Land use change detection in the limestone exploitation area of Margalla Hills National Park (MHNP), Islamabad, Pakistan using geo-spatial techniques

The aim of the study is to assess the limestone (LS) exploitation area and its negative impacts on natural resources using geo-spatial techniques. LS is an important constituent of cement manufacturing which is extensively used in the construction of infrastructure such as roads and buildings. The Margalla Hills National Park (MHNP) is situated around Islamabad and contains a large amount of LS reserves. However, the exploitation of LS from the MHNP is causing harmful environmental impacts on the surrounding areas. Geographic Information System (GIS) and Remote Sensing (RS) have been proved as powerful tools for LS exploitation assessment. Four Landsat Thematic Mapper (TM)/Enhanced Thematic Mapper (ETM+) satellite images have been acquired over a span of 17 years (1992-2009). The temporal changes in the study area were detected by performing the digital image processing techniques of image enhancement and supervised classification. The classification accuracy has been verified with high resolution Google Earth images and by using error matrix. Advanced Space borne Thermal Emission and Reflection Radiometer (ASTER) Global Digital Elevation (GDEM) has been used for topographic information extraction. It was observed that LS exploitation area increased from 0.35% to 5.72% from 1992-2009, whereas, the vegetation was decreased from 23.46% to 12.12%. Urban development also increased rapidly. The results showed that LS exploitation is deteriorating the ecosystem, biodiversity, landscape and vegetation of the MHNP which was established in 1980 to protect, conserve and manage the biodiversity and ecosystem in this region. We conclude that the LS exploitation in the MHNP should be managed properly to secure the water, soil, air quality in the federal capital. Initiatives should be taken for the rehabilitation of the LS exploited areas and then, to suggest alternative LS exploitation sites in the near periphery of study area with EIA restrictions.