نتایج جستجو برای: evenness and diversityheterogeneity indices were calculated thus

تعداد نتایج: 16860173  

The Hezar-Masjed Mountain range is one of the main highlands of the northeasten Iran. The vegetation of its upper elevations has been poorly studied. This study aimed to compare the plant biodiversity of different aspects of the Hezar-Masjed Summit. A total number of 139 random 1m2 plots were recorded from different aspects of the study area. In each plot, the abundance and canopy cover percent...

Journal: :حفاظت گیاهان 0
زهره خسرویان چترودی حسین صادقی نامقی مجتبی حسینی

pollination and pest control are perhaps the best-known ecological services performed by hover flies. the species diversity and their abundance have an influential impact on the ecological services provided by this family. to find out species diversity of adult flower flies associated with agroecosystems in kerman province, a biodiversity survey using insect net and color water traps was conduc...

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...

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه پیام نور - دانشگاه پیام نور استان تهران - دانشکده مدیریت و اقتصاد 1391

abstract nowadays, industries cannot play a crucial role in national and international competitions. the tourism industry is no exception. tourism industry development as the most important economic sector and income generation is one of the key challenges of economic development in the world. therefore, countries were successful that take advantage of the capabilities of tourism sector using ...

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...

Journal: :journal of rangeland science 2014
mohammad jankju fariba noedoost

rangeland ploughing and cultivation using dry land farming crops may be amajor reason for the destruction of natural resources in the semiarid and sub-humid regionswhich may significantly change the composition and reduce the stability of the affectedcommunities. in present research, an abandoned ploughed site was compared with a nearbyreference site in the semiarid rangelands of baharkish, quc...

Introduction and purpose: Ticks as biological vectors and reservoirs of diseases, such as Crimean-Congo hemorrhagic fever (CCHF), have an important role in the transmission of pathogens to humans and animals. In this regard, this study aimed to determine the biodiversity indices, distribution, and fauna of the vectors of CCHF in Ahvaz, Iran. Methods: The tick samples were collected and identif...

2015
Tarald O Kvålseth

Various properties have been advocated for biological evenness indices, with some properties being clearly desirable while others appear questionable. With a focus on such properties, this paper makes a distinction between properties that are clearly necessary and those that appear to be unnecessary or even inappropriate. Based on Euclidean distances as a criterion, conditions are introduced in...

Journal: :journal of rangeland science 2011
negar davari mohammad hassan jouri ali ariapour

the diversity and richness of species are of important components to evaluate the health of ecologic system of rangelands. this research was conducted to investigate the biodiversity in riparian and neighboring areas via comparison of indices in javaherdeh rangeland of ramsar. plot-transects was randomly used to estimate diversity, richness, dominance, and evenness indices in two regions. multi...

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه شیراز - دانشکده علوم 1392

gol-e-gohar iron ore mine of sirjan in southern part of iran is a large open pit that operates below the groundwater table and during mining operation, dewatering is required to prevent operation processes from flooding. current operation is going on by digging wells in or out of the pit and pumping to prevent flooding. as a result of the former dewatering operation a vast deep cone of depressi...

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