Agricultural heritage has potential significance far beyond its common representation as the “traditional” system of “traditional peoples”. The U.N. Food and Agricultural Organization's Globally Important Agricultural Heritage Systems (GIAHS) program is an important designation that treats heritage agro-ecosystems as living systems, rather than cultural relics. In order for the GIAHS designation to achieve its full potential, however, the role of human knowledge within the continuous cultural and ecological evolution of GIAHS requires much closer examination and appreciation. This paper explores the limits of contemporary nature and cultural conservation, and draws on a coevolutionary theoretical framework in order to better conceptualize the dynamism of such complex agro-ecological systems. In such a view, GIAHS can be seen as evolving systems of sustainable agriculture of great potentail relevance to contemporary society-environment challenges, rather than as relics of the past.