ﺗﺤﻠﯿﻞ ﺗﻐﯿﯿﺮات ﻓﻀﺎي ﺳﺒﺰ ﺷﻬﺮ ﮔﺮﮔﺎن ﺑﺎ اﺳﺘﻔﺎده از ﻣﺘﺮﯾﮏﻫﺎي ﺳﯿﻤﺎي ﺳﺮزﻣﯿﻦ

Analyzing of Urban Green Space Changes in Gorgan City Using Landscape Metrics

زﻣﯿﻨﻪ و ﻫﺪف: ﺷﻬﺮﻧﺸﯿﻨﯽ ﺳﺮﯾﻊ ﺑﻪﻫﻤﺮاه ﺗﻐﯿﯿﺮات زﯾﺎد در ﭘﻮﺷﺶ اراﺿﯽ، ﺑﺎﻋﺚ اﺧﺘﻼل در ﺳﺎﺧﺘﺎر و ﻋﻤﻠﮑﺮدﻫﺎي زﯾﺴﺖﻣﺤﯿﻄﯽ ﻣﺮﺗﺒﻂ ﺑﺎ ﻓﻀﺎﻫﺎي ﺳﺒﺰ ﺷﻬﺮي ﺷﺪه اﺳﺖ. ﺷﻨﺎﺳﺎﯾﯽ و درك اﯾﻦ ﺗﻐﯿﯿﺮات ﺑﺮاي ﺑﻬﺒﻮد وﺿﻌﯿﺖ در ﻫﺮ ﻣﮑﺎﻧﯽ اﻣﺮي ﻻزم و اﺟﺘﻨﺎب ﻧﺎﭘﺬﯾﺮﻣﯽﺑﺎﺷﺪ. ﺑﺮ ﻫﻤﯿﻦ اﺳﺎس ﻫﺪف از اﯾﻦ ﻣﻄﺎﻟﻌﻪ ﺑﺮرﺳﯽ ﺗﻐﯿﯿﺮات ﻓﻀﺎي ﺳﺒﺰ ﺷﻬﺮ ﮔﺮﮔﺎن ﺑﺎ اﺳﺘﻔﺎده از ﻣﺘﺮﯾﮏﻫﺎي ﺳﯿﻤﺎي ﺳﺮزﻣﯿﻦ و ﺑﻪﮐﺎرﮔﯿﺮي ﺗﮑﻨﯿﮏ-ﻫﺎي ﺳﻨﺠﺶ از دور و ﺳﯿﺴﺘﻢ اﻃﻼﻋﺎت ﺟﻐﺮاﻓﯿﺎﯾﯽ ﻣﯽﺑﺎﺷﺪ. روش ﺑﺮرﺳﯽ: در اﯾﻦ ﭘﮋوﻫﺶ ﺟﻬﺖ ﺗﻬﯿﻪ ﻧﻘﺸﻪﻫﺎي ﮐﺎرﺑﺮي/ﭘﻮﺷﺶ اراﺿﯽ ﺷﻬﺮ ﮔﺮﮔﺎن از ﺗﺼﺎوﯾﺮ ﺳﻨﺠﻨﺪهﻫﺎي ﻣﺎﻫﻮارهﻫﺎي ﻟﻨﺪﺳﺖ ﻣﺘﻌﻠﻖ ﺑﻪ ﺳﺎلﻫﺎي 2001 ،1987 و 2014 اﺳﺘﻔﺎده ﺷﺪه اﺳﺖ. ﺑﻪ ﻃﻮريﮐﻪ ﭘﺲ از اﻧﺠﺎم ﻋﻤﻠﯿﺎت ﭘﯿﺶﭘﺮدازش، ﻃﺒﻘﻪﺑﻨﺪي ﺗﺼﺎوﯾﺮ ﺑﻪ روش ﻃﺒﻘﻪ ﺑﻨﺪي ﻧﻈﺎرت ﺷﺪه ﺑﺎ ﺑﻪ ﮐﺎرﮔﯿﺮي اﻟﮕﻮرﯾﺘﻢ ﺣﺪاﮐﺜﺮ اﺣﺘﻤﺎل اﻧﺠﺎم ﮔﺮﻓﺖ و ﻧﻘﺸﻪﻫﺎي ﻣﻮرد ﻧﻈﺮ در ﺳﻪ ﮐﻼس اراﺿﯽ ﺳﺎﺧﺘﻪ ﺷﺪه، ﻓﻀﺎي ﺳﺒﺰ و ﺳﺎﯾﺮ ﮐﺎرﺑﺮيﻫﺎ ﺗﻬﯿﻪ ﮔﺮدﯾﺪ. ﺳﭙﺲ ﺟﻬﺖ ﺑﺮرﺳﯽ روﻧﺪ ﺗﻐﯿﯿﺮات ﻟﮑﻪﻫﺎي ﺳﺒﺰ ﺷﻬﺮي از ﻣﺘﺮﯾﮏﻫﺎي ﻣﺴﺎﺣﺖ ﻃﺒﻘﻪ، ﺗﻌﺪاد ﻟﮑﻪ، ﻣﯿﺎﻧﮕﯿﻦ اﻧﺪازه ﻟﮑﻪ، ﻣﯿﺎﻧﮕﯿﻦ ﺷﮑﻞ ﻟﮑﻪ و ﺗﺮاﮐﻢ ﺣﺎﺷﯿﻪ اﺳﺘﻔﺎده ﺷﺪ. ﯾﺎﻓﺘﻪﻫﺎ: ﯾﺎﻓﺘﻪﻫﺎي ﺣﺎﺻﻞ از ﺑﺮرﺳﯽ ﺗﻐﯿﯿﺮات زﻣﺎﻧﯽ ﻓﻀﺎي ﺳﺒﺰ ﺷﻬﺮ ﮔﺮﮔﺎن ﻧﺸﺎن داد ﮐﻪ ﺑﯿﻦ ﺳﺎلﻫﺎي 1987 ﺗﺎ 2014 ﻣﻘﺪار زﯾﺎدي از اراﺿﯽ ﺳﺒﺰ ﺑﻪ وﯾﮋه اراﺿﯽ ﮐﺸﺎورزي و ﺟﻨﮕﻠﯽ ﮐﺎﻫﺶ ﯾﺎﻓﺘﻪ و ﺑﺮ ﻣﯿﺰان اراﺿﯽ ﺳﺎﺧﺘﻪ ﺷﺪه اﺿﺎﻓﻪ ﺷﺪه اﺳﺖ. ﺑﻪﻃﻮريﮐﻪ ﻃﯽ اﯾﻦ 27 ﺳﺎل اراﺿﯽ ﺳﺎﺧﺘﻪ ﺷﺪه ﺑﺎ ﻣﯿﺰان 15/86 ﮐﯿﻠﻮﻣﺘﺮﻣﺮﺑﻊ روﻧﺪ اﻓﺰاﯾﺸﯽ و در ﻣﻘﺎﺑﻞ ﻓﻀﺎي ﺳﺒﺰ ﺑﺎ ﻣﻘﺪار 6/53 ﮐﯿﻠﻮﻣﺘﺮ ﻣﺮﺑﻊ روﻧﺪ ﮐﺎﻫﺸﯽ را داﺷﺘﻪ-اﻧﺪ. ﻫﻤﭽﻨﯿﻦ ﺑﺮرﺳﯽ و ﺗﺤﻠﯿﻞ ﻣﺘﺮﯾﮏﻫﺎي ﺳﯿﻤﺎي ﺳﺮزﻣﯿﻦ ﻧﯿﺰ ﺣﺎﮐﯽ از ﮐﺎﻫﺶ ﺗﻌﺪاد و اﻧﺪازه ﻟﮑﻪﻫﺎي ﺳﺒﺰ ﻫﻤﺮاه ﺑﺎ ﺗﮑﻪ ﺗﮑﻪ ﺷﺪن و از ﻫﻢ ﮔﺴﯿﺨﺘﮕﯽ آنﻫﺎ ﻣﯽﺑﺎﺷﺪ. ﺑﺤﺚ و ﻧﺘﯿﺠﻪﮔﯿﺮي: ﻧﺘﺎﯾﺞ ﺣﺎﺻﻞ از ﺑﺮرﺳﯽ روﻧﺪ ﺗﻐﯿﯿﺮات ﭘﻮﺷﺶ اراﺿﯽ ﻃﯽ 27 ﺳﺎل ﻧﺸﺎن داد ﮐﻪ ﻓﻀﺎﻫﺎي ﺳﺒﺰ ﺑﻪ ﻣﯿﺰان ﻗﺎﺑﻞ ﺗﻮﺟﻬﯽ ﻫﻤﺮاه ﺑﺎ ﺗﮑﻪﺗﮑﻪ ﺷﺪن، روﻧﺪ ﮐﺎﻫﺸﯽ را داﺷﺘﻪ اﺳﺖ. ﺑﻨﺎﺑﺮاﯾﻦ ﺑﻪ ﮐﺎرﮔﯿﺮي روﯾﮑﺮدﻫﺎي ﺟﺪﯾﺪ اﮐﻮﻟﻮژﯾﮏ در ﮐﻨﺎر ﺳﺎﯾﺮ روشﻫﺎي ﻣﻄﺎﻟﻌﺎت ﻓﻀﺎﻫﺎي ﺳﺒﺰ در ﺑﺮﻧﺎﻣﻪرﯾﺰيﻫﺎي ﺷﻬﺮي ﺿﺮوري ﻣﯽﺑﺎﺷﺪ.

