Volume 16, Issue 2 (8-2022)
مرتع 2022, 16(2): 284-298 |
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Hormozgan Agricultural and Natural Resources Research and Education Center, AREEO, Hormozgan
Abstract: (1528 Views)
Background and purpose: Platychaete aucheri (Boiss.) Boiss., is a bush plant of Asteraceae family. It is one of the exclusive and important species of rangelands in the south of Iran. Geographically it could be seen in Fars, Kerman, Bushehr, and Hormozgan provinces.
This species could be used in desertification control and revived rangelands in the southern regions of Iran. Adaptability of the species in arid environments, resistant to animal grazing, water and wind erosion resilience, bee keeping and traditional medicine use, make it a multi-functional species in desertification projects in the south of Iran.
Materials and methods: Samples were taken in a random-systematic method inside the plots located along the linear transects. 90 plots were used for the three regions of Bastak, Sirmand and Gnu (the main habitats of the species). Topographical factors such as height above sea level, slope steep percentage and geographical direction were determined for each plot. In each of the ecological sites, parameters such as frequency, number of plants, and canopy coverage percentage of each species located inside the plots were measured. Inside each plot, parameters such as bare soil, litter and stones and gravels percentages were also measured. Forage production of Platychaete aucheri was calculated by cutting and weighing inside each plot. Also, in each plot, a soil sample (mixed from 3 soil samples) was collected at the depth of 60 cm. Then physical and chemical characteristics of soil samples were analyzed. In this research, we used Canonical Correspondence Analysis (CCA) and Generalized Additive Model (GAM) for determination of ecological needs of the species with an emphasis on determining the ecological factors affecting vegetation changes and its reply to ecological factors. Data were analyzed in SPSS17 and CANOC4.5 environments. Three main habitats of Platychaete aucheri, Bastak, Sirmand, and Geno, were selected. Vegetation samples were taken is a systematic-random method.
Results: Soil analysis showed that all measured parameters except for soil acidity, were significantly different in habitats (p<0.05). Electrical conductivity, percentage of saturation, and silt were highest in Bastak. Lime and sand were highest in Sirmand. Organic carbon, nitrogen, and clay were highest in Geno. Soil texture was loam and sandy-loam in Bastak, sandy-loam in Sirmand, and sandy-clay-loam in Geno. Total canopy coverage, forage production and number of plants per hectare, litter percentage, and plant height were the highest for Sirmand samples. The highest bare soil percentage was measured in Bastak. The response pattern of Platychaete aucheri along the slope of sand and lime percentage followed the monotonic increase model. With increasing the mentioned values, frequency and percentage of canopy cover were increased too. Adversely, the silt and land slope responses of the species along the slope percentage followed the monotonic decrease model. With increasing the amount of these factors, the frequency and percentage of canopy coverage decreased. The response pattern of the species along the electrical conductivity slope followed the bell model (Unimodal) and its optimal growth limit for this factor was 25 dS/m. The reaction of the plant to sea level and soil moisture followed the Bimodal model. This model indicates the existence of a competitive constraint along the peripheral slope.
Conclusion: The results of this study showed that the frequency and canopy coverage of Platychaete aucheri increased with the increase of slope, sand and lime percentage and declining percentage of silt and slope of the land. The optimal growth situation for this factor was 25 dS/m. The reaction of this plant to sea level and soil moisture followed the Bimodal model. The study of Platychaete aucheri for slope, topography and soil factors, provided valuable information on the ecological needs of this species that can be considered in vegetation management and rangeland improvement operations in similar areas.
This species could be used in desertification control and revived rangelands in the southern regions of Iran. Adaptability of the species in arid environments, resistant to animal grazing, water and wind erosion resilience, bee keeping and traditional medicine use, make it a multi-functional species in desertification projects in the south of Iran.
Materials and methods: Samples were taken in a random-systematic method inside the plots located along the linear transects. 90 plots were used for the three regions of Bastak, Sirmand and Gnu (the main habitats of the species). Topographical factors such as height above sea level, slope steep percentage and geographical direction were determined for each plot. In each of the ecological sites, parameters such as frequency, number of plants, and canopy coverage percentage of each species located inside the plots were measured. Inside each plot, parameters such as bare soil, litter and stones and gravels percentages were also measured. Forage production of Platychaete aucheri was calculated by cutting and weighing inside each plot. Also, in each plot, a soil sample (mixed from 3 soil samples) was collected at the depth of 60 cm. Then physical and chemical characteristics of soil samples were analyzed. In this research, we used Canonical Correspondence Analysis (CCA) and Generalized Additive Model (GAM) for determination of ecological needs of the species with an emphasis on determining the ecological factors affecting vegetation changes and its reply to ecological factors. Data were analyzed in SPSS17 and CANOC4.5 environments. Three main habitats of Platychaete aucheri, Bastak, Sirmand, and Geno, were selected. Vegetation samples were taken is a systematic-random method.
Results: Soil analysis showed that all measured parameters except for soil acidity, were significantly different in habitats (p<0.05). Electrical conductivity, percentage of saturation, and silt were highest in Bastak. Lime and sand were highest in Sirmand. Organic carbon, nitrogen, and clay were highest in Geno. Soil texture was loam and sandy-loam in Bastak, sandy-loam in Sirmand, and sandy-clay-loam in Geno. Total canopy coverage, forage production and number of plants per hectare, litter percentage, and plant height were the highest for Sirmand samples. The highest bare soil percentage was measured in Bastak. The response pattern of Platychaete aucheri along the slope of sand and lime percentage followed the monotonic increase model. With increasing the mentioned values, frequency and percentage of canopy cover were increased too. Adversely, the silt and land slope responses of the species along the slope percentage followed the monotonic decrease model. With increasing the amount of these factors, the frequency and percentage of canopy coverage decreased. The response pattern of the species along the electrical conductivity slope followed the bell model (Unimodal) and its optimal growth limit for this factor was 25 dS/m. The reaction of the plant to sea level and soil moisture followed the Bimodal model. This model indicates the existence of a competitive constraint along the peripheral slope.
Conclusion: The results of this study showed that the frequency and canopy coverage of Platychaete aucheri increased with the increase of slope, sand and lime percentage and declining percentage of silt and slope of the land. The optimal growth situation for this factor was 25 dS/m. The reaction of this plant to sea level and soil moisture followed the Bimodal model. The study of Platychaete aucheri for slope, topography and soil factors, provided valuable information on the ecological needs of this species that can be considered in vegetation management and rangeland improvement operations in similar areas.
Type of Study: Research |
Subject:
Special
Received: 2021/06/1 | Accepted: 2021/12/17 | Published: 2022/08/1
Received: 2021/06/1 | Accepted: 2021/12/17 | Published: 2022/08/1
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