Abstract: (1221 Views)
Background and objectives: Conservation of endemic species in any region, especially endangered species, is one of the basic management needs and understanding the ecological needs of these species and its relationship with environmental factors is one of the most basic studies in the field of species protection. The purpose of this research is to investigate the ecological factors affecting the distribution of Tamarix androssowii Litv species and to investigate the relationship between soil characteristics and vegetation of different stands of this species in Isfahan province to identifying the biologivcal needs and generalizing to other arid and semiarid areas.
Methodology: In this study, the status of stand of Tamarix androssowii was investigated in four regions of Habibabad, Sejzi, Khara and Shakhkonar in Isfahan province, Iran, according to the patchy distribution of Tamarix spp. in Isfahan province, using the data available in the Department of Natural Resources and watershed of the province. 10 plots (10 x 10 square meters randomly) were considered, in each of the studied areas and also access more accurate data and considering the size of the shrub bases. Soil sampling and vegetation characteristics such as canopy percentage, density and average height of species were recorded in 10 plots. Altitude and slope were recorded in all plots as well. Soil samples were taken at depths of 0-30 and 30-70 cm with 4 repetitions (32 soil samples from 16 profiles) and the parameters of pH, EC, total calcium and magnesium content, SAR, gypsum percentage, TNV, sodium percentage, sand, clay and silt percentage were measured. CANOCO 4.5 and PC-ordination soft wares were used to analyze the relationship between the studied species and environmental factors. Duncan mean comparison test was also used in SPSS 25 software (5 % confidence level).
Results: According to the dendrogram, it can be stated that four studied areas do not differ significantly based on the sampling plots including edaphic factors, and therefore all four sampling areas can be considered as part of one stand for the Tamarix androssowii. The factor of TNV showed an increase in the second depth compared to the first depth due to the high washing. EC, percentage of gypsum, amount of sodium and SAR have shown a decreasing trend. In general, the trend of the factors in two soil depths is the inherent characteristic of these areas, and it generally showed a decreasing trend in the second horizon. Analyzing vegetation data and environmental variables using the PCA method, while providing a graphical interpretation, well revealed the relationships between changes in environmental variables and the distribution of plant species. The highest eigenvalues was belonged to the first two axes of the ranking, and the first and second axis explained a total of 86.7% of the changes. The results showed that the soil texture of this species is mainly sandy loamy. Gypsum percentage was the most effective factor on the density of this species. Moreover, canopy cover percentage and average height of this species were more affected by silt and clay percentage. The study of soil characteristics of stands of this species at two sampling depths showed that the electrical conductivity and the amount of sodium in the first depth were higher than the second depth due to the decomposition of the litter in the surface depth.
Conclusion: In applied studies, vegetation is collected and analyzed to obtain information to solve ecological problems related to the management and protection of natural ecosystems. By knowing the components of natural resources and the relationships between them, it is possible to provide a written and scientific plan to prevent the regression of natural resources, and by generalizing the results in similar areas, it is possible to provide a suitable solution in the field of species protection.
Methodology: In this study, the status of stand of Tamarix androssowii was investigated in four regions of Habibabad, Sejzi, Khara and Shakhkonar in Isfahan province, Iran, according to the patchy distribution of Tamarix spp. in Isfahan province, using the data available in the Department of Natural Resources and watershed of the province. 10 plots (10 x 10 square meters randomly) were considered, in each of the studied areas and also access more accurate data and considering the size of the shrub bases. Soil sampling and vegetation characteristics such as canopy percentage, density and average height of species were recorded in 10 plots. Altitude and slope were recorded in all plots as well. Soil samples were taken at depths of 0-30 and 30-70 cm with 4 repetitions (32 soil samples from 16 profiles) and the parameters of pH, EC, total calcium and magnesium content, SAR, gypsum percentage, TNV, sodium percentage, sand, clay and silt percentage were measured. CANOCO 4.5 and PC-ordination soft wares were used to analyze the relationship between the studied species and environmental factors. Duncan mean comparison test was also used in SPSS 25 software (5 % confidence level).
Results: According to the dendrogram, it can be stated that four studied areas do not differ significantly based on the sampling plots including edaphic factors, and therefore all four sampling areas can be considered as part of one stand for the Tamarix androssowii. The factor of TNV showed an increase in the second depth compared to the first depth due to the high washing. EC, percentage of gypsum, amount of sodium and SAR have shown a decreasing trend. In general, the trend of the factors in two soil depths is the inherent characteristic of these areas, and it generally showed a decreasing trend in the second horizon. Analyzing vegetation data and environmental variables using the PCA method, while providing a graphical interpretation, well revealed the relationships between changes in environmental variables and the distribution of plant species. The highest eigenvalues was belonged to the first two axes of the ranking, and the first and second axis explained a total of 86.7% of the changes. The results showed that the soil texture of this species is mainly sandy loamy. Gypsum percentage was the most effective factor on the density of this species. Moreover, canopy cover percentage and average height of this species were more affected by silt and clay percentage. The study of soil characteristics of stands of this species at two sampling depths showed that the electrical conductivity and the amount of sodium in the first depth were higher than the second depth due to the decomposition of the litter in the surface depth.
Conclusion: In applied studies, vegetation is collected and analyzed to obtain information to solve ecological problems related to the management and protection of natural ecosystems. By knowing the components of natural resources and the relationships between them, it is possible to provide a written and scientific plan to prevent the regression of natural resources, and by generalizing the results in similar areas, it is possible to provide a suitable solution in the field of species protection.
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