Analysis of ground vegetation of Zagros forests using monitoring plots

This research measured and analyzed forest ground vegetation in permanent plots of typical and exclosure areas in the Zagros provinces, providing the possibility for long-term monitoring of quantitative and qualitative changes in vegetation. In total, 30 one-hectare square sample plots and 600 one-meter square microplots were studied along the Zagros, with floristic and environmental data related to tree and forest floor measured and recorded. According to the results, 370 species were identified in the ground vegetation and 20 species of phanerophytes. The most abundant families in exclosure and typical sites were Asteraceae and Poaceae, respectively. Sixty-six percent of the ground vegetation population belonged to the Poaceae family, with the most populated genus being Bromus, comprising 25% of all plant individuals. The largest genus was Astragalus (with 18 species), and its population was about 2.5 times higher in exclosure sites than in typical sites. The average percentage of ground cover (51.2%) and litter cover (34.3%) in exclosure plots was significantly higher than in typical plots (37.6% for ground cover and 25.2% for litter cover). The number of phanerophyte species in the exclosure area was significantly greater than in the typical area, while the difference for other life forms was insignificant. The comparison of diversity indices for ground species in the exclosure and typical plots showed no significant difference between these two groups. In general, the relative protection implemented in some parts of the Zagros, although it did not affect ground species diversity indices, did affect ground vegetation cover, litter cover, species composition, and phanerophyte species.