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

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.

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 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.

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.