Driving force for forest fragmentation explored by land use change in Song watershed, India

Abstract

This study attempts to assess forest fragmentation and degradation in response to land use/land cover changes in Song watershed, India during 1998–2014. Landsat TM and Landsat 8 OLI satellite data across two dates (1998 and 2014) were used to analyze land use/land cover change and its impact on forest cover. The extent of forest degradation was analyzed using fragmentation model. Four categories of disturbance viz. core, perforated, edge and patch were obtained using 200 meters edge width. The result shows overall decrease of 7% in area under forest over 16 years. Area under open forest, mixed land use/land cover I (agriculture, forest and built up) and mixed land use/land cover III (agriculture and built up) has significantly increased while area under dense forest has decreased during the study period. Fragmentation model revealed lots of disturbance in forest located in mixed land use/land cover areas. Perforated and patch classes of forest have experienced a significant increase in their respective areas while core area has decreased at the expense of other fragmentation classes. Degradation of forest occurred at large scale at Hrishikesh and Thano forest ranges of Dehradun district and Gadol range in Tehri Garhwal district lying in the watershed. Rishikesh city in Dehradun district located in southern part of watershed recorded increase in patches due to developmental activities. Remote sensing and fragmentation model showed their effectiveness in analyzing forest degradation and monitoring the health of the forest in the watershed.