نتایج جستجو برای: quantity and diversity

تعداد نتایج: 16854509  

Journal: :Proceedings of the National Academy of Sciences of the United States of America 2008
Courtney L Meier William D Bowman

Decomposition is a critical source of plant nutrients, and drives the largest flux of terrestrial C to the atmosphere. Decomposing soil organic matter typically contains litter from multiple plant species, yet we lack a mechanistic understanding of how species diversity influences decomposition processes. Here, we show that soil C and N cycling during decomposition are controlled by the composi...

2011
A. Wilby

Contents 1. Introduction – biodiversity in agricultural ecosystems 2. Planned diversity and the functioning of agricultural systems 2.1. Intraspecific diversity 2.2. Species diversity 2.3. Habitat and landscape diversity 3. Unplanned diversity and the functioning of agricultural systems. 3.1. Pollination services 3.2. Soil processes 3.3. Natural pest control 4. Conclusions Bibliography Biograph...

2012
S. J. Salter J. Hinds K. A. Gould L. Lambertsen W. P. Hanage M. Antonio P. Turner P. W. M. Hermans H. J. Bootsma K. L. O'Brien S. D. Bentley

The capsule polysaccharide locus (cps) is the site of the capsule biosynthesis gene cluster in encapsulated Streptococcus pneumoniae. A set of pneumococcal samples and non-pneumococcal streptococci from Denmark, the Gambia, the Netherlands, Thailand, the UK and the USA were sequenced at the cps locus to elucidate serologically mistyped or non-typable isolates. We identified a novel serotype 33B...

2012
Maria Rebolleda-Gomez William Ratcliff Michael Travisano

The evolution of multicellularity was one of the key innovations in the history of life on Earth. Virtually all morphological and ecological diversity in macro-organisms builds upon the evolutionary potential associated with multicellularity. We examined the potential for ecological diversity to rapidly arise following transitions to multicellularity. Replicate microcosms containing the yeast S...

2001
Marc Corbeels

The global terrestrial heterotrophic respiration is estimated at about 60 Gt C yr-1 (Schlesinger, 1991). Plant litter produced during senescence processes and plant residues left on site after harvest operations are the primary substrate for heterotrophic respiration in plant-soil ecosystems. They constitute both of aboveground and belowground plant parts. Substrate quality, together with the p...

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه علوم کشاورزی و منابع طبیعی گرگان - دانشکده مرتع و آبخیزداری و شیلات و محیط زیست 1391

مراتع حدود نیمی از خشکی های جهان را در بر دارند و پوشش گیاهی آن در نتیجه تأثیر متقابل محیط و موجودات زنده به وجود آمده است و به عنوان یک اکوسیستم طبیعی مدیریت می شوند. علاوه بر مراتع، راه ها در عصر حاضر نیز از اجزا مهم و زیرساخت های اصلی زندگی نوین و توسعه کشورها به شمار می روند. جاده ها ساخته دست بشر هستند و جوامع گیاهی کنار جاده تحت تأثیر ساخت و ساز قرار دارند. پوشش "رودرال" به مجموعه ای از پ...

2003
Demetrio Boltovskoy Nancy Correa Andrés Boltovskoy

Approximately 7000 marine zooplanktonic species have been described so far for the World Ocean; in the South Atlantic the presence of 40% of these has been confirmed, and an additional 20–30% are expected to be recorded in the future. The overall number of described species is very low when compared with other communities, and yet it may not be too far from the final, complete inventory. Very a...

Journal: :Proceedings. Biological sciences 2011
Ben Adams Alice Carolyn McHardy

Punctuated antigenic change is believed to be a key element in the evolution of influenza A; clusters of antigenically similar strains predominate worldwide for several years until an antigenically distant mutant emerges and instigates a selective sweep. It is thought that a region of East-Southeast Asia with year-round transmission acts as a source of antigenic diversity for influenza A and se...

Journal: :Frontiers in Ecology and Evolution 2021

Land use change has led to large-scale insect decline, threatening ecosystem resilience through reduced functional diversity. Even in nature reserves, losses diversity have been detected. Hereby, changes local habitat quality and landscape-scale quantity can play a role driving toward erosion. Our aim was analyze how factors simultaneously affect Therefore, we sampled moths two Italian coastal ...

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