جستجوی مقالات مرتبط با کلیدواژه « پوشش گیاهی » در نشریات گروه « زیست شناسی »

To conduct this research, first by preparing the land use map using Landsat 8 OLI sensor images and its combination with geological map, homogeneous units were determined and sampling was done in randomly-systematically in the representative areas of each plant community. Sampling was done along 3 transects of 500m which were vertical, in each site. In each transect placed 10 plots of 3×3m2 at a distance of 50 meters from each other And characteristics related to any plant including vegetative form, scientific name, genus, canopy percentage were harvested. Also, 48 soil samples were taken from a depth of 0-20cm and properties such as soil texture, organic matter, salinity, pH and adsorption ratio sodium were measured. To classification plant communities and investigate the relationships between these communities and soil properties using cluster analysis and principal components analysis respectively in Rstudio software. According to the cluster analysis results, four plant communities were identified and tamarix stricta and Suaeda fruticosa plant species with shrub-shrub vegetative form had the highest frequency with 37.2% and 26.5%, respectively. Results of ANOVA indicated that there were significant differences between some soil properties in identified plant communities. There is also a relationship between the plant communities distribution and environmental factors (p<0.05). The results also showed that the most important factors affecting the establishment and distribution of plant communities in the study area are the percentage of sand, electrical conductivity, sodium absorption ratio and percentage of organic matter

The Booz Daghi region with an area of 62,000 hectares is located 47 kilometers from Maneh and Semelghan city. The floristic composition, biological, and chorological spectra of this area were investigated through several random collections in different habitats and vegetation types, as well as from 220 plots established in selected plant communities during the growing season of 2021. In this regard, 252 vascular plant species belonging to 173 genera and 53 families were recorded as native plants in the Booz Daghi region. The richest families were Asteraceae (31), Poaceae (25), Lamiaceae (22), and Fabaceae (21). The genera Astragalus L. (10), Allium L., Convolvulus L., and Stachys L. (each with 5 species) were the richest ones. Hemicryptophytes (31.3%) and therophytes (29.8%) were the dominant life forms of the region. A considerable number of species (63.5%) belonged to the Irano-Turanian region. The results of this study showed that the Booz Daghi region had a relatively rich flora that requires special attention and proper planning to protect its biodiversity.

Roe deer and Persian Squirrel are among indicator species of Zagros forests in the Bozin and Marakhil protected area. The aim of this study is to use vegetation indexes for investigate the trend of changes in vegetation indexes in the areas that species are present and also to compare their dependence on vegetation cover. 11 series of Landsat 8 satellite images during the period from 2013 to 2018 were used. Required pre-processing was carried out and then the NDVI and LAI were calculated for all of the mentioned images. Analysis was conducted in ENVI 5.3. Values of these indexes for the presence of each spices are provided and used along with the non-parametric Mann-Kendall method to determine the trend. K-mean clustering method was used to study the similarities of 2 species presence regions based on vegetation indexes. In order to clustering R3.5.2 was used.Results showed that there was a significant decrease in NDVI index in presence areas of Roe deer (P> 0.05) while based on the results, there was no significant change for Persian Squirrel. Changes in LAI in Roe deer habitat did not have a significant trend, but changes of this index for Persian Squirrel has an incremental and meaningful trend (P> 0.05). The results of clustering showed that the mentioned species have the possibility of coexistence in the central and northeastern parts of the region. The results demonstrated that vegetation indices can be used to monitor habitat changes.

The type of land use, the amount of vegetation and their management, play an important role in the carbon sequestration capacity of the ecosystem. Therefore, in order to estimate soil carbon sequestration over time affected by vegetation type, in Gonabad city, first using remote sensing data of ETM and TM satellite images, land use map of the city for the years 1387 and 1397 based on the maximum probability classification method. Similarity was provided. Vegetation index was also calculated for the images. In order to estimate the amount of soil carbon sequestration in the two years studied and to investigate the relationship between depth, texture and percentage of soil nitrogen with the amount of carbon sequestration in pistachio and wheat, soil test results and GPS points of these uses were prepared using independent t-test And regression relations data analysis was performed. The results showed that different land uses with different vegetation levels have different effects on soil carbon sequestration. So that the total amount of soil carbon sequestration in pistachio orchards in 1397; It had the highest rate of carbon sequestration per hectare. The study of the relationship between depth, texture and percentage of soil nitrogen with carbon sequestration showed that there is a positive relationship between the percentage of nitrogen, silt and soil clay and a negative correlation between sand and carbon sequestration.

