فهرست مطالب پژمان طهماسبی کهیانی

Assessment and monitoring of rangeland in different grazing managements seems necessary to manage rangelands. The plant functional groups can be used as appropriate responders for rangelands condition and management. Therefore, this study was performed and aimed to determine the most important traits that are influenced by rangeland variation and management. In order to this, three areas along a grazing gradient including national parks, protected area and free grazing were selected inTangsayad rangelands of Chaharmahal Bakhtiari Province, Iran in 2015. A 100 m transect was established randomly in each site and within it five plots of 4 m2 area at 20 m intervals along transects were determined systematically. Plant species were identified and vegetation cover was recorded in each plot. The number and size of plots and transects were determined regarding to semi-arid rangeland sampling guidelines as well as the dimension of dominant plant species in plant community. Finally, some traits as leaf dimension, plant biomass and cover of species were measured. The results showed that the traits such as leaf length, leaf width, leaf area and leaf weight, grass growth forms and life forms of Hemicryptophyes and Geophytes had significant differences at least in one of three grazing managements sites (P

This study aims to assess the effect of grazing intensity on plant species diversity and functional groups in a highland mountains, Toof sefid watershed, located in 85 km North West of Shahrekord in Charmahal and Bakhtiary province. For sampling, three grazing management area (exclusure, light to moderate grazing, heavy grazing) selected and within each treatment, 300 plots with four square meter were installed along three lines. Shannon diversity indicator, Simpson and species richness and functional groups calculated for each grazing management area and compared using one-way analysis of variance. The results showed all diversity indicators were significantly higher in exclusure (species richness: 14.4, Shannon index: 2.244, and Simpson index: 0.865) compared to light to moderate grazing (species richness: 9.09, Shannon index: 1.377, and Simpson index: 0.617) and heavy grazing (species richness: 10.10, Shannon indicator: 1.536, and Simpson indicator: 0.652). The results indicates that heavy grazing causes reduction only in plant diversity and no changes in functional groups might be occurred in highland; and mountains.

Biomass and carbon sequestration potential is one of the most important benefits of trees in forest ecosystems. This research was done to estimate the amount of biomass in individuals and coppice forms of Quercus brantii Lindl. in Balootboland forests near the Dehdez, Khozestan province. Grid dimensions were selected 100 × 100 m and the nearest tree to a sampling point was chosen. Selected trees should include all diameter classes of high forest or individual trees and all crown diameter classes of coppice if possible. Totally 18 individuals were selected and their quantitative parameters were recorded. Cutting and separating operations were then performed. Different parts of trees were immediately weighted after cutting in the field and sampling was performed to measure the dry weight and the amount of carbon sequestration. According to the results, there was no statistically significant difference between the biomass in two forms of growths. The average biomass of above ground for each tree was approximately determined 277kg and 230kg in form of individual tree and coppice, respectively. These amounts in the stands for individual and coppice forms were estimated 18.2 and 9.3 tons per hectare, respectively. According to the results, large organs (trunk and branches) and small parts (twigs and stump) have more carbon sequestration potential in individual and coppice forms, respectively. The highest and lowest amount of carbon was stored in branches and leaves, respectively.