جستجوی مقالات مرتبط با کلیدواژه « ارتفاع از سطح دریا » در نشریات گروه « زیست شناسی »

Seed performs a significant role as the most influential factor in the transfer of tree species heritability and forest sustainability. The goal of this study was to examine the effect of altitude from sea level on seed production and regeneration of oriental beech in managed forests. For this purpose, 50 paired sample plots with 2 × 2 m at 1100, 1600 and 2000 m.a.s.l were established. For different experiments were transferred the collected seeds to the seed laboratory. The germinated seeds counted at each sample plot on spring in order to regeneration survey. According to the obtained results, 1600 meters consist of the highest seed, 2000 meters encompass the highest regeneration and 1600 include the un-healthiest seeds. In addition, the maximum seed eaten by insects related to the height of 1600 m. furthermore, 1000 seed weight at the 1100, 1600 and 2000 m were determined to be 207.684, 244.144 and 304.237 grams, respectively. Seed weight appears to be lower in frequently seed years than in regular years. According to the results, the best height for producing and collecting beech seed is at 2000 m.a.s.l. Therefore, the establishment of a seed production station as well as a temporary nursery at this altitude can create a suitable ground for seed reproduction and production in areas of equal height and homogeneity.

Ziziphus nummularia is a thorny shrub belonging to the Rhamnaceae family which has a variety of phytochemical compounds. This study was conducted with the aim of phytochemical and morphological evaluation of Z. nummularia populations in different heights of habitats in Khuzestan province.The leaves and fruits of Z. nummularia were collected from different heights of natural habitats of Khuzestan province, including altitude groups of 0-200, 200-400, 400-800 and 800-1000 meters above sea level in summer and autumn. The morphological characteristics were measured using accurate measuring tools and also phytochemical characteristics were measured using a Spectrophotometer.The results showed that different morphological and phytochemical traits including leaf length, thorn length, ripe fruit weight, ripe fruit diameter, number of thorns, and also content of phenolic compounds, flavonoids, tannins and saponins were significantly different in various habitats of Khuzestan province. Based on the cluster analysis of morphological traits, the trees in habitats with a height of 200-400 m were different from other groups. Principal component analysis (PCA) showed that leaf length and width, saponin and phenol content of leaf and fruit, and leaf tannin content were identified as the most important traits with the highest correlation factor for population identification. Altitude above sea level is an important factor that had a significant impact on various morphological and phytochemical traits of Z. nummularia, including the quality and quantity of leaves and fruits.

This study aimed to investigate the effect of altitude on diversity and Species Importance Value (SIV) of herbaceous species in forests of Kabirkouh, Ilam province. For this purpose, an area of 300 ha was chosen from these forests. The area was divided in to three altitudinal classes (700-1000, 1000-1300, 1300-1600 m a.s.l.). 63 sampling plots were taken in the studied area using the minimal area method. In order to estimate herbaceous cover, the percentage of herbaceous species were recorded according to Van der Marel criterion. Species richness index (R=S), the Shannon- Wiener’s diversity and the Smith- Wilson’s evenness indices were used to calculate the herbaceous species diversity. Determination of correlation between biodiversity indices and altitude was done using Pearson’s correlation coefficient. The results of this study showed that the altitude had a significant effect on the diversity and richness of herbaceous species, and there was a negative correlation between these indices and altitude. The highest species diversity and richness index were in the middle altitudinal class. The results also indicated that altitude had no significant effect on the evenness of herbaceous species. In addition, the shape of the curve of Species Importance Value of herbaceous species in all three altitudinal classes was a lognormal distribution.

The study of flora characteristics and their relationship with ecological factors in habitats has a particular importance, especially in protected areas. This study aims to analyze chorological and endemism of the Central Alborz protected area flora. The study area is the slopes of Welwesht, Dahla, and Azadkouh heights in the protected area of Central Alborz, Mazandaran province. The total number of collected and identified taxa is 331, which belong to 197 genera and 46 families. During the floristic studies of the region, Nepeta azadkouhensis Saberamoli from Lamiaceae family was identified and introduced as a new species. About 49.25% of taxa are hemicryptophytes, 57.40% of all species belong to Irano-Turanian chorotype. Forty-six taxa, equal to 13.9% of all taxa, are endemic to Iran. Of these, 37 species, equal to 82.22% of endemic species, belong to the vegetation zone of Irano-Turanian. The habitat of mountain steppes, mainly with grasses and cushion-shaped plants with 24.47% of the total taxa, has the highest species richness. The results of the species richness study in the altitude classes of the endemic taxa showed that, in total, more than 70% of the taxa are located in medium to semi-high habitats. The study of the presence of endemic species in vegetation elements confirms the dominance of the Irano-Turanian vegetation zone in the region, with the significant presence and influence of European-Siberian elements.

