نتایج جستجو برای: species diversity index

تعداد نتایج: 1072319  

The main purpose of this study is to investigate the quantitative and qualitative characteristics of dominant tree species and their regeneration status in the Arasbaran forests. Data were collected by transect sampling and regeneration was assessed by plot with an area 100 m2. In the sample plots, we recorded information on species type, diameter at breast height, height, quality of seedlings ...

Assessment of forest soil and vegetation characteristics provides basic and essential information for the protection and rehabilitation measures in forest ecosystems. Therefore, regard to the importance of this issue, the distribution of different soil properties and vegetation diversity in relation to conservation management and degradation investigated in the oak forests of Ilam province usin...

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه فردوسی مشهد - دانشکده علوم 1376

saluk mount is selected for devonian biostratigraphy. this area located at southwest of bojnurd. in this study three sections are selected and two sections, chahar-borj and tabar sections with a thickness of 650 m, which consist mainly of calcareous sediments was studied in detailed but third section, qelli section, with a thickness of about 450m which consist mainly of sandstone and evaporates...

1998
DEBORAH E GOLDBERG ESTABROOK

0 Species richness typically increases with the number of individuals sampled\ although many ecological processes that in~uence species richness are also well known to depend on density of individuals[ We separated the e}ects of density on species richness that are due to sampling\ from those due to density!dependent ecological processes such as competition or predation\ by manipulating the den...

2016
Peiqin Li Zhou Wu Tao Liu Yanan Wang

This study investigated the biodiversity, phylogeny, and antifungal activity of endophytic fungi isolated from Zanthoxylum bungeanum. A total of 940 isolates obtained were grouped into 93 morphotypes, 43 species, and 23 genera, which were authenticated by molecular identification based on rDNA internal transcribed spacer (ITS) sequence analysis. A high diversity of endophytic fungi from Z. bung...

Habib Yazdanshenas Hossein Arzani Hossein Azarnivand Malihe Nasiri Mohammad jafari

Understanding the plant species diversity could be used as an importantindicator applied for the natural areas management. The aim of this study was toinvestigate the relationships between soil characterizes with distribution and diversity ofplant in vegetation types in Karvan district (located in west of Isfahan province). For thispurpose, three vegetation types were selected as follows: Scari...

2008
J. C. Gaertner G. Sancho D. Itano

This study provides a baseline measure of pelagic fish species diversity around fish aggregating devices (FADs) in the Western Indian Ocean. Using data from visual censuses made by SCUBA divers around drifting FADs we (1) analysed 11 diversity indices describing 4 main components of pelagic diversity: number of species, evenness, taxonomic diversity and rarity and (2) discussed the viability of...

Journal: :Journal of environmental biology 2008
Ramazan Ozcelik Altay Ugur Gul Jan Merganic Katarina Merganicova

We studied the effects of stand parameters (crown closure, basal area, stand volume, age, mean stand diameter number of trees, and heterogeneity index) and geomorphology features (elevation, aspect and slope) on tree species diversity in an example of untreated natural mixed forest stands in the eastern Black Sea region of Turkey. Tree species diversity and basal area heterogeneity in forest ec...

2013
Jie Zhang Xue Zheng hu Jian Xiaowa Qin Fenghui Yuan RunJie Zhang

The diversity and community structure of arthropods in an organic double-cropped rice ecosystem in Guangdong Province, China was studied. We compared the arthropod communities in the early season (Apr-Jul) crop to those in the late season (Aug-Nov) crop in 2009. The comparisons were undertaken using a combination of community assessment approaches, including morphospecies richness, the Shannon-...

2006
Karline soetaert

Diversity indices, although designed for comparative purposes, often cannot be used as such, due to their sample-size dependence. I t is argued here that this dependence is more pronounced in h~gh divers~ty than in low diversity assemblages and that indices more sensitive to rarer species require larger sample sizes to estimate diversity with reasonable precision than indices which put more wei...

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