Work

Built-Up Land Nearly Triples Along the Islamabad Expressway, Driving Landscape Homogenization (2010–2024)

Year: 2026

Type: article

Abstract: Rapid urbanization along transportation corridors is a key driver of land transformation and landscape homogenization in developing mega-cities. This study analyzes land use and land cover (LULC) change within a 5-km buffer, from Gulberg to T-Chowk, along the Islamabad Expressway, Pakistan, from 2010 to 2024, using multi-temporal Landsat imagery (2010, 2015, 2020, 2024) and landscape metrics. Built-up area increased by 190.8% (51.02 to 148.34 km2) between 2010 and 2024. The expansion is accompanied by sharp declines in vegetation (−36.0%; 89.17 to 57.06 km2), barren land (−93.8%; 63.88 to 3.94 km2), and water bodies (−64.2%; 8.20 to 2.93 km2). All class-area estimates were derived from the R landscapemetrics pipeline and independently verified against visual inspection of the classified rasters, confirming correct class labelling throughout. Landscape structure shifted towards homogenization, with Shannon’s Diversity Index decreasing from 1.19 to 0.74, Patch Density from 74.39 to 21.08 patches per 100 ha, and Edge Density from 219.65 to 99.78 m/ha. LULC maps achieved an accuracy greater than 96% (κ>0.96), it was performed separately for all classified LULC maps ( 2010, 2015, 2020, and 2024) using confusion/error matrices generated from validation samples for each year, and metric estimates showed cross-platform agreement between R and FRAGSTATS within ±5%. These findings indicate rapid corridor-scale consolidation associated with infrastructure-led growth, reducing landscape heterogeneity and potentially weakening ecological resilience. Unlike previous city-scale studies in the Islamabad–Rawalpindi region, this study adopts a transportation-corridor perspective to quantify both land-cover change and ecological fragmentation. The study underscores the necessity for integrated, corridor-scale land-use governance to balance urban expansion with ecosystem sustainability.

Source: Land

DOI: 10.3390/land15081368