نتایج جستجو برای: aqueous species diversity
تعداد نتایج: 771354 فیلتر نتایج به سال:
our planet is threatened by nuclear wars, climate change and degradation of biodiversity. the first two dangers are relatively focused on, but biodiversity degradation is not properly considered yet. species diversity is mostly composed of biodiversity and is considered an index of changes in ecosystems. many of researchers think of higher species diversity as an index of bio-system’s stability...
چکیده ندارد.
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...
The aim of the study was to investigate affecting environmental factors on functional diversity indices and species diversity for the fluctuation of the management according to the ecological conditions in Raver rangeland. To determine the functional attributes of rangeland plants, 12 height points were selected along elevation gradient those were distance between them100 meters. 5 sampling plo...
This study aimed to compare plant species diversity indices (diversity and richness) and some physico-chemical properties of soil among forest, ecotone and rangeland habitats. Vegetation sampling was done randomly at each habitat. One dominant community was selected in each habitat and one key area was distinguished in each community and 8×1m2 plots were randomly established in each key area. I...
The species diversity of bumblebees was investigated in two provinces, Tehran (Fasham, Zayegan) and Qazvin (Alamut, Wikan) in central Alborz during 2005-2006. Three casts of queen, worker and male bumblebees were collected during spring and summer in six dates in the two mentioned regions. Sampling of adult bees in Wikan was done from 26 July 2006 until 19 September 2006, and in Zayegan from 24...
This study aimed to investigate plant species diversity in the ecological species group in relation to the environmental factors. A study area of 216 ha in the southeast of Baghmalek on which seventy 20×20 m plots were established according to the random-systematic method was selected. Soil properties and physiographic factors were recorded at each plot. Herbaceous species composition was recor...
The species diversity of bumblebees was investigated in two provinces, Tehran (Fasham, Zayegan) and Qazvin (Alamut, Wikan) in central Alborz during 2005-2006. Three casts of queen, worker and male bumblebees were collected during spring and summer in six dates in the two mentioned regions. Sampling of adult bees in Wikan was done from 26 July 2006 until 19 September 2006, and in Zayegan from 24...
Exclosure is considered as a management method to improve vegetation. This study aimed to evaluate the effects of exclosure on species diversity in Zayanderod dam station in Chadegan, Isfahan. The study area was stratified based on the various management types and slope directions, and samples were collected randomly in each layer. Four perpendicular transects, 500m in length were established a...
Numerical and parametrical indices are two of the most important and most widely used indices for assessing biodiversity in different societies. Nevertheless, their efficiency and selection in various ecosystems has always been one of the challenging issues of ecology. In this study, the numerical indices of diversity, richness and eveness, as well as abundance–ranking distribution models inclu...
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