avi Bar-Massada Yohay Carmel

Global patters of species distributions and their underlying mechanisms are a major question in ecology, and the need for multi-scale analyses has been recognized. Previous studies recognized climate, topography, habitat heterogeneity and disturbance as important variables affecting such patterns. Here we report on analyses of species composition - environment relationships among different taxo...

Journal: :Ecology 2007
J S Kominoski C M Pringle B A Ball M A Bradford D C Coleman D B Hall M D Hunter

Since species loss is predicted to be nonrandom, it is important to understand the manner in which those species that we anticipate losing interact with other species to affect ecosystem function. We tested whether litter species diversity, measured as richness and composition, affects breakdown dynamics in a detritus-based stream. Using full-factorial analyses of single- and mixed-species leaf...

Journal: :The Journal of Cell Biology 1999
Roger Schneiter Britta Brügger Roger Sandhoff Günther Zellnig Andrea Leber Manfred Lampl Karin Athenstaedt Claudia Hrastnik Sandra Eder Günther Daum Fritz Paltauf Felix T. Wieland Sepp D. Kohlwein

Nano-electrospray ionization tandem mass spectrometry (nano-ESI-MS/MS) was employed to determine qualitative differences in the lipid molecular species composition of a comprehensive set of organellar membranes, isolated from a single culture of Saccharomyces cerevisiae cells. Remarkable differences in the acyl chain composition of biosynthetically related phospholipid classes were observed. Ac...

Journal: :iranian chemical communication 2014
hassan valizadeh fatemeh mahmoodi kordi reza koohkan mir babak bahadori mehdi moridi farimani

lycium species is a popular medicinal plant in the traditional chinese medicine and lycium ruthenicum is a native medicinal plant of iran. lycium genus has several biologically important properties too. investigation of chemical composition of ethyl acetate extract of this plant is the goal of this study. two coumarins (scopoletin and sculetin) and methyl-2-hydroxy-4-undecanoxy-trans-cinamate w...

Journal: :دانش گیاه پزشکی ایران 0
حامد غباری دانشجوی سابق دکتری حشره شناسی پردیس کشاورزی و منابع طبیعی دانشگاه تهران و استادیار دانشگاه شهر جاماسب نوذری استادیار، پردیس کشاورزی و منابع طبیعی دانشگاه تهران حسین الهیاری دانشیار، پردیس کشاورزی و منابع طبیعی دانشگاه تهران مارک کالاشیان استاد انستیتوی جانورشناسی ارمنستان

buprestid beetles are one of the important components of the biodiversity of forest ecosystem in kurdistan province. different characteristics of biodiversity of buprestid beetles were studied by use of window trap, colored pan and colored sticky trap in these forests during 2009 and 2010. a total of 1205 specimens of 44 species were caught by use of considered traps during appearance of adults...

Forest fragmentation results in a loss of forest interior and an increase in edge habitat. We studied how understorey bird community composition and habitat variables changed along an edge-to-interior gradient in a 1248-ha lowland rainforest patch in peninsular Malaysia. Birds and environmental variables such as vegetation structure and litter depth were detected within a 25-m radius of each of...

Journal: :Ecological Informatics 2010
Zhihua Mao Venetia Stuart Delu Pan Jianyu Chen Fang Gong Haiqing Huang Qiankun Zhu

In most cases authors are permitted to post their version of the article (e.g. in Word or Tex form) to their personal website or institutional repository. Authors requiring further information regarding Elsevier's archiving and manuscript policies are encouraged to visit: a b s t r a c t a r t i c l e i n f o Understanding the spectral characteristics of remotely-sensed reflectance by different...

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