نتایج جستجو برای: ecological factors

تعداد نتایج: 1163995  

Journal: :Proceedings. Biological sciences 2010
Marian Y L Wong

Why non-breeding subordinates of many animal societies tolerate group-living remains a pertinent question in evolutionary biology. The ecological constraints and benefits of philopatry hypotheses have the potential to explain the maintenance of group-living by specifying the ecological conditions favouring delayed dispersal over independent breeding by subordinates. In this study, I used field ...

2002
Ladislav Miklos

Development of the general ecological model (EM) of the CSSR has been included in the state program for environmental policy the Ecoprogramme of the CSSR at a scale of 1 : 1 000 000 for the entire Czechoslovak territory and at a scale of 1500 000 for the Czech Socialist Republic (CSR) and the Slovak Socialist Republic (SSR). The objective of the first EM stage was to make a survey of spatial di...

2006
Sumatra Nord

Rates in rupees are valid in India & South Asia only / Les tarifs en roupies sont valables en Inde et en Asie du Sud seulement A vegetation map may be considered in different ways, for instance as a physiognomic map showing the present state of the vegetation, or as a land use survey map. A useful purpose of this kind of map is to show the possibilities of improving production. For this we must...

2004

A Workshop to develop a “Decision Framework for Seismic Survey Referrals” held in March 2003 produced an inventory of ecological factors that DFO should consider when dealing with referrals for seismic surveys in Canadian waters. The workshop also discussed the sources of uncertainty about effects of seismic sounds on those ecological factors, and ways that the uncertainty could be presented in...

The aim of this study was to investigate the relationship between ecological factors and the distribution of rangeland habitats of Sumac shrub (Rhus Coriaria L.) and to determine the range of changes in effective environmental factors to interpret the best distribution of Sumac habitats in Khorasan Razavi province within the heights overlooking Khanik Valley in Brakuh , Kalat district of Gona...

2000
Ulf Dieckmann

Dwarf individuals are observed in many species of freshwater fish. This paper studies the potential causes of such stunted growth. We present a model which describes the effect of growth conditions on the ageand size-structure of fish populations. The model parameters are chosen to characterize a Eurasian perch population. Two possible causes of stunting are identified: resource limitation and ...

Journal: :Proceedings. Biological sciences 2012
Bradley J Cosentino Christopher A Phillips Robert L Schooley Winsor H Lowe Marlis R Douglas

Theory predicts that founder effects have a primary role in determining metapopulation genetic structure. However, ecological factors that affect extinction-colonization dynamics may also create spatial variation in the strength of genetic drift and migration. We tested the hypothesis that ecological factors underlying extinction-colonization dynamics influenced the genetic structure of a tiger...

Journal: :Geospatial health 2011
Paul J Maliszewski Ran Wei

The 2009 H1N1 influenza A virus subtype (H1N1) pandemic had a large impact in the United States of America (USA), causing an estimated 192,000 to 398,000 hospitalizations and 8,720 to 18,050 deaths between April 2009 and mid-March 2010. Recent research on the 2009 H1N1 pandemic has largely focused on individual, non-spatial demographic characterizations (e.g. age and race/ethnicity) associated ...

Journal: :جنگل و فرآورده های چوب 0
سیدمعین الدین زمانی دانشجوی کارشناسی ارشد جنگل داری دانشگاه یاسوج، ‏یاسوج، ایران رقیه ذوالفقاری عضو هیئت علمی ‏‏دانشکدة کشاورزی و پژوهشکدة منابع طبیعی دانشگاه یاسوج، ‏یاسوج، ایران سهراب الوانی نژاد عضو هیئت علمی ‏‏دانشکدة کشاورزی و پژوهشکدة منابع طبیعی دانشگاه یاسوج، ‏یاسوج، ایران

today, determination of the ecological species groups for current and future situation of forest and its relationship with environmental factors is necessary for forest management. for this purpose, 50 plots were established in altitude range of 2091- 2811 meters above sea level and 600 hectare in protected area of western dena. four ecological groups was identified using twinspan analysis that...

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