Woody rangelands are a combination of tree plants in the upper stratum and herbaceous plants in the sub-stratum, both of which are interconnected. Upper stratum coatings have different effects on subterranean plants. The aim of this study was to investigate the effect of tree cover crown on the diversity of subspecies in the Nejdarre reserve. For this purpose, three tree species, Acer monspessulanum, Pistacia atlantica and Crataegus azarollus were selected, which have relative importance in the herbaceous composition of the upper stratum. Using one-square-meter plots, the percentage of vegetation covered under trees and rangeland open space between trees (micro sites) was recorded. Species diversity indices were then calculated for each of them. Data were analyzed by two-way ANOVA and Duncan tests. According to the results, open tree-free micro-sites have higher species diversity compared to tree-lined micro-sites. In addition, the north and south directions of the slopes were not significantly different in terms of species diversity. P. atlantica had allelopathic and depressive effects compared to other species and C. azarollus increased the diversity indices in some cases. The results of regression analysis between species diversity indices under morphological cover and morphological characteristics of trees showed that with increasing trees height and decreasing their shading diametre, the under-species diversity increased significantly. Therefore, in order to increase the diversity of under-species species, tree management should be carried out to increase height of tree. In breeding projects, measures should be taken to increase the species without allopathy in the tree plant community.

In recent years, Kani Borazan wetland in Mahabad has been at risk due to the drought crisis in the watershed of Urmia Lake, which mostly connected with human societies. Considering the importance of this environmental issue as well as the lack of grounded data using remote sensing technology and geographic information system, changes can be made in the region. Four Landsat 8 satellite images during 2013 to 2016 were investigated.for this purpose. The NDVI maps analysis was done within ArcGIS. Finally, small changes in the water range, dense vegetation, poor vegetation (marshland) have been estimated over the past four years. The results showed that vegetation cover increased in 2016 compared to 2013, while wetland area has decreased in recent years. Wetlands are indicator of climate change in a region. Due to the decrease in the extent and water level of the wetland, it is suggested that more precise conservation plans be applied to reduce and control water consumption in the catchment area of the area. It is also necessary to provide sustainable vegetation monitoring in the wetland.

It is very important in forest planning to recognize forest types and their classification in similar or different groups, their distribution pattern, mixture, frequency, dominance and abundance at the various area. Therefore, the purpose of current research is to identify, classify and introduce forest types, also determine some structural parameters and, other statistical components on these types. For this study, randomized-systematic sampling was used. After the statistical calculations, eighty sample plots were deployed. To understand the natural regeneration condition, five sub-plots were measured in each plot in four directions and the center of the plot. The seedlings height includes <30, 30-130 and, >130 cm was measured with decimeter precision. In this study, forest types have been classified based on factors such as physiognomy, dominance, species composition, physiographic conditions, and forest type extension. The results showed that 17 tree species belonging to 17 genera and 13 plant families were identified. The mean volume per hectare was equal to 317 silv, which beech, maple and hornbeam species have the highest proportion. The volume per hectare of beech stands includes 440.8 silv. Totally, the number of trees per hectare comprises 485 trees. More than 52% of the total regeneration belongs >130 cm height, 17.62% belongs 30-130 cm height and 30% belongs <30 cm height. Among the species, Diospyros lotus, Box-plants, Ironwood, maple, and beech constitute the majority of regeneration, respectively.

