Showing 5 results for Gholami
S. Zarekia, M. Fayaz, P. Gholami, M. Goudarzi, F. Jafari ,
Volume 2, Issue 6 (3-2014)
Abstract
Livestock grazing is a common human-induced activity with direct and indirect effects even on the ecosystems of protected areas. The present study analyzed the effects of different grazing management methods on species diversity and richness in the steppe rangelands of Saveh, Iran. Data were collected from sixty 2×2 m plots within the areas of three, four-years protected range management projects. Margalef’s and Menhinick's indices, Simpson and Shannon-Weiner indices, and Pielou's index were used to evaluate plant species richness, diversity, and evenness, respectively. All data analyses were performed in PAST and SPSS. According to the mean values obtained for Shannon-Weiner index, Nemati rangeland (with rest-rotation grazing system and moderate grazing intensity) and Shirali Baglou rangeland (with continuous grazing throughout the year and high grazing intensity) had high species diversity with no significant differences among them. However, Chagneh rangeland (with continuous grazing for six months and fairly high grazing intensity) had the lowest diversity. Low values of diversity indices indicated low species diversity in steppe rangelands. Moreover, Shirali Baglou rangeland had the highest species richness compared to the other sites. In the other three rangelands, both species richness and diversity decreased with increasing the grazing intensity. Despite poor range conditions in Shirali Baglou rangeland, intensive livestock grazing and the consequent rise in invasive species increased species abundance and hence, resulting in species richness and diversity in the area. Although over-grazing throughout the year can promote plant species richness through increasing annual species, consequent soil degradation and instability of rangeland ecosystem can be expected.
Sh. Gholami, A. Salman Mahini, S. M. Hosseini, J. Mohammadi, E. Sayad,
Volume 3, Issue 7 (6-2014)
Abstract
The spatial distribution of soil organisms is influenced by the plant cover, thus resulting in a horizontal mosaic of areas subjected to gradients of nutrient availability and microclimatic conditions.This study was conducted to investigate the spatial variability of soil macrofauna in relation to vegetation density in the riparian forest landscape of Karkhe. The vegetation density was determined by calculating the NDVI index. Soil macrofauna were sampled using 200 sampling points along parallel transects (perpendicular to the river). The maximum distance between samples was 0.5 km. Soil macrofauna were extracted from 50 cm×50 cm×25 cm soil monolith by the hand-sorting procedure. Abundance, diversity (Shannon H’ index), richness (Menhinick index) and evenness (Sheldon index) were calculated. Soil macrofauna and NDVI data were analyzed using geostatistics (variogram) in order to describe and quantify the spatial continuity. The variograms were spherical, revealing the presence of spatial autocorrelation. The range of influence was 1724 m for abundance, 1326 m for diversity, 1825 m for richness, 1450 for evenness and 1977 m for NDVI. The kriging maps showed that the NDVI Index and soil macrofauna had spatial variability. The spatial pattern of soil macrofauna abundance and biodiversity were similar to the spatial pattern of vegetation density as shown in the correlation.
Sh. Gholami , E. Sayad,
Volume 4, Issue 12 (9-2015)
Abstract
In Zagros forest ecosystem, spatial variability of soil and vegetation properties are controlled by series of physical and biological parameters including topographical and anthropogenic factors. Distribution patterns of these properties are greatly variable. In the current study, geostatistics and fractal theory were used to assess the spatial variability of tree canopy and soil bulk density in a part of Zagros forests in Kermanshah province. The spatial structure was investigated by calculating the variogram and fractal dimension. The results showed that none of the variables had a spatial autocorrelation and indeed confirmed the lack of any significant spatial structure. Even though the soil bulk density had an intermediate spatial structure with the exponential model, it is not remarkable and autocorrelation did not show any sign of spatial dependency. The study of distribution and fractal behavior of variables showed an intensive variability in the study area, and spatial variability did not have a remarkable structure. Fractal dimension of both variables also were high. Totally, it seems that as a result of disturbance and pressure effect on this ecosystem spatial dependency of the variables has decreased to the level that they could be accepted independent.
H. Darabi, Sh. Gholami, ,
Volume 5, Issue 18 (2-2017)
Abstract
The regeneration is one of the most important phenomena in forest ecosystems and the most important factor of development and sustainability of forests. Assessment of the regeneration is one of the best criteria for monitoring forest function stability. The aim of this study was to investigate the spatial variability of regeneration diversity and its relationship with tree species diversity in Zagros Forests, Kermanshah (Gahvareh).This study was conducted at 70 hectares of Gahvareh forests. In this area, 67 sample plots (400 m2) were used in a 100 × 100 m sampling grid. In each plot, total number and species of trees and all seedlings which had diameter less than 7.5 cm were recorded. We also recorded asexual regeneration in ¼ plots (100 m2).Then the spatial continuity was described using geostatistics (variogram and cross- variogram). The variograms of variables revealed the presence of spatial autocorrelation except evenness index (Sheldon) of trees and sexual regeneration. They had spatial dependence at large ranges that showed the large distance of dependency and homogeny of condition. In addition, cross-variograms indicated a strong spatial relationship between diversity of sexual regeneration and tree diversity and between diversity and richness of asexual regeneration and tree abundance.
F. Bahmani, A. Soltani, D. Mafi-Gholami,
Volume 11, Issue 1 (5-2022)
Abstract
Do climatic variations and drought magnitude affect large-scale vegetation composition in the Central Zagrosian forests, and to what extent do topographic variables of altitude and aspect play a role in these potential differences? To answer this question, in this research, the flora list of 15 Central Zagros forests was obtained in five plant life forms between the valleys of two rivers, Gerdbisheh and Bazeft, over the distance of 170 km, using 226 half-hectare sample plots. Two-way cluster analysis and multi-reference permutation procedures (MRPP) were used to validate significant differences in plant composition at the landscape level. Subsequently, plant communities were divided into three ecological groups: eastern, central and western. Canonical correspondence analysis (CCA) was used to determine the correlation between changing plant composition and climatic and topographic variables as well as plant life forms. The results showed that forests in the western ecological group are significantly and positively correlated with the De Marton aridity index, while the drought magnitude differentiates the other two ecological groups. Also, altitude had a significant effect on differentiating the eastern and central ecological groups. The main difference between the three ecological groups in terms of plant life forms, was due to the significant correlation of Therophytes, Cryptophytes and Hemicryptophytes with the driest ecological group (eastern). Despite the fact that all the plots were covered with forests, Phanerophytes were not effective in distinguishing ecological groups.
