نتایج جستجو برای: index species
تعداد نتایج: 931450 فیلتر نتایج به سال:
based on the latest records of typhlops vermicularis merrem, 1820 from iran, this species is distributed in the northern and southern regions of the country. in this study, new records of typhlops vermicularis are presented and it is shown that distribution range of this species is extended towards the eastern and western iran, and according to the new distribution map, it can be assumed that t...
Diversity is one of the most important issues in studies of vegetation ecology. This study was carried out in research forest of Tarbiat Modares University for surveying herbaceous and woody species diversity in relation to topographical factors (altitude, slope and aspect). For this purpose, 48 plots 400 m2 (20×20 m) were established in the region using selective sampling method. Then, the nam...
The quantitative description of forest structure can be regarded as one of the most usable working tools in modern forest management.The study aims at analyzing the stand structure in unlogged beech forests using nearest neighbor indices. Data collection was done in compartment 319 with an area about 48 ha in Educational and Experimental Forests of University of Tehran. Species and DBH of all ...
This study aims to identify and determine species diversity and richness of the Gastropods of the intertidal zone of Bushehr seaport coastal area and assess the ecological status of this area using Welch index. Sampling was carried out at 6 stations in Bushehr seaport in the winter and summer seasons during 2013-2014. Bed sediment sampling was done three times in each station and Gastropod samp...
Regarding high economic and conservative values of Zagros forests, and livelihood dependency of local people these recourses, determination of sites with higher conservation index can help us to maintain biodiversity of these forests more efficiently. Therefore, 49 plots with 450 m2 in area accompanied by 1, 10 and 45 m2 subplots were taken as systematic random design in research forests of Yas...
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...
biodiversity plays a crucial role in stability and productivity of natural ecosystem. the main goal of this research was to classify ecological groups in steppe rangeland and investigate their relationships with plant diversity indices. therefore, fifty different land unit tracts (lut) were identified in khod-neuk basin, yazd province, iran, in 2010. vegetation and soil samples were taken in th...
in order to investigate diversity of weed species in wheat fields in eastern parts of mashhad, an investigation was made in the year 2009. wheat fields was classified based on the acreage from 3-5 ha, 5-10 ha and higher than 10 ha. sampling was made randomly by a quadrate 0.5×0.5 in 9 fields of each group from jointing to heading of wheat in tow separate stages. type and total number of weeds w...
Biodiversity plays a crucial role in stability and productivity of natural ecosystem. The main goal of this research was to classify ecological groups in steppe rangeland and investigate their relationships with plant diversity indices. Therefore, fifty different Land Unit Tracts (LUT) were identified in Khod-Neuk basin, Yazd province, Iran, in 2010. Vegetation and soil samples were taken in th...
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