Analysis of description and spatial composition of urban green spaces in semi-arid area, using landscape ecology approach (Case Study: Mashhad city)

Urban green spaces as social infrastructures, reduce air pollution, absorb aerosols, adjust temperature, increase relative humidity and mitigate the storms effects, especially in arid and semi-arid areas. Mashhad, with a population of 2,807,464, is the second populous city in Iran. Because of physical development in this city, a vast green space destruction has occurred, which is the opposite of sustainable development model. This study examines the composition and spatial distribution of green spaces and its changes in Mashhad between 1984 and 2013. For this purpose, satellite images of Landsat TM (Landsat 4) and OLI sensors (landsat8) were used. Then, four landscape metrics such as PLAND, AREA, ENN and PD were calculated for different zone of Mashhad. Results showed that during the time period severe destruction were occurred in size and spatial composition and configuration of urban green space in the city. For the meantime, the current urban green space mosaic network has not appropriate extent and unity to provide necessary ecological services to support and improve environmental quality of the city.