Germination response of annual and perennial herbaceous species to fire products in semi-steppe rangelands

Fire is one of the important ecological factors that affect the dynamics of rangeland vegetation. In recent decades, the incidence of wildfires in semi-steppe rangelands has increased significantly, challenging the adaptive capacity of plants for post-fire regeneration. In the present study, the germination response of eight annual and perennial herbaceous species of semi-steppe rangelands of Chaharmahal va Bakhtiari province to fire products treatments including heat (60, 80 and 100° C), smoke, ash, and the combined effect of heat and smoke treatments were investigated. Also, percentage cover change of studied species, one year after the fire were measured in the field. The results showed that the germination of seeds of eight studied plant species showed a significant positive or negative reaction to at least one of the fire product treatments. Combined treatment of smoke and 60° C caused a significant increase in the mean germination percentage of Heteranthelium piliferum. This treatment also significantly reduced the mean germination time of Cousinia cylindracea. Ash treatment also increased the mean germination percentage of Alyssum linifolium and Stachys lavandulifolia. Vegetation sampling results also showed that among the eight species studied, H. piliferum and Taeniatherum crinitum were fire adapted and six species were tolerant. The results of this study can be used as a potential factor to understand the dynamics of vegetation and restoration of degraded rangelands.