جستجوی مقالات مرتبط با کلیدواژه « physiography » در نشریات گروه « اکولوژی »

The Ferula spp. is one of the most important genus of rangeland plants in the northeastern region of Iran and plays an important role in soil conservation and livelihood of rangeland stockholder. However, improper exploitation and destruction of the plant's habitats are among the factors threatening this natural capital. This study was conducted to identify potential habitats of this genus in the two provinces of Khorasan Razavi and North Khorasan, which can be a step to facilitate and develop replanting and rehabilitation operations of this genus. Spatial data of the presence of this genus with a pixel size of 1100*1100 m were used as actual suitable sites for its growth and layers of environmental information such as climate, soil, geology and physiography were used as predictor variables. First, in Biomapper software version 4, the correlation of prediction variables was examined and important independent variables were selected. The potential habitat map extracted from distribution model mapped using Maxent 3.3 software. The results showed that the model used had good accuracy and reached the AUC of 0.94. In terms of importance. Investigating the input variables to the model using the Jackknife test showed that the variables of the slope, Geology, Soilland, habitat altitude (dem) and the annual average temperature (Bio1) have most important roles in the potential habitat of Ferula spp. In the study area the results of this study can be used to identify the ecological needs of species under study and development and revitalization of its habitats.

The aim of the study was to determine the most important environmental factors (topography, climate, and soil) affecting changes in production and canopy cover of plant variations and to prepare prediction maps, based on the most important factor, in semi-steppe rangelands of Hir-Baghrou, Ardabil province, Iran. First, by detecting the vegetation types and different classes of environmental factors, the production and canopy cover were estimated in 1-m2 plots at full flower stage of dominant species. Then, to determine the most important environmental factors, affecting the production and canopy cover changes, the principal component analysis (PCA) was used. For modeling, first, the correlation between the most effective environmental factors was obtained from the PCA. Then, the highly correlated factors were eliminated and the quadratic polynomial models were obtained. Finally, the obtained models were simulated in GIS. The results of the PCA showed that the first six components with 71.65% had the greatest effect on the production and canopy cover changes. Based on the root mean squared error (RMSE), simulating maps of production (RMSE=0.76) and canopy cover (RMSE=0.48) by effective factor (annual precipitation) showed the highest accuracy. The results of this study can be used to manage the rangelands of Ardabil province to create a balance between supply and demand of production and also to balance carbon.

Rhamnus pallasii is one of the most important and valuable species in Khalkhal forest area. This study aimed to determine the relationship between vegetation properties of Rhamnus pallasii with soil and physiographic factors using PCA analysis in this forest reserve. In so doing, from 1030 to 2250 m.a.s.l, 48 sample plots of square shape with an area of 400 m2, in three land forms (ridge, valley and slope) in four aspects (north, south, east and west) were selectively determined and quantitative characteristics of Rhamnus pallasii such as total height, collar diameter, crown diameter, shoot and regeneration were measured. In addition, in each sample plot, a mixture soil samples were collected from 0 to 30 cm and some of its physical and chemical properties were measured in the laboratory. In order to study the relationship between Rhamnus pallasii distribution and soil characteristics, a survey was done by principal component analysis. The results showed that the distribution range of Buckthorn varies from 1030 to 2250 m.a.s.l. In general, hillsides and valley forms with south -facing hillsides are suitable sites for this species. The highest mean of height (1.74 m), collar diameter (5.65 cm) and crown diameter (1.75 m) on slope land form and number of regeneration in sample plots (7.4) were observed on valley land form. Results from PCA analysis revealed that in the altitude range of 1030 to 2250 m.a.s.l, the soil texture, especially sand% and silt%, OC% and N% were more suitable conditions for the presence and growth of this species in valley and slope forms in the southern aspects area provided. The results of this study can be used to describe ecosystem sustainability as well as conservation and reforestations such as planting with this species and modifying the structure of deforested forests in the studied areas.

