The study of structural and functional characteristics of plant secondary metabolites (PSMs) is a particularly valuable scientific research in relation to recent environmental changes, including those with changing climate or pollutants. The response of plants to ecological changes influences higher plant resource allocation and also PSMs. The accumulation of PSMs in vascular plant tissues is then considered as a common adaptive response of plant to adverse environmental conditions. However, although diverse and complex secondary metabolites produced in the plant kingdom are found in vascular plants, our knowledge of secondary metabolites in ancient terrestrial non-vascular plants is extremely limited. Among them, the Bryophytes or mosses represent an important branch of the plant kingdom with more than 16 000 species playing a fundamental ecological role in many terrestrial ecosystems.

Here we proposed to give a synthesis of chemical interactions of Bryophytes under environmental changes by focusing on some case study under controlled and in situ experiments. As example, living Sphagnum secondary metabolites involved in a peatland plant–soil feedback under environmental changes will be presented. Understanding how environmental changes interact to shape non-vascular plant secondary metabolisms remains an important challenge for chemical ecologists, especially where bryophytes are dominant community members.