Bioacoustics has emerged as a powerful tool for monitoring and understanding ecological and environmental changes. This chapter reviews some applications of bioacoustic monitoring techniques in concert with advanced change detection methodologies for the assessment of biodiversity and ecosystem dynamics. The acoustic environment or soundscape is a reflection of the ecological interactions within an ecosystem and serves as a reliable indicator of environmental health. Change detection in soundscapes due to natural or anthropogenic factors informs changes in species composition, habitat quality, and climate impacts. This chapter also deals with state-of-the-art tools and technologies, from automated recording units and machine learning algorithms to data visualization techniques that have transformed the gathering and processing of acoustic data. Such innovation has now allowed for real-time and long-term monitoring across diverse habitats, from tropical rainforests to urban environments. Additionally, bioacoustic monitoring has proven extremely helpful for studying elusive or nocturnal species and detecting subtle ecosystem changes that might go unnoticed in more traditional methods. Case studies illustrate how bioacoustic monitoring serves to track the impacts of both deforestation and urbanization on animal behavior, as well as the impacts of climate change on behavioral and ecosystem health. Discussed also are challenges associated with data management, technology limitations, and ethical issues, along with strategies overcoming them. Finally, this chapter contemplates a future in which bioacoustics, integrated with interdisciplinary approaches, will be at the epicenter of global conservation efforts and environmentally sustainable management. This comprehensive review on detecting and monitoring bioacoustic change should inspire researchers, conservationists, and policymakers in realizing the potential of sound for understanding and conserving the natural world.