نتایج جستجو برای: species evenness

تعداد نتایج: 548668  

Journal: :محیط زیست طبیعی 0
مرضیه نوبخت دانش آموخته کارشناسی ارشد، دانشکده منابع طبیعی، دانشگاه گیلان، ایران حسن پوربابایی دانشیار دانشکده منابع طبیعی، دانشگاه گیلان، ایران مرضیه بیگم فقیر عضو هیأت علمی دانشکده علوم پایه، دانشگاه گیلان، ایران رویا عابدی دانش آموخته کارشناسی ارشد، دانشکده منابع طبیعی، دانشگاه گیلان، ایران

in order to investigate variations in plant diversity in dr. dorostkar's forest reservoir, located in gisoum talesh, 44 sampling plots were applied by the randomized-systematic method. the diameter of all tree species (dbh?5 cm) was measured in 400 m2 (20×20 m) square sampling plots. in addition, the number of individuals of shrubs and saplings (dbh?5 cm) were enumerated in circular 100 m2...

2009
Minsheng You Liette Vasseur Jacques Régnière Yunkai Zheng

The concept of biodiversity can be simply defined as the sum of all biotic variation from the level of genes to ecosystems. Biodiversity at the species level, frequently called “species diversity”, is a core concept of ecological community and conservation research. To date, however, no single number can fully capture such a concept without loss of information, although many attempts have been ...

Journal: :محیط زیست طبیعی 0
حمزه جعفری سرابی دانشجوی کارشناسی ارشد جنگلداری دانشکده کشاورزی، دانشگاه لرستان، ایران بابک پیله ور استادیار گروه جنگلداری دانشکده کشاورزی، دانشگاه لرستان، ایران غلامحسین ویس کرمی کارشناس ارشد علوم گیاهی، سیستماتیک گروه جنگلداری دانشکده کشاورزی، دانشگاه لرستان، ایران جواد سوسنی استادیار گروه جنگلداری دانشکده کشاورزی، دانشگاه لرستان، ایران

forest reserves are one of the most important approaches in ecosystem management in iran. in order to determine the effects of reserve management on plants diversity (woody plants and ground flora) in three zones (core zone, buffer zone, and transmission zone of chamhesar pear forest reserve), we mapped land form units. then 18 main sampling units (20×50=1000 m2) distributed randomly were chose...

Determination of factors affecting on species distribution and diversity, especially in desert areas is the most important factor in rangeland ecosystems management for encountering biological stress. In order to evaluate the effect of physiographic factors on plant biodiversity in natural ecosystems of Kakhk Gonabad, this research was conducted in spring 2014. First, by overlaying four maps of...

2015
Koji Sugie Koji Suzuki Ahmed Moustafa

Traditionally, biodiversity has often been estimated on the basis of abundance partly due to the need for complicated measurements of biomass. Here, we conducted robust measurements of the community composition and of the size structure of diatoms in the North Pacific to evaluate the importance of biomass on the biodiversity. We found that the two most useful evenness indices increased in most ...

Hamid Ahani, Hamid Jalilvand

Forests are biologically diverse systems, representing some of the richest biological areas on Earth. They offer a variety of habitats for plants, animals and micro-organisms. However, forest biodiversity is increasingly threatened as a result of deforestation, fragmentation, climate change and other stressors. Biodiversity is the variation of life forms within a given ecosystem, biome, or on t...

2010
Muhammad Aslam

Moths were collected from different parts of Peshawar during June to August in 2007 to determine their diversity, species richness and evenness. A total number of 774 moth specimens were collected by using simple light traps operated from dusk to dawn daily for sixty nights. The moths caught were identified up to family level. Families Noctuidae, Pyralidae, Arctiidae, Geometridae, Sphingidae an...

2016
Bridget Hennessy

The dune system of Lake Michigan at Sturgeon Bay leads back thousands of years into the surrounding forest and intermittently form small pools in the swales of the dunes. Maintained by rainwater and including a unique composition of species and chemistry, the pools of the dunes and the surrounding terrestrial life show a pattern of diversity unique to dune swales. Percent cover of species at fo...

2015
Max A. Henschell Christopher R. Webster David J. Flaspohler Chad R. Fortin Eric Gordon Lamb

United States energy policy mandates increased use of renewable fuels. Restoring grasslands could contribute to a portion of this requirement through biomass harvest for bioenergy use. We investigated which plant community characteristics are associated with differences in biomass yield from a range of realistic native prairie plantings (n = 11; i.e., conservation planting, restoration, and wil...

ژورنال: مرتع 2022
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Background and objectives: In order to properly manage rangeland ecosystems, it is necessary to study the relationship between ecological factors in nature such as elevation, climate and soil factors with vegetation and living organisms. In this regard, the present study was conducted to investigate the relationship between species diversity and environmental factors (Physical and chemical char...

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