Asghar Farajollahi; Hamidreza Asgari; Majid Ownagh; Mohammadreza Mahboubi; Abolrasoul Salman Mahini
Volume 27, Issue 4 , December 2020, , Pages 682-691
Abstract
In the management of natural resource, recognizing socioeconomic factors affecting land use change is essential for achieving sustainable development and land use planning. In this research, we investigate and determine the socio-economic factors affecting land use changes in the Maraveh Tappeh region ...
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In the management of natural resource, recognizing socioeconomic factors affecting land use change is essential for achieving sustainable development and land use planning. In this research, we investigate and determine the socio-economic factors affecting land use changes in the Maraveh Tappeh region of Golestan province. This area has been affected by land use change in recent years. The rangelands and forests have decreased during the study period (1984-2014), and agricultural use with an annual increase of 132 hectares has reached to 10332.97 ha in 2014. This descriptive-analytic research was carried out in 16 villages in the study area with survey sampling method. Data collection was performed by questionnaire and the numbers of questionnaires were determined 310 people. Sampling was done through a Cochran formula and cluster sampling and multi-stage sampling. Cronbach's alpha coefficient was used to determine the reliability of the study and it was found 0.75. In this study, exploratory factor analysis method was used. For the factor analysis, the principal components method was used using rotation varimax. The results of factor analysis showed that socio-economic factors affect on land-use changes in Maraveh Tappeh region and these factors are including: non-economic efficiency of animal husbandry, Low land per capita for each farmer, rural unemployment, low income and high cost of living, increasing input price, the need for housing and the lack of awareness, social reputation and land ownership. These eight factors explained 63.80% of the total variance. Considering researching findings, attention to economic and financial problems and employment condition of village’s resident of Maraveh Tappeh region is essential. Also, husbandry and livestock production management and supply of livestock inputs have been proposed to reduce the land use changes of forests and rangelands and to protect the natural resources.
Mohsen Yousefi; leila kashi zenouzi
Volume 22, Issue 2 , August 2015, , Pages 240-250
Abstract
The aim of this study was to determine some factors affecting dust storms phenomenon using different methods. In order to determine the best-input combination, variable reduction techniques such as factor analysis (maximum likelihood, principal component analysis), Gama test, and multivariate forward ...
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The aim of this study was to determine some factors affecting dust storms phenomenon using different methods. In order to determine the best-input combination, variable reduction techniques such as factor analysis (maximum likelihood, principal component analysis), Gama test, and multivariate forward regression analysis were used. Each of these methods presented different combinations used by feedforward neural network model, with Levenberg–Marquardt algorithm and multivariate forward regression with R²=0.87 and RMSE=0.04 was selected as the best suitable combination of neural network model. In addition, monthly and seasonal data were applied by neural network using the best-input combination, and the simulation of dust storm phenomenon was done in summer and spring during the months of April, May, June, July, August and September with a higher correlation coefficient and lower mean square error, due to the good distribution of the dust storm data. The results showed that based on these methods used in this study, dominant wind speed, horizontal visibility, continuity and average of wind speed were the most important factors affecting dust storm phenomenon in Yazd province.
Zahra Pakzad; Mahmoud Raeini Sarjaz; Morteza Khodagholi
Volume 20, Issue 1 , June 2013, , Pages 199-212
Abstract
To investigate the effect of climatic factors on distribution of Astragalus adscendens in rangelands of Isfahan province, 57 climatic variables with most importance in terms of ecology of this species were selected. Data were tested by factor analysis in SPSS 16. The maps of Isfahan climatic factors ...
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To investigate the effect of climatic factors on distribution of Astragalus adscendens in rangelands of Isfahan province, 57 climatic variables with most importance in terms of ecology of this species were selected. Data were tested by factor analysis in SPSS 16. The maps of Isfahan climatic factors in the factor analysis were drawn and integrated with the map of vegetation types and digital elevation map to identify the habitat of Astragalus adscendens. According to the results, the first three factors could explain 90.2% of total variance in selected variables as follows: temperature, precipitation, and radiation and wind, with 47.4, 30, and 12.8% of variance, respectively. The three climate factors were compared with the average of climate elements in the habitats of Astragalus adscendens and the areas without this species. Results showed that the areas with an altitude of 2400 m which have approximately 50% relative humidity, with more than 400 mm of rainfall per year and relative radiation are considered as the main habitat for Astragalus adscendens. The tolerance of this species to climatic factors is limited.
Hamid reza Mirdavoodi; Hojat... Zahedi; Masud Shakoei; Javad Tourkan
Volume 13, Issue 3 , February 2006, , Pages 201-211
Abstract
The initial step of each phenomenon is complementary recognizing and understanding of its relationship with other effecting and affecting phenomena. Regarding rangeland vegetation as the first chain of nutrition in rangeland's ecosystems, recognition of its homogeneous areas and vegetation type classification ...
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The initial step of each phenomenon is complementary recognizing and understanding of its relationship with other effecting and affecting phenomena. Regarding rangeland vegetation as the first chain of nutrition in rangeland's ecosystems, recognition of its homogeneous areas and vegetation type classification seems necessary. The present study was carried out in order to determination the most effectiveness ecological factors on vegetation types using Multivariate data analyzing. For that vegetation type was determine of type using GPS together with field survey and drawing map of the areas on the 1/50000 scale. Some data layers for each of vegetation type including density and cover percentage, climate, the mean elevation classes, mean annual rainfall, the mean slop, mean annual temperature, land types and Geographical aspect of the areas were collected and analyzed using Statistica program package and the method of factor analysis. The results of factor analysis shows that between applied variable, three main variables including climate, land types, and Geographic aspect with Eigenvalues of 82.8 are the most effectiveness ecological factors on vegetation types. Using cluster analysis rangelands classified in to 22 groups of Markazi province. the groups were confirm by Discriminate Analysis method.