نتایج جستجو برای: simpson diversity

تعداد نتایج: 191705  

Journal: :بوم شناسی کشاورزی 0
اشکان عسگری کورس خوشبخت سعید صوفی زاده جعفر کامبوزیا

evaluation diversity of agricultural plants and effectiveness of management factors in non-hunting of gharaviz abstract biodiversity is the basis of agriculture. sustainable agriculture both promotes and is enhanced by biodiversity. during present study, agrobiodiversity and management factors were investigated in three villages of gharaviz area and four villages in surroundings area, in sarpol...

F. Fahimipoor M. A. Zare Chahouki M. Goldansaz M. Jafari Z. Mohhebi

Plant Diversity conservation is a main objective in rangelandmanagement. Plant diversity is a suitable index for showing the changes ofvegetation in rangelands and has a high correlation with ecosystem parameters.Therefore, using this index it is possible to find the changes and manage theecosystem correctly. The current research was performed to determine the speciesdiversity in Fashandak rang...

Journal: :محیط زیست طبیعی 0
زهرا نوری دانشجوی دکترای جنگلداری، دانشکده منابع طبیعی، دانشگاه تهران، ایران جهانگیر فقهی دانشیار گروه جنگلداری، دانشکده منابع طبیعی، دانشگاه تهران، ایران قوام الدین زاهدی امیری دانشیار گروه جنگلداری، دانشکده منابع طبیعی، دانشگاه تهران، ایران رامین رحمانی دانشیار گروه جنگلداری، دانشگاه گرگان، ایران

the aim of this study is to investigate the tree species' diversity in a region with no management planning and introduce the calculated indices as the norm for sustainability assessment. dbh of all tree individuals, and their stories were recorded in the inventory grid (75 m × 100 m) sample plots. subsequently, richness, evenness (simpson, smith & wilson) and heterogeneity (simpson, shann...

2011
Antoine Collin Phillippe Archambault Bernard Long

Epi-macrobenthic species richness, abundance and composition are linked with type, assemblage and structural complexity of seabed habitat within coastal ecosystems. However, the evaluation of these habitats is highly hindered by limitations related to both waterborne surveys (slow acquisition, shallow water and low reactivity) and water clarity (turbid for most coastal areas). Substratum type/d...

Journal: :Applied and environmental microbiology 2010
Emilie Lyautey Zexun Lu David R Lapen Graham Wilkes Andrew Scott Tanya Berkers Thomas A Edge Edward Topp

We investigated the prevalence and diversity of Escherichia coli strains isolated from surface waters from multiple watersheds within the South Nation River basin in eastern Ontario, Canada. The basin is composed of mixed but primarily agricultural land uses. From March 2004 to November 2007, a total of 2,004 surface water samples were collected from 24 sampling sites. E. coli densities ranged ...

Abbaspour, F., Gharaei, A., Iezadi, G.H., Mirdar Harijani , J.,

A biological assessment of the Tang Sorkh River (Iran) was studied from July 2013 to August 2014 using benthic macroinvertebrate communities. Samples were gathered every two months, from five stations using a Surber sampler( 30×30cm), fixed in formalin (4%) and then separated and identified in the laboratory. Environmental conditions (current velocity, temperature, depth, width, dissolve oxygen...

2005
PRANAB K. SEN

The celebrated Gini(-Simpson) biodiversity index has found very useful applications in ecology, bio-environmetrics, econometry, psychometry, genetics, and lately in bioinformatics as well. In such applications, mostly, categorical data models, without possibly an ordering of the categories, crop up, which may preempt routine use of conventional measures of quantitative diversity analysis. Furth...

Journal: :پژوهش های علوم و فناوری چوب و جنگل 0

the aim of this study is comparison of soil characteristics and biodiversity in plantation of bald cypress and caucasian alder forest stands in kludeh region (mazandaran province). in order to study biodiversity in forest stands and control region, 10 sample plots (releve) were selected and the name and abundance of plant species of the forest floor were recorded. biodiversity of herbal plants ...

This study aims to identify and determine species diversity and richness of the Gastropods of intertidal zone of Bushehr seaport coastal field and assess ecological status of the area using Welch index. Sampling was carried out at 6 stations in Bushehr seaport in winter and summer seasons during 2013-2014. Sampling bed sediments was done three times in each station and Gastropod samples were co...

2006
Carla Cresoni-Pereira Fernando Sérgio Zucoloto

As highly adapted animals with great evolutionary diversity, the insects are considered important subjects for studies concerning nutrition and feeding behavior. Although they have developed morphological, physiological and behavioral means to guarantee acquisition and utilization of nutrients, the insects are constantly facing more immediate problems when food quality varies not only in space ...

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