نتایج جستجو برای: natural ecosystems

تعداد نتایج: 518661  

2010
Camille Lebarbenchon Chris J. Feare François Renaud Frédéric Thomas Michel Gauthier-Clerc

Understanding of ecologic factors favoring emergence and maintenance of highly pathogenic avian influenza (HPAI) viruses is limited. Although low pathogenic avian influenza viruses persist and evolve in wild populations, HPAI viruses evolve in domestic birds and cause economically serious epizootics that only occasionally infect wild populations. We propose that evolutionary ecology considerati...

2013
S. A. Quideau M. J. B. Swallow C. E. Prescott S. J. Grayston

Introduction Conclusions References

Journal: :محیط زیست طبیعی 0
آرش کرمی کارشناس ارشد رشتۀ جنگلداری و اقتصادجنگل دانشکدۀ منابع طبیعی، دانشگاه تهرا جهانگیر فقهی دانشیار گروه جنگلداری و اقتصاد جنگل دانشکدۀ منابع طبیعی، دانشگاه تهران محمدرضا مروی مهاجر استادگروه جنگلداری و اقتصاد جنگل دانشکدۀ منابع طبیعی، دانشگاه تهران

without doubt is one important aspects of sustainable forest management the continuing forest regeneration. identify and determine is effective dispersal and distribution pattern of regeneration patches in various types of forest and its evolution, in maintaining biodiversity in natural ecosystems. purpose was chosen of gorazbon district kheyrod forest for study, all patches regeneration were l...

2006
JOHN T. LITYNSKI SCOTT M. KLARA HOWARD G. MCILVRIED RAMESHWAR D. SRIVASTAVA

Increasing concentrations of CO2 and other greenhouse gases (GHG) in the Earth’s atmosphere have the potential to enhance the natural greenhouse effect, which may result in climatic changes. The main anthropogenic contributors to this increase are fossil fuel combustion, land use conversion, and soil cultivation. It is clear that overcoming the challenge of global climate change will require a ...

2013
He Chen Lekuan Ma Wei Guo Ying Yang Tong Guo Cheng Feng

Most rivers worldwide are highly regulated by anthropogenic activities through flow regulation and water pollution. Environmental flow regulation is used to reduce the effects of anthropogenic activities on aquatic ecosystems. Formulating flow alteration-ecological response relationships is a key factor in environmental flow assessment. Traditional environmental flow models are characterized by...

Journal: :Annual review of phytopathology 2002
Gregory S Gilbert

Plant pathogens cause mortality and reduce fecundity of individual plants, drive host population dynamics, and affect the structure and composition of natural plant communities. Pathogens are responsible for both numerical changes in host populations and evolutionary changes through selection for resistant genotypes. Linking such ecological and evolutionary dynamics has been the focus of a grow...

Journal: :Current opinion in microbiology 1999
G Muyzer

Five years after the introduction of denaturing gradient gel electrophoresis(DGGE) and temperature gradient gel electrophoresis (TGGE) in environmental microbiology these techniques are now routinely used in many microbiological laboratories worldwide as molecular tools to compare the diversity of microbial communities and to monitor population dynamics. Recent advances in these techniques have...

2014
Michael Manton

The term green infrastructure addresses the spatial structure of anthropogenic, seminatural and natural areas, as well as other environmental features which enable society to benefit from ecosystems’ multiple services. Focusing on two green infrastructures, anthropogenic wet meadows and natural forest successions, this thesis applies a macroecological approach based on comparisons of multiple l...

Journal: :Bulletin of the World Health Organization 1997
W J Martens R Slooff E K Jackson

Human-induced climate change threatens ecosystems and human health on a global scale. In order to withstand the worldwide threats to ecosystems, the concept of sustainable development was introduced during the 1980s. Since then, this concept has been widely applied to guide and focus policy-making. The present article reviews the health consequences of human-induced climate change on sustainabl...

2016
Scott W. Behie Bailey Bonet Vineetha M. Zacharia Dylan J. McClung Matthew F. Traxler

Actinomycetes, filamentous actinobacteria found in numerous ecosystems around the globe, produce a wide range of clinically useful natural products (NP). In natural environments, actinomycetes live in dynamic communities where environmental cues and ecological interactions likely influence NP biosynthesis. Our current understating of these cues, and the ecological roles of NP, is in its infancy...

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