نتایج جستجو برای: trophic evaluation

تعداد نتایج: 839178  

Journal: :Proceedings of the National Academy of Sciences of the United States of America 2016
Jens-Christian Svenning Pil B M Pedersen C Josh Donlan Rasmus Ejrnæs Søren Faurby Mauro Galetti Dennis M Hansen Brody Sandel Christopher J Sandom John W Terborgh Frans W M Vera

Trophic rewilding is an ecological restoration strategy that uses species introductions to restore top-down trophic interactions and associated trophic cascades to promote self-regulating biodiverse ecosystems. Given the importance of large animals in trophic cascades and their widespread losses and resulting trophic downgrading, it often focuses on restoring functional megafaunas. Trophic rewi...

Journal: :Proceedings. Biological sciences 2016
Dirk Sanders Andrea Moser Jason Newton F J Frank van Veen

Trophic assimilation efficiency (conversion of resource biomass into consumer biomass) is thought to be a limiting factor for food chain length in natural communities. In host-parasitoid systems, which account for the majority of terrestrial consumer interactions, a high trophic assimilation efficiency may be expected at higher trophic levels because of the close match of resource composition o...

پایان نامه :دانشگاه تربیت معلم - سبزوار - دانشکده ادبیات و علوم انسانی 1391

abstract this study evaluates the iranian pre-university english textbook in terms of needs, objectives, content, and methodology. the study was designed on the qualitative- quantitative survey basis using interviews and questionnaires, a researcher-made textbook evaluation checklist and a needs analysis questionnaire. the textbook evaluation questionnaire was used in this study to elicit the ...

2002
Rainer Froese Stefan Garthe Uwe Piatkowski Daniel Pauly

We compared several large marine ecosystems in terms of species numbers of fishes, sea birds, marine mammals, and cephalopods. We examined how these numbers were distributed by trophic level, from herbivores to top predators. We created group-specific trophic signatures as plots of number of species by trophic level, and used these to identify similarities and discrepancies between taxonomic gr...

Journal: :Revista de biologia tropical 2011
Camilo B García Cristian Camilo Contreras

Ecological studies on commercial important fish species are of great value to support resource management issues. This study calculated trophic levels of those Colombian Caribbean fish species whose diet has been locally described. Usable diet data of 119 species resulted in 164 trophic level estimates. An ordinary regression model relating trophic level and fish size was formulated. The regres...

2013
Paul Woodcock David P. Edwards Rob J. Newton Chey Vun Khen Simon H. Bottrell Keith C. Hamer

Trophic organisation defines the flow of energy through ecosystems and is a key component of community structure. Widespread and intensifying anthropogenic disturbance threatens to disrupt trophic organisation by altering species composition and relative abundances and by driving shifts in the trophic ecology of species that persist in disturbed ecosystems. We examined how intensive disturbance...

2017
Shawn A Steffan Yoshito Chikaraishi Prarthana S Dharampal Jonathan N Pauli Christelle Guédot Naohiko Ohkouchi

Detritivory is the dominant trophic paradigm in most terrestrial, aquatic, and marine ecosystems, yet accurate measurement of consumer trophic position within detrital (="brown") food webs has remained unresolved. Measurement of detritivore trophic position is complicated by the fact that detritus is suffused with microbes, creating a detrital complex of living and nonliving biomass. Given that...

Journal: :international journal of environmental research 2011
r. ahmadi f. mohebbi p. hagigi l. esmailly r. salmanzadeh

this research summarizes the data on benthic macro invertebrates collected from 25 points in the urmia lake wetlands during november 2008 to february 2009. the purpose of the study was to assess the effects of elevated salinity and nutrient (nitrogen and phosphorus) levels on macro invertebrate abundance and composition. a total of 32 taxa were collected, and the common taxa, including chirono...

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