نتایج جستجو برای: abundance
تعداد نتایج: 80674 فیلتر نتایج به سال:
Water hyacinth (Eichhornia crassipes) is native to the Amazon basin and is one of the worst aquatic weeds in the world. It has been an invasive species in aquatic ecosystems of northern Iran since 2011. The use of herbicides as a method of plant control is common and efforts are made to select a formulation with the least impact on the environment. In the current study, three types of herbicide...
Development of the entrepreneurship space by helping to nurture entrepreneurs and increase the attitudes, abilities and aspirstions for entrepreneurship has a positive effect on the economic and social growth of societies. Because entrepreneurship is a source of innovation, employment, and economic growth and development. Therefore, determine the factors affecting of the entrepreneurship space ...
The relationship between some habitat factors and fish assemblage was analyzed in the Taleghan River, Alborz Province, Iran. Fish specimens from thirty-three sites were sampled by electrofishing device in October 2014. The habitat parameters, including elevation (m), water depth (cm), river width (m), river slope (%), current velocity (m.s-1), number of large stone (> 15 cm), average stone diam...
Species composition, relative abundance, absolute abundance and biomass of sturgeon species were studied during the years 2008-2009. Eighty five stations were covered in the stratified random sampling design in depths less than 1Om using 9m bottom trawl (head line) and in depths more than 10m using 24.7m bottom trawl (head line). More than 70 specimens of Acipenser persicus were caught during t...
The Hojdek Formation in the Kale-shur area consists of alternation of fine quartz arenitic-arkosic sandstones with dark gray to green shales and coal seams. This formation includes relatively well-preserved plant macrofossils which are studied here for the first time. 15 species of 9 genera belong to different orders such as Equisetales, Filicales, Sycadales and Pinales have been determined in ...
In this study abundance and composition of Vibrio spp. In water and sediment of inlet Chanel and shrimp pond during the entire crop cycle were done in Gowater shrimp complex. Samples of source (Inlet chanel) water and pond water werecollected one day prior to filling the pond with water and thereafter at twenty day intervals after stocking at three pre-determined sampling locations in two po...
The study and research of abundance and diversity variation of fish larva (Ichthyoplankton stages) was done in Gowatr Bay during autumn 2006 - summer 2007. Five stations were selected for sampling, and Bongo-Net with 300µ mesh size was towing from bottom to surface. During of survey, totally 531 larvae belong to 11 families were collected and identified. The mean abundance estimated 12.17 larva...
The spatial distribution of soil organisms is influenced by the plant cover, thus resulting in a horizontal mosaic of areas subjected to gradients of nutrient availability and microclimatic conditions.This study was conducted to investigate the spatial variability of soil macrofauna in relation to vegetation density in the riparian forest landscape of Karkhe. The vegetation density was determin...
The study on physiochemical factors and primary production of the aquatic ecosystems is important to know the characteristic of environment and capacity of recharge. Mahshahr creeks are the most important creeks in Khuzestan, Iran. In this study, variations in physiochemical factors, chl-a and primary production in 3 regions (Mahshahr, Zangi, and Moussa entrance creeks) were evaluated in 2 mont...
The objectives of this study were to determine the diversity, seasonal dynamics and abundance of ticks infesting cattle in Isfahan zone, Iran. The study was conducted in three traditional cattle farms. No acaricides had been applied to cattle at the selected farms. Adult ticks were collected twice per month from different parts of the cattle's body. Environmental data, including relative humidi...
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