Understanding relationships between people and nature is at the heart of future environmental and economic sustainability. However, interactions between social and community heritage and nature (biodiversity) conservation have remained peripheral to many discussions. With emerging ideas like rewilding, which would restore natural communities across landscapes and engage humans settlements in the process, it is vital that scientists, policy-makers and other stakeholders have clear and accepted definitions set within effective conceptual frameworks. Surprisingly at the interface of ecology and heritage there has been only limited agreement about these matters, which are central to developing future policies, strategies, and even research programmes to address the challenges of future sustainability. In order to present effective, over-arching concepts that bring together aspects of nature (ecology, biodiversity, nature conservation), and heritage (history, socio-economics, ethnology, community, people), we need to explore the development of concepts and policies in both fields. Essentially, there has been a growing awareness in recent decades of the relevance of history and heritage to understanding ecology and biodiversity and the interdependency of the two aspects of the environment. With catastrophic declines in many species on the one hand, and the emergence of radical concepts such as rewilding on the other, it is timely for the two core strands of conservation to be brought together. This paper presents the evolution of approaches and definitions on biocultural diversity to help inform future debates on these challenges, especially in intergovernmental debates where much confusion has existed. We develop concepts of biocultural assets and heritage, biocultural diversity, and eco-cultural landscapes. As traditional cultures morph into urban and industrially globalised ones, we set the debate in the context of ‘cultural severance’ as the separation of people from nature.