Effect of heterogeneity of field on natural regeneration of Brant's oak (Quercus brantii Lindl.) using diversity and composition indices of plant species

Brant`s oak (Quercus brantii Lindl.) is one of the most important species of Zagros forest ecosystem that it’s natural regeneration has become a challenge. This study aimed to investigate the composition and species diversity component (alpha, beta and gamma) of indicator plant species in well and poorly seed-origin oak regenerated spots in north of Ilam city. In this study, ten 100-m2 plots were randomly selected from each of the spots. Four sample plots (1 × 1 m) were established in each spot for counting the number of plant species. The Monte Carlo test detected 23 and 13 indicator species from 109 and 58 species in well and poorly seed-origin oak regenerated spots, respectively. Based on Detrended Correspondence Analysis (DCA), two spots were different in terms of species composition. The dominant life forms in the two spots were therophytes and hemicryptophytes. The results showed that different components of species diversity i.e. alpha, beta, and gamma were higher in well seed-origin oak regenerated spots than in poorly regenerated spots. In both spots, diversity within the sample units (alpha) compared with diversity between sample units (beta) had a greater contribution in total diversity (gamma). In general, it can be concluded that the composition and diversity of plant species could be used as a bioindicator for monitoring the heterogeneity of oak regenerated spots.