Background and Objective: Rapid urbanization and vast changes in land cover have disrupted the urban green patches environmental structure and functions. Identifying and understanding these changes is necessary to improve the urban green patches situation in any place. Accordingly, the aim of this study is to evaluate the changes of green patches of Gorgan City using landscape metrics, remote sensing and geographical information system techniques. Method: In this research, Landsat satellite images for 1987, 2001, and 2014 have been used to provide land use/cover maps of Gorgan City. After conducting the preprocessing, classification of the images was done using the supervised method and the maximum likelihood algorithm. Then the maps were reclassified in three classes namely built-up areas, green patches and other land uses. Afterwards, in order to investigate the changes in urban green patches, landscape metrics including Class Area, Number of Patch, Mean Patch Size, Mean Size Index and Edge Density was used. Findings: Findings show that from 1987 to 2014, green patches, especially agricultural and forest lands, has been decreased and built-up areas has been increased. During these 27 years, built-up areas have increased approximately 15/86 km2 and green patches have decreased approximately 6/53 Km2. Also, the analysis of landscape metrics shows a decrease in the number and size of green patches due to fragmentation and disintegration. Discussion and Conclusion: The results of 27 years’ green patches dynamic in Gorgan City show that the green patch of the city has been significantly reduced and fragmented. Therefore, studying urban green patch changes using new ecological approaches and methods, is necessary in any urban planning.