نتایج جستجو برای: index species

تعداد نتایج: 931450  

Journal: :international journal of aquatic biology 0
harekrishna jana vidyasagar university keshab chandra mondal vidyasagar university chiranjit maity vidyasagar university arpan das vidyasagar university suman kumar halder vidyasagar university abhijit mitra university of calcutta

the effect of microbial load on the condition index of the edible oyster, saccostrea cucullata were analysed on monthly basis during 2010 and 2011 from the three different stations (namkhana, frasergaunge and sajnekhali) of indian sundarbans. the results showed significant variation with respect to microbial load between stations and seasons, which is reflected in the tissue of edible oyster. s...

2009
Nicklas Jansson Karl-Olof Bergman Mats Jonsell Per Milberg

The saproxylic beetle fauna on old oaks was sampled in four regions of southern Sweden using two methods: window and pitfall trapping. The aim was to test a way of finding indicator species which can be used to identify sites with high species number or that scored high on a conservation priority species index, based on occurrence of red-listed species. From 92 sites surveyed, in total 164 spec...

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...

2004
R. Biggs R. J. Scholes B. Reyers

The Southern Africa Millennium Ecosystem Assessment developed an index for quantifying the state of biodiversity. The Biodiversity Intactness Index (BII) operates at the species level, and is based on changes in species abundance, rather than changes in richness brought about by extinction. The BII uses spatial data on species richness and land use activities per ecosystem type to weight estima...

The forest structure and stand composition are controlled by several physiographic factors, because these factors play an important role in control the physical and chemical conditions of the environment, including access to light, soil moisture, and nutrients. In this study, the physiographic characteristics indices of the study area including landform index, terrain shape index and aspect slo...

The taxonomic affinity of six species of Crocus (C, cancellatus subsp. Damascenus C. almehensis, C. gilanicus, C. sativus, C.pallassi subsp. haussknechtii,C. speciosus subsp. speciosus) from Iran were studied usingdifferent electrophoresis techniques. The similarity index of the species was computed by comparison of protein bands of - Corm and seed tissues, and the related dendrogms of affi...

Abdoli, A., Kalantarian, S.M., Kiabi, B.H.,

The gobies are non-commercial fishes in the Iranian waters of the Caspian Sea for which population dynamics and stock status are poorly known. In this survey, we tried to define species diversity and catch per unit effort (CPUE) of Gobiidae by using beach seine nets in Salmanshahr, the southern Caspian Sea. From March 2011 to April 2012, 224 specimens representing 4 gobiid species, belonging to...

ژورنال: مرتع 2022
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Abstract Background and objectives: Prediction of species richness and diversity patterns are used to develop conservation strategies for biodiversity under regional and global environmental changes. Since modeling the distribution of plant species can provide useful and important information about identifying and introducing potential habitats of plant species, and also few studies have been ...

Journal: :جنگل و فرآورده های چوب 0
سمیه کرمی راد دانشگاه تهران احسان عبدی دانشکده منابع طبیعی باریس مجنونیان دانشگاه تهران وحید اعتماد دانشگاه تهران هرمز سهرابی دانشگاه تربیت مدرس

road construction is one of the effective factors for ecological changes which affects diversity and species composition in forest roads edges. this research was performed in kheirud forest to evaluate herbaceous diversity and tree regeneration establishment in different distances from road edge. for this purpose, we sampled herbaceous and tree species regeneration in 0,5,10,25, 50 and 100 m di...

Journal: :global journal of environmental science and management 2015
r.n. lohe b. tyagi v. singh p. tyagi d.r. khanna

although water and land pollution are very dangerous, air pollution has its own peculiarities due to its transboundary dispersion of pollutants over the entire world. in any well planned urban set up, industrial pollution takes a back seat and vehicular emissions take precedence as the major cause of urban air pollution. in the present study, air pollution tolerance index was calculated for var...

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