Capers (Capparis spinosa) are one of the valuable medicinal plants that can grow in a wide range of ecological situations. In order to investigate the effect of climate on the physiological compounds of this plant, plant samples were collected in late summer with three replications from the mountainous areas of Amol city (Nemarestaq, Delarestaq and Behrestaq) at four altitudes with a difference of 150 meters (minimum altitude 850 meters). Some physiological traits of leaves and fruits were measured and analyzed by compound analysis in a completely randomized design. Data analysis showed that all the measured traits were affected by climate and were statistically significant, so that the highest amount of chlorophyll a, chlorophyll b, carotenoids, vitamin C, phenol, flavonoids, anthocyanins, antioxidants at an altitude of 1650 meters in Behrestagh region with 6.75, 10.56, 3.59, 15.60, 24.66 mg/g fresh weight, 4.51, 2.55 μmol/g fresh weight and 81.78% inhibition, respectively, and the lowest was observed at an altitude of 850 meters in Nemarstagh area. Regression slope also proved the significant relationship between traits and region and altitude, and antioxidant capacity which is the most important medicinal property of this plant, along with chlorophyll a, had the highest relationship (r² = 0.93). Also, the analysis of Pearson simple correlation coefficients showed a positive and significant effect between the traits. In general, with increasing altitude, an increase in the amount of measured physiological compounds that have medicinal effects was observed, so it is possible to develop the cultivation of some medicinal plants close to this family in the highlands.

Oliveria decumbens Vent is a medicinal plant belongs to the Umbelliferae family. According to the Iran traditional medicine comments this plant is used for the treat of indigestion, diarrhea, relieve fever and infectious diseases. In this research, effects of climate factors, soil and the elevation above sea level were tested on the chemical compounds of O. decumbens. To this, the flowering branches of O. decumbens were taken from 1600-2200 a.s.l. in the Mamassani County in May and air dried. The Clevenger apparatus extraction was used to extract the essence. The chemical compounds were identified using GC and GC/MS and the effect of studied parameters on chemical components were determined. Our result indicated that, there are 13, 16 and 11 chemical compounds in Doshman Ziari, Bavan and Koupen sites, respectively. p-cymene γ-terpinene، thymol and myristicin identified as the main compounds of studied sites. There was significant correlation between the annual precipitation and e elevation above sea level with the essence percentage and chemical compounds of O. decumbens . Furthermore, soil electrical conductivity, acidity and nitrogen had positive significant correlation (p < 0.05) with the percentage of essential oil.

Today, human and wildlife conflict, especially big carnivores such as brown bear, is one of the most challenges and difficulties in biodiversity conservation. Increasing the conflicts have resulted in increasing the negative attitude of local people toward the wildlife and as a result of that leads to increasing poaching of carnivores, especially in an area such as Mazandaran Province which has a high density of human and wildlife. We conducted this study by identifying the area with a high conflicts between the bear and human and human assets in Mazandaran Province. Moreover, we used field observation data to diagnose the distribution of mountainous areas which are potentially exposed to bear attacks in the Province. We collected the bear damages data by questionnaire form and field surveys. Biogeoclimatic variables which were used in the analyses are elevation, distance to the village, the density of beehives, human footprint, the density of domestic animals and land use. We recorded 150 bear attacks to human and human properties which include 16 to human, 19 to domestic animals, 67 and 48 destruction of fruit gardens and beehives, respectively. According to the results, most conflicts are in the spring and autumn. The most important variables are elevation, distance to village and fruit gardens. According to the results, human-bear conflicts in the Mazandaran Province are in the elevation range between 150 to 3000 m. On the other hand, fruit gardens around the villages have a key role in attracting bears to human settlements.

Functional groups are defined as groups of species exhibiting similar responses to an environmental variables. The aim of this study was to investigate the response of plant functional groups to some environmental variables in Mountain forests of southern Zagros (Khuzsetan province- county baghmalek). Vegetation and environmental factors were sampled by 50 circular plots of 1000 m2 selective-randomly along an elevational gradient from 646 to 3172 m a.s.l. sampled vegetation were identified in terms of different growth Forms to woody (tree and shrub), herb and woody seedling (tree and shrub seedling) functional groups and the changes of these functional groups in relation to environmental variables were analyzed using Canonical Correspondence analysis. The results showed that all the functional groups of forest vegetation showed a statistically strong significant correlation with elevation, soil Electrical conductivity, soil available k and soil pH. Also woody functional group showed a correlation with Microbial biomass carbon, clay percentage, Aspect, Organic matter content, sand percentage, slope and Total of nitrogen, herbs showed a correlation with Soil organic matter, soil available p, Total of nitrogen, sand percentage, clay percentage, basal respiration, Bulk density and slope, while woody seedlings showed a correlation with aspect, Total of nitrogen, sand percentage, slope, Microbial biomass carbon and clay percentage. species diversity of woody functional group to 2350 m a.s.l were hight and then above 2350 m a.s.l were low. while herbs were lower diversity at intermediate elevations (1300-1600 m a.s.l) and above 2350 m a.s.l and seedlings had maximum diversity at intermediate elevations.

