مجله بوم شناسی کاربردی
پیاپی 11 (بهار 1394)

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.

This study was undertaken to investigate the role of forest management in tree diversity، regeneration and vegetation in control and managed parcels of series No. 1 of forestry plan in Khalil-Mahale، Behshahr. Thirty samples with an area of 1000 m2 were systematically and randomly taken with a 100 × 75 m grid in both parcels. In each plot، tree number and species type were recorded. In order to study the vegetation، five micro-plots (1 m2)، one in the center and four others in four main directions (half radius from the center of the plot) were taken in each plot. The type and percentage of herbaceous species were recorded in each microplot. To count the regeneration in the center of the main plot، circular sample plots with an area of 100 m2 were used. To study and compare the biodiversity in the two plots and to calculate the richness and evenness، the Simpson and Shannon-Wiener diversity indices، Margalef and Menhinic indices and the Pilo index were used، respectively، using PAST software. The results showed that the number of plant species was more in managed plots. The biodiversity of woody and herbaceous plants richness indices and regeneration of tree species were higher in managed plots. In fact، the results showed that forest management using single selection method had different effects on woody species regeneration and diversity of herbaceous and tree species.

The aim of this study was to investigate the relationship between physical and chemical properties of soils with vegetation distribution in Divan-Darre rangeland as one of the most important rangelands in Kurdistan province. For this purpose، a random systematic 150 m × 200 m gird sampling plan was used to establish 90 sampling plots. In each plot، soil factors and percent cover of each plant species were recorded. The minimal area method was utilized to determine the sample size in the herbaceous layer in this study that it was obtained 4m2. Percent cover of each species was estimated base on the Braun-Blanquet criterion. Vegetation classification was done to determine ecological species group using Cluster method. Ward’s method used to calculate the distance amongst clusters، and Euclidean method for distance index was used. The result of clustering analysis was indicated that four ecological species groups were found. Multivariate analysis was performed to detect the relationship between the physiographic، soil factors and the ecological groups. The most important physiographic and soil factors in these communities were belonged to N، K، OC، OM، pH، SP%، soil texture (clay، sand، and silt)، EC، elevation، aspect and slope. Since each plant species has the specific ecological requirements to soil properties and physiographic factors، study of them can be used to improve vegetation restoration.

Species distribution maps have been widely developed based on ecological niche theory together with statistical and geographical information system in plant ecology. The current study aimed to evaluate Artificial Neural Network (ANN) in mapping potential habitat of Ferula ovina Boiss in Ferydunshar rangelands، Isfahan. This is known as valuable forage and medicinal species. Environmental data (independent variables) and species occurrence data (dependent variable) were required to determine potential habitat of a given species. Some physical and chemical soil properties، climate and physiographic variables were mapped for the entire studied area using krigging and inverse distance weighting methods. F. ovina occurrence data were collected from 278 sites including 137 presence and 141 absence sites. The relationships between the studied environmental variables and F. ovina occurrence data were explored using ANN method. According to the sensitivity analysis، occurrence of F. ovina mostly correlated with silt and sand percentage، elevation slope، and organic matter. Model evaluation based on Kappa coefficient (0. 66) and Receiver operating characteristic (ROC=0. 9) showed good model fitness in relation to reality on local scales. The ANN technique enables managers to identify appropriate areas for rehabilitation practices such as direct seeding and planting.

The present study was conducted to assess effect of dung beetles function on dung removal and seeds dispersion in rangeland of University of Sharekord through completely randomized design in summer. Therefore، the meshes consist of both large and small size was used and filled by goat dung in six treatments (presence of all beetles، absent of the beetles، presence of dwellers and tunnelers، absent of rollers- presence of dwellers، absent of tunnelers and roller- presence of dwellers، presence of small rollers and small tunnelers، absent of large tunnelers and large rollers- Presence of dwellers and small rollers، absent of tunnelers، large rollers) with six replications. In order to assess the ecological function of these insects in the seeds translocation، three sizes of plastic beads used as seed mimics. Results illustrated that the maximum function of the dung beetles was calculated at the investigated possible treatment of presence of dwellers، absent of large tunneler and large roller beetles and، present of small tuneller and small roller beetles. Total of 34. 02% of dungs were removed. The least dung removal was calculated in the control treatment (absent of beetle، 0. 040%) and possible treatment of dwellers، large and small tunellers and، also absent and present of large rollers and small rollers (25. 06%) respectively. Seed removal decreased in the order of: small size (24. 40%) > medium size (3. 73%) > large size (1. 40%). In general، these insects play an important role in the dung removal and secondary seeds dispersal that with regard to the various factors affecting the function of the beetles، further studies would be needed on investigating deeply different seasons and different dung of live stocks feeding on the rangelands.

This research was performed to compare Pb and Cd accumulation in root and leaves of pinus brutia. The effects of these elements in different concentrations (0، 200، 500 and 1000) on the amount of proline، soluble sugar of the plant were also investigated. The experiment was done in a factorial design in three replicates. The concentration of Pb and Cd in leaves and root were measured by atomic absorption. The proline and soluble sugar were measured by Bates and Kochert method، respectively. Results showed that the Pb did not have any effects on poline concentration in pinus brutia. In contrast، Cd increased the amount of proline especially in concentration of 500 ppm. Cd did not affect the amounts of soluble sugar but Pb relatively increased this compound. Accumulation of Cd in root and leaves of the plant increased by increasing Cd and Pb concentration. It is concluded that proline may play a role in Pinus brutia Cd tolerance. Soluble sugar may not play an important role to increase the tolerance of the plant. It is also concluded that for a high Cd accumulation in root، Pinus brutia can be used as a phytostabilization in Cd and Pb polluted soils.

Mapping spatial patterns of potential biodiversity threats is one of the important steps for effective conservation planning and activities. To determine the spatial patterns of threats in Golestan province، 12 criteria in four main groups including structural (fractal coefficient of perimeter، circularity ratio of area، average slope)، compositional aspects of biodiversity (presence of species at risk)، non-biological threats (distance to city، distance to village، distance to road، distance to infrastructure، distance to agricultural land، soil pollution، risk of fire) and isolation (Nearest Neighbor Index) were used. These data layers were digitized in GIS environment and were weighted through Analytical Hierarchy Process. A weighted linear combination was then used to map the spatial pattern of biodiversity threats in the province. Compositional aspect (0. 59)، non-biological threats (0. 23)، isolation (0. 11)، and structural aspect (0. 07) were relatively weighted in the order of importance. Central parts of the province and patches in the northern and southern parts were recognized to be more exposed to biodiversity threats. The central parts of the province were mostly threatened by urban، industrial، road and agricultural development، whereas the northern and southern parts were recognized as areas of conservation importance having a variety of threatened birds.