Vegetation distribution modeling, as a tool that uses statistical methods and GIS, plays an important role in examining the complex relationships between plant community distribution and influential environmental variables. These models are based on data on the presence and absence of species and their correlation with environmental variables and on the hypothesis that environmental factors control the distribution of plant species. One of the objectives of this study was to present a model for predicting the habitat distribution of plant species and to prepare a map for predicting their relative distribution by the logistic regression method. In this study, random sampling method was used to sample vegetation and soil in Molla Fahleh watershed area of Firoozabad, Fars province,. At each sampling point, 4 soil samples were taken from two depths of 0-15 and 15-30 cm. Soil physical and chemical parameters along with physiographic factors (slope, slope direction and elevation) were recorded for each sample. Habitat distribution modeling was performed by logistic regression method using SPSS software for major plant species in the region. According to the results, soil texture, organic matter, clay content, lime content, acidity, slope and height have the underlying role in the distribution of the studied species. The results show that the logistic regression method is able to provide an accurate prediction model most of the plant species in the area.

Understanding the rangeland ecosystem is the first step in managing these resources and determining land management and sustainable development programs.The aim of this study is to investigate the qualitative changes in the percentage of vegetation in the area of international wetlands of Golestan province. The study used Landstat satellite bands measuring TM and OLI during statistical years (1988-2018). In ENVI5.3 software, geometric correction and preliminary processing and FLASH algorithm were used for atmospheric corrections. To increase the accuracy of rangeland classification, NDVI map was prepared with TERSET software and And 4 classes of covered land (excellent, very good, good and poor) were obtained. The CROSSTAB technique also calculated changes during the years of study. Land area showed results The highest increase with very good vegetation is from 1540/93 to 2849.99 square kilometers And the largest reduction in area with well-covered lands was from 1369/46 to 68.94 square kilometers. During this time, the study area underwent changes The biggest reductions include the destruction of a well-covered class from 31.94 to 1.66 percent and its conversion to other users.Also, 13.46 square kilometers of good coverage has become poor coverage Which included the surrounding wetlands, rocky areas and rural areas.Good coverage that minimized area reduction There were pasture lands in use Class changes with good coverage indicated a reduction in area and vegetation And the temperature will rise The results showed that NDVI is a good measure for evaluating and monitoring vegetation changes and proper rangeland management.

A great plant diversity can be observed in Chaharmahal Bakhtiari Province, especially in the protected area of Tang-e Sayad, thus being environmentally important. In this study, the flora of the western part of this region (Dastgerd Mountain) was studied via a field survey in 2016-2017. Once every two weeks, various plants that had reached their full growth were collected together with all their plant organs from the rebellious area. Also, the plants whose flowering and fruiting stages had taken place at different times were gathered. A total of 216 species, which belonged to 35 families and 126 genera, were identified in the study area. Asteraceae, Brassicaceae, and Poaceae with 18, 15, and 13 genera were the largest families present in the region, respectively. Astragalus and Euphorbia were also the largest genera in this region in terms of number of species. Hemicryptophytes were the predominant vegetative form (48.6%) followed by therophytes (36.1%) in the region. Thirty native and 35 medicinal species were additionally reported in the area, respectively. One hundred and seventy species were related to Iran-Turanian elements (74%) as the most abundant corotype in the region. Examination of the collected species showed the presence of 33 less endangered species as well.

Studying of plant vegetation is a prelude to many researches and executive projects. Herbaria are permanent treasures of plant specimens for a region and the best source of information about the flora of the region. The present study is concerned with the identification of plant species of herbarium of Damghan University (DU, Semnan province). Based on the results obtained from the plant identification of herbarium specimens, a total of 311 species belonging to 237 genera and 68 families from Semnan province were identified. The most species richness families were Poaceae (23 genera, 32 species), Asteraceae (23 genera, 30 species), Lamiaceae (16 genera, 24 species), respectively. Also, the genus Bromus with 6 species, Salsola, Stachys and Prunus each with 5 species and Chenopodium with 4 species are the largest genera in the region. This study documents 122 medicinal and 8 halophytic plant species in the region. Moreover, 25 plant species were listed as threatened species based on the criteria of the International Union for Conservation of Nature.