To evaluate the quantitative and composition status of the trees regeneration in natural forest stands of Astara region, were studied the less disturbed areas in Astara (watershed 1). After selecting the study areaو sampling was done by systematic random method. Sample plots were circle shape with area of 0.1 ha. The relevant data were analyzed in the total altitude classes. The results demonstrated that sapling density of total species and the number of tree regeneration per hectare increased with increasing of altitude from sea level. The results also showed that there are significant correlation between the number of beech, hornbeam and mean total tree regeneration with altitude from sea level. The maximum and minimum number of regeneration were observed at the classes of "tree height

Salinity is a major environmental stresses that Causes severe damage to crops and horticultural crops and also reduce plant biodiversity. Plantation of resistant species is one of the activity to cope on soil and water salinity. Therefore, the identification of salt tolerant species is inevitable. Site conditions of species can affect on plant resistance in the face of environmental stresses. Seeds of four species of wild almond (Amygdalus scoparia, A. arabica, A. elaegnifolia, A. haussknechtii) of three height classes were collected in Karebas site to determine the effect of altitude on the salinity tolerance of wild almond species. Factorial experiment in a completely randomized design with three replications (5 plants per replication) were chosed to determine the salinity torerance of two month almond seedling under salt stress by irrigation with different concentrations of sodium chloride solution whit five leveles (control, 25, 50, 75 and 100 mmol). The results showed that vegetative plant, pigments and plant biomass reducted and accumulation of proline increased by incrising the salt concentration. Amygdalus arabica was resistance species among the four species to salinity. Biomass, growth rate and plant pigments have been decreased and cocentraton of proline have been increased by increasing the altitude. The absorption of copper, zinc, iron, manganese, potassium have been decreased and absorption of magnesium, sodium, chlorine, nitrogen, phosphorus, and calcium increased by Increasing the salinity.

The purpose of this study is determination of best altitude range for forestation of Quercus libani Oliv in Kurdistan province and dendrochronology of this species. For this purpose، twelve disks as a random sampling used from pulled trees on three elevation classes (1400-1600m، 1600-1800m، 1800-2000m) in Marivan forest. ANOVA results showed that diameter growth on these elevation ranges have significant difference (p<0. 05). The average annual increment diameter on first class (1400-1600m) measured about 2. 2mm، second class (1600-1800m) 2. 6mm and third class (1800-2000m) 1. 8mm. Also، results showed that second class site has a better growth condition than other sites. Thus in three sites، average of annual diameter increment in Quercus libani Oliv indicated a direct relationship with precipitation of the last 17 years.

The aim of this study was to identify the various active compounds present in thecapsule of Papaver bracteatum Lindl. belongs to Papaveracaae family and to determine the effect of slope, altitude and soil on these compound's level. To do this, the capsules of 50 plants were collected at before and after capsule maturity stages, in two slopes of 4-10 and >40% and altitudes of 2400-2500 and 2900-3000 m, and soil samples were collected as well. The percentage of active substances was measured by of TLC method, soil texture by hydrometric method, acidity by pH meter and electrical conduction by EC meter. Results showed that soil indices values in both altitudes and slopes did not significantly differ (P 40%) and lower altitude (2400-2500 m).

For achievement to sustainable development and conservation of natural ecosystems and their biodiversity، study on ecological factors and their effects is necessary. Regarding to topographical condition of northern forests of Iran، altitude is an important ecological factor controlling many other dependant variables. In order to، study on this factor 84 sample plots with 400 m2 area were taken by systematic - random sampling method in Sardabrood forests of Chalous. Plant species were identified and their coverage was recorded on the basis of Braun – blanquet scales within every sample plot. Site altitude were divided to five classes including 100 – 400، 400 – 700، 700 – 1000 and 1000 – 1300 m a. s. e. in order to investigate of plant diversity in different altitudinal classes. Heterogeneity indices including Simpson، Reciprocal of Simpson، Shannon and evenness indices including Camargo، Simpson، Smith and Wilson were calculated using Ecological Methodology software. Analysis of variance for heterogeneity and evenness indices showed that the values of these indices had significant differences (P < 0. 01) in different altitudinal classes. The maximum and minimum of heterogeneity indices were founded in fourth and first altitude classes، respectively. The highest value of evenness indices observed in fourth altitude classes and the other classes showed no significant differences. The highest species richness was observed at first altitudinal class and the lowest one was devoted to fourth altitudinal class.

Variation in vegetation of forest gaps predominant by several factors. Unerring، the role of physiographic factors within gaps biodiversity process is very considerable. Hence، the relation of vegetation with physiographic positions was investigated within 59 forest gaps in Fagus forests of Lalis located in Chalous. Elevation range classified in three classes (1100-1200، 1200-1300، and 1300-1400) and slope in five classes (%0-20، %20-40، %40-60، %60-80، %80-100)، also. Aspects quantified by Azimuth، and plant species abundance annotated within gaps. Determination of relation between biodiversity indices and physiographic factors were accomplished by correlation coefficients. Results showed that، differences in mean quantities of biodiversity were significant for increasing of elevation. In survey of slope classes، differences in mean quantities of Simpson، Margalef and Peet indices a strong negatively correlation for the increase of slope، but other indices lacked significant correlation. Also in survey of aspects with differences in mean quantities of Shannon-Wiener، Menhinick، Peet and Camargo indices were significant correlation، and totality northern aspects devoted in most of biodiversity indices quantities.