Ali Asghar Naghipour; Maedeh Sharifi; Ataollah Ebrahimi; Elham Ghesareh Ardestani; Sina Nabizadeh
Abstract
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 ...
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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.
Hamid Jamali; Ataollah Ebrahimi; Elham Ghesareh Ardestani; Fatemeh Pordel
Abstract
Density is an important indicator of vegetation evaluation, which several methods have been developed for its assessment, but their accuracy is concerned. To reveal accuracy of each methods, a study site of 32000-m2 in the steppe rangeland of Marjan, Boroujen was selected and divided into eight macroplots ...
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Density is an important indicator of vegetation evaluation, which several methods have been developed for its assessment, but their accuracy is concerned. To reveal accuracy of each methods, a study site of 32000-m2 in the steppe rangeland of Marjan, Boroujen was selected and divided into eight macroplots of 4000-m2. Then, the individuals of Astragalus verus and Astragalus albispinus were counted in each microplots. A transects of 100-m established parallel to the length of the macroplots (40 × 100 mm) and density was measured using closest individual, nearest neighbor, random pairs, point-centered quarter, third closest individual, angle order and variable area transect methods, systematic-randomly in 10 sampling points in each macroplots. The results indicate that the real density of A. verus and A. albispinus were 0.1593±0.084 and 0.0622±0.0282/m2, respectively. Closest individual (0.1357±0.1315/m2), nearest neighbor (0.1368±0.1432/m2), point-centered quarter (0.1016±0.1664/m2), random pairs (0.0588±0.0536/m2), third closest individual (0.1107±0.0775/m2) and variable area transect (0.0221±0.0105/m2) for A. verus and angle order (0.0927±0.0523/m2), nearest neighbor (0.0424±0.0357/m2) and third closest individual (0.0524±0.0447/m2) for A. albispinus showed no significant difference with controls. The results revealed that the closest estimation to the controls belongs to the nearest neighbor (-0.141) and third closest individual (-0.0098) for A. verus and A. albispinus, respectively. Moreover, the nearest neighbor (RMSE=0.6877, SE=0.0026 and R=0.1147) and closest individual (RMSE=0.5609, SE=0.0007, R=0.0320) showed the most precise estimation of densities of A. verus and A. albispinus, respectively. Generally, the closest individual for estimating plant density of A. verus and the nearest neighbor's for A. albispinus are proposed.