Spatial–temporal assessment and modeling of ecological security based on land-use/cover changes (case study: Lavasanat watershed)

Spatial–temporal land-use changes can greatly influence ecosystem services and landscape patterns, which themselves are important factors of ecological security. Spatial–temporal land-use changes can greatly influence ecosystem services and landscape patterns, which themselves are important factors of ecological security. This study analyzed the spatial–temporal changes of land-use/cover in the Lavasanat watershed (Tehran, Iran) between 2000 and 2020 using Landsat satellite images and evaluated the ecological security of the region in terms of landscape metrics and ecosystem services. The spatial–temporal analysis of land-use changes in the 20-year period between 2000 and 2020 showed the substantial growth of the region’s residential areas because of population growth and rising demand for housing and the consequent urban expansion. This analysis also showed a decreasing trend in the total area of agricultural lands in the region. The results suggest that uncontrolled real estate development has greatly affected the ecological structure of the Lavasanat region by breaking the continuity of agricultural lands and replacing the large patches of these lands, which are of great ecological value, with smaller patches, which have far lower ecological value. Also, the results of the InVEST scenario-generator model and the water yield model showed an increase in the water yield of the Lavasanat watershed because of the expansion of built (residential) land-uses, which has led to increased runoff. These changes will have significant environmental consequences such as increased soil erosion, reduced regional groundwater recharge, and easier contaminant displacement, which will undermine the ecological security of the region.