Most of Lorestan is mountainous. Precipitation in the mountainous areas of the province is mostly snow (750 to 950 mm). Snow plays a role as a natural reservoir. Its gradual melting has led to the emergence of humid areas and the presence of more plants in mountainous areas. In this study, habitat factors of 5 mountainous sites of Lorestan province were identified and investigated. The collected parameters were analyzed by GGE biplot software. The results show that water regime, substrate and the EC have the greatest effect on the distribution of the species, pH did not show significant differences in habitats. The most ideal habitat is the Sumach Valley, and the Nozian are closer to ideal conditions. By identifying the super environments and their subdivisions, there are two distinct groups of wet mountainous areas: Wet mountainous areas above the timberline (Garin, Oshterankouh and Rimeleh highlands) and wet mountainous areas below the timberline (Neujian and Samag Chegeni Valley). In the region above the timberline, Iranian-Turanian elements have the highest proportion. The plant species of this group of wet mountainous areas are highly dependent on the cold and humidity of the snowfalls. The ecosystems in which they live are often very limited, fragile, small, and isolated. Due to the effects of climate warming and intensive grazing in highlands, they need strong conservation management and maintenance.

In this study, the flora of the Drakhtak Frieden area was investigated. A total of 265 species belonging to 184 genera and 42 plant families were identified in the area. Of these, 35 belong to dicots and seven to monocots. The most important plant families include Asteraceae (32 genera and 48 species), Brassicaceae (24 genera and 32 species), Poaceae (20 genera and 25 species). The genus Astragalus with 11 species and the genera Cousinia and Centaurea each with five species accounted for the largest share in the plant composition of the region. The geographical distribution of plant species showed that 52% of the plants belong to the Irano-Turanian regions. Subsequently, by and large, elements from the Irano-Turanian / Europe-Siberia / Mediterranean area are most present. Hemicryptophytes and trophytes accounted for the most (40.75%), with camphores, geophytes, and phanerophytes being the next levels. The vegetation of the area based on the physionomy is shrublands, that dominant species including Astragalus verus and Astragalus gossypinus. Of the identified plants in the region, 42 are endemic species and 82 species have medicinal value.

The Afus region with 1146 hectares area is located at 10 Km to Buin Miandasht region (Isfahan province) between the northern latitudes of 33° 05΄ and 33° 58΄ and the eastern longitudes 50° 02΄ and 50° 09΄. The purpose of the present study was to investigate the flora of the region. So, the plant species were collected from different places using the survey sampling method during spring, summer, and autumn 2017-2018 and were identified using valid resources. In this study, a complete list of the flora, life forms, chorotypes of plant elements, and endemic plants was prepared. The identified vascular plants in the region were mostly flowering with 184 species belonging to 37 families and 132 genera. Asteraceae (24 genera, 32 species), Apiaceae (12 genera, 12 species), Poaceae (11 genera, 13 species), and lamiaceae (9 genera, 13 species) were the most important families in this region, respectively. The largest genera were Astragalus (12 species), Euphorbia (5 species), Silene and Stachys (4 species), Cousinia, Fritillaria and Scorzonera (3 species) and Centaurea (2 species), respectively. The largest geographic floral element of the region was related to Irano-Turanian region with 136 species (73/9%). Hemicryptophytes (107 species, 58/15%), geophytes (25 species, 13/59 %), theophytes (24 species, 13/04%), chamaephytes (17 species, 9/24%), phanerophytes (7 species, 3/80%), and cryptophytes (4 species, 2/17%) made up the most important life forms, respectively.