The present study was performed to identify diversity indices of herb layer functional groups and its relation to physiographical factors in central Zagros forest, Lorestan. For this purpose, sampling of herbaceous plants was conducted randomly in plots of 2×2 m (n=50) in site. All plants were classified to functional groups including forbs, graminoids and legumes, also Raunkiaerchr('39')s life-forms. Diversity values (Richness, Shanon-weawerchr('39')s diversity and Hillchr('39')s evenness indices) were measured in each plot. Totally, 103 plant species were identified which belong to 27 families and 82 genera. Results indicated that aspect influenced the forbs as well diversity indices of graminoids and legumes, but slope and altitude had no effect on diversity indices. In research site, aspect had important impact on plant distribution and diversity of plant functional groups. Generally, it can be stated that ecological and managemental factors including landuse changes and grazing intensity in Zagros region influenced the plant species composition.

A biodiversity investigation was carried out in the wild pistachio research forest located in southwest of Fars Province between 52˚ 30́́ to 52˚ 40́́ longitude and 29˚ to 29˚ 15́ latitude in an areaof 9374 Ha area. 72 sampling transects fifty meters long were designated using systematic-random design. In each sampling plot a list of bush, shrub, and tree species and their abundance were recorded. The area was divided into 3 slope levels (level 1: >10%., level 2:10%-30%., and level 3: <30 %), 4 aspects levels (north, east, south, and west) and 3 altitudinal levels (level 1: >1,800 m., level 2: 1,800–2,000 m., and level 3: <2,000 m. a.s.l.) using ARC GIS softwear. Data were analyzed using different indices of heterogeneity, richness and evenness by PAST software and were compared in each of the abovedivisions. Gratest heterogeneity and richness indices were observed in area with slope greater than 30%. Results show that the area with 10-30 percent slope has the highest uniformity. Also, indices of heterogeneity and richness showed that north aspect has higher value than the other directions. Evenness indices indicate that the east direction has greater uniformity. Diversity indices among altitudinal levelrevealed that diversity,eveness and richness in altitudes greater than 2000 meter above see level  is more than other altitudinal levels. The results showed that the vegetation diversity of the region are affected by the physiographical condition.

This study aimed to evaluate floristic list, life forms and chorology of plant species of Shalam protected area, which is in western Iran. This region characterized by various physiographic conditions and oak (Quercus brantii L.) as the dominant tree species. Plant species were collected by field survey in May and June 2016. The species were identified and their chorology, growth form and life form were determined using taxonomy resources. The results showed that flora of this region includes 129 plant species, belonging to 34 families and 101 genera. The Poaceae (20 species), Papilionaceae (18 species), Asteraceae (15 species) and Lamiaceae (12 species) were the most frequently encountered families. The number of species was more in the south than in the north-facing slope in different elevation classes. According to Raunkiaer’s classification of life forms, therophytes and hemicryptophytes were the dominant life forms in the study area. In addition, annunal and perennial forbs dominated the growth forms of both facing aspects. In geographical distribution point of view, Irano-turanian and Irano-turanian- Mediterranean in all physiographic conditions had the highest geographical distribution.

