Investigating tolerant, adapted and sensitive plant traits to chronological wildfires in a semiarid rangeland

Plant traits can be used to study the mechanism of vegetation responses to the environmental disturbances. This study was aimed to study the changes in plant traits, in six-and two- year periods after wildfires in a semiarid rangeland. Three adjacent sites (control, burnt at 2004, burnt at 2008) were selected in Jowzak rangelands, Northern Khorasan, Iran. Plant sampling was conducted at spring and summer 2010. Floristic list was recorded in each site; also, 58 morphological, phonological and reproductive plant traits were measured. Results indicated four different responses by plant traits to the chronological wildfires. Type1 no response; 37 traits were not affected by the wildfires. Type2 adapted traits: annual plants were increased by times after burning. Type3 tolerant traits: plant with spins, hairs, prostrate canopy, rosette and elongated leaves, ramified stems, scattering by seeds, reproduction by seeds and/or rhizomes, and leaf phenology more than three months initially increased but finally reduced. Type 4 sensitive traits; perennial grasses, shrubs, scopus canopy, non-spiny, succulent leaves and stem elongated leaves gradually decreased with times after burning. In conclusion, plant traits have important roles in determining the responses of plant species to the environmental disturbances; hence, they can affect the secondary succession after the wildfire in rangelands.