Effect of fire intensity on soil seed bank density of plant functional groups (case study: Golestan national park)

In the current study, the variation of soil seed bank density was evaluated in two different fire severities, i.e. low and high. Soil sampling was done in Sharlegh site, Golestan national park.Therefore, 5 soil samples for both grass patches and shrub patches in each burned and control sited were selected. In burned sited grass and shrub patches were considered as low and high severity fires. For data analysis GLMM and T test were applied.The seed germination method was used in green house to identify soil seeds. Altough, the results of statistical R software indicated that avrage soil seed bank density in burned-site (74.5) had not significant difference compare with unburned-site(132.3), however fire had significant effect on plant functional groups. The results showed that soil seed bank density of different plant functional groups were affected by fire severities, differently. Total seedlings of annual forb was increased (1785to 3543)and decreased (5000to 1471) in low and high fire severities, respectively. Total seedlings of pernnial grasses were significantly decreased(7114 to 842.9) in low fire severity while high fire severity had no significant effect on perennial grasses seed bank density (928 to 1871 ). Fire severity had no significant influence on soil seed bank richness. Our results indicated that the surface and severity of fire should be included and interpreted in the future studies.