Landscapes Change Dynamics and Patch Connectivity in the Chitwan–Parsa Complex, Nepal

Land-use and land-cover (LULC) changes can lead to various environmental consequences, such as soil degradation, reduced agricultural productivity, flood risks, and the loss and fragmentation of habitats. These alterations not only modify land cover patterns but also disrupt ecological connectivity, affecting species movement, gene flow, and the overall functionality of habitats. This study combines nine spectral indices (NDVI, EVI, GCI, SAVI, BSI, NDWI, MNDWI, NDSAI, and NDBI) and topographic variables (elevation and slope) across the Chitwan–Parsa complex (CPC) for LULC mapping and enhancing accuracy. This study revealed major transitions such as increase in built-up areas from 0.88 % to 3.41 %, increase in grassland from 2.08 % to 7.36 %, decline of cropland from 16.95 % to 8.97 %, decrease in forest cover from 69.07 % to 64.09 %, increase in sand gravel from 6.28 % to 13.19 %, and declined in water bodies from 4.56 % to 2.81 %. This indicates the pressure of urbanization, hydrological stress which reshape the landscape and potentially influencing habitat quality and connectivity in CPC. Furthermore, sixteen core areas are identified across CPC by using core mapper tool. Then, least cost path analysis was done between core habitats to understand habitat dynamics, identify critical corridors, and inform conservation strategies to sustain ecological connectivity. The patches on the eastern side of the complex shows better connectivity than the ones on the western side based on cost values. Patches 5, 6, 7, 8, 9, 10, 12, 14 and 16 emerge as the most connected indicating that they are highly linked to other patches and function as key hubs in the ecological network. The study underscores the need to restore riparian zones and wetlands, protect forest–grassland-water mosaics to sustain key species such as tiger (Panthera tigris), one-horned rhinoceros (Rhinoceros unicornis), elephant (Elephas maximus), and gaur (Bos gaurus).