In many parts of the world, there is not enough precise information about suitable land for cultivation. Understanding climate and the required parameters during the growth period of crops is the mostimportant factor in the zoning Agroclimate. In Iran, lentils with acreage of 240 thousand hectares and the production of 166 thousand tons per year after the peas in second place is important. Agro-ecological zoning is one of the land evaluating method that can be used to find better lands and improve the planning and management of land resources. The purpose of this research, zoning Agroclimatic Ardabil Province for the cultivation of lentils, In order to identify the characteristics of land resources for the planning and organize and optimal land, Assessing of land suitability, in any of the zone by using AHP is Agroclimatic. Ardabil Province is in northwestern Iran, with an area of 17953 square kilometers, 1.09 percent of the country's total area. The present study was conducted across Ardabil Province which is located in 37° 25' and 39° 42' N latitude and between 47° 03' and 48° 55' E longitude. Data used in this research; climatic factors such as rainfall, temperature, relative humidity, sunshine duration and degree-days during the growing season are the data of 37 synoptic and meteorological and data physiographic such as elevation, slope, aspect, soil and land use map of the study area were collected from relevant organizations. By performing the necessary calculations using SPSS and EXCEL software, the database was frormed in GIS environment. Then for each of the parameters in the GIS environment with generalized point data, linear and polygon surrounding surfaces (Interpolation) were performed, as the data layers and maps. Each of the layers of the study, based on favorable climatic requirements lentils were categorized based on AHP. According to the purpose of this study, the role of the main criteria such as Climate, Soil, Physiography and land use criteria selected under Options AHP were calculated and then using the weighted important factor, weight and final weight of all criteria were determined.
Lentil planting zoning based on climatic factors: Data of climatic elements during the growing season lentils have an influential role. The sudden change of climate data is effective on crop yield. In this study, the rate of climate data based on hierarchical, weight coefficient was determined as follows: Temperature 0.382, precipitation 0.250, humidity 0.160, sunshine hours 0.101, evaporation 0.064 and wind 0.043. By overlaying maps of climatic elements, about 20.42 percent with a very suitable, 37.75 percent was suitable, 24.47 percent average and 17.34 percent of conditions are unsuitable for cultivation of lentils.
Zoning planting lentils, based on physiographic factors: For evaluation the cultivation of lentils, map each datas, elevation, slope and aspect were prepared in GIS environment. Based on the favorable climatic lentils product to physiographic factors, weighting layers were based on AHP. Therefore, the height by a factor of 0.614, slope 0.268 and slope were determined 0.117. By combining maps of physiographic province, 22.68 percent has a very suitable, 21.11 percent sutitable, 17.33 percent average and 38.86 percent conditions are unsuitable for cultivation of lentils.
Zoning lentil cultivation, on the basis of physiographic and climatic elements: By combining all the maps of climatic and physiographic factors that were prepared based on hierarchical method weighting coefficient, the final zoning map Agroclimate lentil cultivation in this province was prepared. Based on the final map, in Ardebil province about 17% very suitable, 32% was suitable, 27% moderately and 24% had poor conditions for the cultivation of lentils. This study aimed to Agroclimateland zoning for planning agriculture in the province of Ardabil. Based on the favorable climate condition for lentil crop, land evaluation of each data was done for production of lentils. So the the main criteria including; climate 0.565 factor, physiographic by a factor of 0.262, soil 0.188 and land the highest weight by a factor of 0.055 respectively has an effective role in the lentils, as well as minimum temperature during the growing season and maximum temperatures and low rainfall (during seed germination and flowering) altitude and the high slope is the limiting factor for the cultivation of lentils in the province.

To investigate the relationship between slope، aspect and elevation and quantitative characteristics of plant species، totally 125 sampling plots were selected in a block systematic design. In each sampling، plot presence، number، height، diameter at breast height (for trees) or root collar (for shrubs) and crown diameters were measured and recorded. Also، we recorded vegetation type according to the portion of species in the plot. Correlation analysis was conducted according to the scale of variables using Pierson، Spearman، Phi and Cramer and Eta coefficients. Results found that elevation is the most important factor affecting presence and density and also type in the study area. Altogether، Atlas Pistach (P. atlantica F. & M) and Wild Almond (A. scoparia Spach.) in low elevations and Maple (A. cinerascens L.)، Marsh-arrow-grass (A. lycioedes Spach.) and mountain almond (A. elaefnifolia Spach.) in higher elevations had better conditions. Slope had a negative correlation with presence of Wild Almond and Send Cherry (Ephedra spp)، and positive correlation with the presence of other species. Also، Wild Pistach trees present in southern aspects showed more basal area and volume in these aspects. Results of this research can be used in the detection of suitable points for development of plant species. Regression analysis showed that frequency of almond and Send Cherry and average height of almond and wild Pistach were predictable according to elevation and slope. Of course، coefficient of determination was low in all cases.

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 Yasouj University. The number of species in each plot and subplot was recorded. The conservation values for different physiographic regions of forest were calculated using integrative parameters such as the number of species per plot, number of rare species per plot, number of tree species per plot, Jaccards similarity coefficient and slope of species-log(area). Comparing the conservation index in different physiographic sites revealed that the areas located in the north, hills and lower altitudes can be considered for in situ conservation due to higher number of trees, rare species and total plant species, species-log (area) slope and lower amount of Jaccard similarity coefficient. But, vegetative sites located in lower slopes and south, because of lower conservation index, can be used for other multipurpose forestry activities. Using this index for different forest areas can be potentially conducted for better conservation and management of Zagros forests.