 This research focuses on the Flora of Shabliz and Shoorom, an area with approximately 12000 hectares and an altitude range between 1300-3100 m above the sea level located in the eastern longitude 50°48' to 51°13' and the northern latitude of 30°59' to 31°16, 87 km west of Yasuoj City in Kohgiloyeh and Boyer Ahmad province. This Transect survey was performed during 1394 and 1395 AH (2015 and 2016). It showed that in this region, 409 species belonged to 270 genera and 73 families. The largest groups in the area were Asteraceae, Fabaceae, Brassicaceae, Lamiaceae, and Poaceae with 59, 40, 37, 30, and 26 species, respectively. In addition, Therophytes with 163 species (%40), Hemicryptophytes with 142 species (%34.7), Geophytes with 44 species (%10.7), Phanerophytes with 30 species (%7.3), and Chamephytes with 22 species (%5.3) were the largest biological types in the region. In terms of the geographical distribution, Irano-Turanian vegetative elements with 232 species (%60) and Irano-Turanian-Mediterranean elements with 39 species (%10) were the most important vegetative elements in the region. Out of 409 identified species, 56 species (13.6%) were endemic to Iran, 112 species (27.3%) were medicinal, and 88 species (21.5%) were toxic.

Fire affects vegetation and changes plant succession. In this paper, the vegetation of Sirachal Research Station, which burned in the summer of 2014, was studied and compared with the unburnt areas, based on biodiversity indices. The research was implemented as a factorial experiment in a completely randomized design. First, on the basis of physiognomy, the area was divided into three parts: shrubland, shrubland-rangeland, and rangeland. Each part was, then, divided into two sections, including a burnt area and an adjacent unburnt area (control area). In each area (burnt and unburnt), three sampling units were randomly assigned using PNP method, and vegetation measurements were subsequently performed. Based on data analysis, a total of 141 taxa were identified, belonging to 28 families and 95 genera, including one species of Gymnosperm, 19 monocotyledons and 121 dicotyledons in two burnt and unburnt areas of Sirachal Station. Based on the statistical analysis, using Past3 and SPSS softwares, there was no significant difference in the number of taxa between the vegetation of the burnt and unburnt areas. Of the indicators analyzed in Past3, the number of individual, the index of Menhinick's richness and the Shannon diversity index were significantly different in the treatments sampled from the burnt and unburnt areas. According to the Duncan test average, the number of individuals in the unburnt area, with a canopy cover below 25%, was greater than that in the burnt area, with the same canopy cover, however, no significant difference was observed between the individuals in the burnt area and unburnt area, with the same canopy cover of more than 25%. Also, the richness of the burnt area with a canopy of less than 5% is significantly higher than that in the unburnt area with the same canopy cover.

 This Floristic research focuses on Khamin Mountain Protected Area with 25586 hectares, located about 30 km from the east of Gachsaran in Kohgiloyeh and Boyer-Ahmad Province and an altitude range between 800 to 3100 meters above the sea level and in a geographical position between the eastern longitude 50˚48ʹ30ʺ to 51˚03ʹ30ʺ and the northern latitude of 30˚22ʹ00ʺ to 30˚34ʹ30ʺ during the years 1394 and 1395 AH (2015 and 2016) through the survey method and linear transects. The results showed that there were 302 species belonging to 208 genera and 64 plant families including one type of Pteridophytes and 301 species of Angiospermes growing in the area. The Asteraceae families with 43, Lamiaceae with 26, Fabaceae with 25, Poaceae with 19, and Apiaceae with 17 species were the biggest Plant families in this region. The results of the study of biological types showed that Therophytes constituted 42%, Hemicryptophytes 31.7%, Cryptophytes 11.5% (Geophytes 11.2% and Helophytes .3%), Phanerophytes 10.5%, and Chamaephytes 3.9% of the biological types of the region and common vegetation elements of Iran-Torani 49% and Iran-Torani common with other regions 42%, Plural region elements 3.6%, Cosmopolitian 2.6%, Nebo-Sindian and the Mediterranean each constituted 1.3% of the vegetative elements of the area. Biological assessment of Plants showed that, in this area, 42 species including one Endangered Species (EN), 2 Vulnerable species (VU), 7 species with Data Deficiency (DD), 32 species with Lower Risk (LR), and 46 species of endemic plants grow in Iran.

