The relationship between the diversity of plant species and environmental factors in Vezg region of Yasouj

The diversity is one of the most important issues in ecological studies, especially in vegetation ecology. This research aims to study plant biodiversity in relation to environmental factors survived in the southeast of Yasouj which is the central forests of Zagros ecosystem.

For this purpose, a region with an area of 308 hectares was selected. Then, 61 plots (15×30 m) and 305 microplots (0.5×2 m) were established using random-systematic sampling method. The plots dimensions were also determined using minimal area method. To evaluate the diversity of plant species the most commonly diversity indices was used. Then, one-way ANOVA was used to examine differences in various classes.

Results showed that elevation factor had a strong effect on species diversity and evenness as higher altitude showed higher amount of diversity and evenness. Aspect had significant effect on richness and marked the highest in the northeast. The results also showed that diversity and evenness were affected by slope and they are higher in 51-70 % of slopes. Also, the results indicated that there was a correlation between biodiversity indices with soil properties such as N, Silt and C/N ratio.

Overall, the results of this research in the region showed that, physiographic factors (altitude, slope and aspect) with soil properties always play a decisive role in the pattern of changes in plant biodiversity. So, of many studies carried out in this subject in Zagros forests, this is a very good one to achieve optimal management.