نتایج جستجو برای: species diversity
تعداد نتایج: 692837 فیلتر نتایج به سال:
Trees are the most important biological elements of forest ecosystems. The variability of the tree species composition inhabiting in the Oriental beech forest, not only forms different forest types but also has a remarkable impact on the species diversity of forest floor plants, due to the existence of trees in the overstory layer. In this research, forest types of an an Oriental beech were ide...
Plant species distribution, composition and diversity in deserts of arid and semi-arid areas, especially saltland; depend on soil physical and chemical gradients. The aim of this research was to investigate changes in the plant species diversity and richness along a soil salinity gradient in the margin rangelands of Petregan Playa. After vegetation zoning in relation to soil salinity, random-sy...
in this study, species richness, evenness and vegetation biodiversity were investigated in stabilized and non-stabilized cut edge areas of chachkam district forest roads in sari forest of iran. 18 micro plots 1×1m (36 micro plots) were sampled to carry out this research on two cut edge areas. number of trees, shrubs and herbaceous were recorded in each micro-plot. significant difference was inv...
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...
Fish sampling was conducted to evaluate the species diversity of fish in 4 stations in Sanandaj Azad dam ecosystem seasonally from summer of 2017 to spring of 2018. A total of 1057 fish were caught in 12 species, of which more than 80% were caught in the lake behind the dam. The Cyprinidae family had 11 species with the most species diversity and only Sasanidus kermanshahensis belonged to the N...
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...
silvicultural operation need to notice the species diversity. to this study gomarlang district in marivan region, northern zagros forest was selected. in this study 30 circle sample plots (500 m2) were collected by random method. in every sample plot the kind of species and number of trees and shrub were recorded. in the sample plots the micro plots of 5 m by 5 m (i.e. area of 25 m2) were desig...
silvicultural operation need to notice the plant species diversity in forest. to this study gomarlang district in marivan region, northern zagros forest was selected. selected 100 ha area because have similar physiography condition (north aspect and 1650 to 1800 m s.a.l. in study area 100 micro plots of 5m by 5 m (25 m2) including the species and the numbers of this species randomized-systemati...
one of the main objectives of ecosystem management is to preserve the speciesdiversity. many researchers regard higher species diversity as the stability of ecologicalsystems. the aim of this study is to investigate the stability and relationships betweentopographical factors with diversity indices in ghorkhud mountainous rangeland innorthern khorasan province, iran. for data sampling (2012), l...
Plant diversity and vegetation distribution in an area are related to the soil physical and chemical properties. The knowledge of relationships between species diversityand soil parameteris essential for sustainable ecosystem management. This study was conducted to investigate the relationships between soil factors and species diversity indices in the protected rangelands of Lashgardar, Malayer...
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