Protected areas (PA) have been considered as biodiversity conservation hub across the globe. The conventional “top-down” management approach has been failed to ensure resource sustainability in many PA. Therefore, co-management was introduced to secure the PA of Bangladesh and started with legal framework in 2008 (IPAC Project) until 2018 (CREL Project). Thus, land-use and biodiversity change analysis from a decade before and after 2008 has generated comparison of previous and after scenario of co-management. Hence for evaluating effects of co-management on temporal biodiversity and land-use change in Bangladesh, two PA, Chunati Wildlife Sanctuary (CWS) under IUCN Protected Area Category IV and Lawachara National Park (LNP) under IUCN Protected Area Category II, were selected. Community structure of both vascular plants and avifauna species was used to determine current biodiversity variations with habitat influence. Land-use change analysis revealed deforestation and settlements expansion in CWS but decrease in LNP. Trend analysis forecasted good future of LNP in terms of forest cover till 2038. Biodiversity analysis revealed that CWS is slightly more diverse and even than LNP. Comparative analysis recognized prominent loss of biodiversity before co-management period. Therefore, co-management system can be employed in the rest of reserve-forest areas of Bangladesh for conservation betterment.