In the present research, the flora of Tang-e Khoshk region located in Boyer Ahmad city, Kohgiloyeh Boyer Ahmad province, with an approximate area of 10/000 hectares and an altitude range between 2037 and 2600 meters above sea level and in a geographical position between the eastern longitude 51˚41ʹ to 51˚48ʹ E and the northern latitude of 30˚28ʹ to 30˚30ʹ N have been investigated during the years 1395 and 1396 (2016 and 2017). The sampling techniques of survey and linear transect were used. The results showed that 296 species belonging to 187 plant genera and 56 families grew in this area. From 296 species, one species belonged to the genus Gymnospenrms and 295 species belonged to Angiosperms (44 species from the category of Monocotyledons and 251 species from the category of Dicotyledonds). The families of Asteraceae (with 38 species), Fabaceae (with 28 species), and Lamiaceae (with 23 species) were the most important in this region. The most important genera of the region were Astragalus (with 9 species) and Euphorbia and Centaurea (each with 5 species). Also, most of the geographical elements of the flora were related to the Iran-Turani region (52/3%) and the most important biological forms of plant elements in the region included Hemicryptophytes (44/2%) and Therophytes (33/1%), respectively. The high percentage of Hemicryptophytes indicated the cold and mountainous climate of the region. Based on the results of this study and due to the rich vegetation of the region, the conservation and reproduction of native species in natural habitats or out of natural habitats are emphasized with proper management and conservation.

Abstract Identification of the flora in mining area is necessary for biodiversity conservation as well as vegetation restoration. In this study, flora and functional groups of plants were evaluated in Sungun copper mine, East Azarbayjan province, one of the most important sources of copper in Iran. The vegetation was assessed in the mining area including mine wastes, the area that affected by acid mine drainage and outcrops. The results showed that the greatest number of species and plant families were found in outcrops with 73 species from 21 families. The most frequent plant families were Poaceae (20.55%) and Asteraceae (16.43%). In the area that was affected by acid, mine drainage Astraceae (20.93%) and Poaceae (20.55%) were dominant but in waste dumps the Asteraceae (23.64%) and Fabaceae (14.55%) were the main plant families. Some species were restricted to specific area such as Rhamnus cathartica, Fumaria bracteosa, Equisetum flviatile in acid drainage affected site, Chenopodium album, Atriplex tararica, Hyoscyamus arachnoideus in mine wastes. Carex stenophylla, Hypericum dogonbadanicum and Allium kotschyi were also found to be unique. It was also found that in all three sites the most dominant life forms were hemicryptophytes. There was not any species from phanerophyte in waste dumps. Forbs and perennials were the dominant species of the area and the most of the flora belonged to Iran-Turanian region. We found a potential of species particularly nitrogen fixing species in this area that could be beneficial for vegetation restoration.

Collecting plant specimens and the continuation of this gathering lead to a better understanding of ecosystems, raising awareness about biodiversity and it is criterion for evaluating the genetic erosion over time. Ghalaei-Kashkan covers an area about 30,000 km² and is located in the central Zagros Mountains. Herbarium specimens of the area were collected based on common methods of regional floristic studies during years 1991 to 2013, and named by the Floras of Iran and neighboring countries. In this research, 551 species belonging to 355 genera and 73 families were determined. The chorology of species showed that the highest percentage of the species belonging to the Irano-Turanian region. Permanent Kashkan river caused a strip of the wetland plants have been presented in the northern part of the Ghalaei -Kashkan. Quercus infectoria and Cercis siliquastrum belonging to sub-mountain element that grow in the northern parts. In southern parts of the Ghalaei -Kashkan, particular plant species have been distributed at different altitudes and is divided into Alpine and sub-mountain types. Alpine vegetation type includes mountain Bromegrass, onions (Allium jesdianum), Smyrnium cordifolium, Rheum ribes, and also thorn-cushion vegetations such as: Astragalus spp., Acantholimon spp., Onobrychis spp. and Acanthophyllum spp.. In mountainous type, Oak forests associations are formed. Impact of human on sub-mountain ranges is the main cause of degradation. Genetic erosion in the area implies that the three level of biodiversity: ecosystems, species and populations are under serious threat.