Historical Olive Agroecosystems of Sicily: Operationalising Biocultural Heritage for Sustainable Futures

Inspired by a vision of agriculture as an ecological practice (agroecology), this thesis provides insights into theoretical approaches and research methods that, when integrated, allow us to investigate the biocultural heritage of historical agroecosystems, with a special focus on olive ( Olea europaea L.) agroecosystems on the island of Sicily. Agroecosystems with deep historical roots offer an incredible research opportunity since they represent ‘long-term experiments in agriculture’ running for millennia, where a wide range of human practices in agriculture is embedded in heterarchical structures of multiple ecological dynamics. By approaching century-old olive trees as living archaeological proxies, their yet undocumented biocultural heritage is documented from three complementary observation points. Following the roots of these trees underground, I trace the memory from plant microfossils (phytoliths) stored in the soil. Walking among them with past and present locals, I tend to cyclical rhythms of entangled plant behaviour and human practices throughout history elucidated by written sources and oral narratives. Observing them from the sky via aerial photographs, the temporal and spatial changes in land use and land organisation are analysed through new geospatial methods. The derived knowledge, when combined, represents a step forward to understand the multi-dimensional causal structures (heterarchies) of historical olive agroecosystems, showing that it is possible to investigate biocultural heritage in a way that knowledge of the past can be operationalised for today´s and future management of these agroecosystems. This can happen only in collaboration with locals who, over the centuries, have worked daily in and with historical agroecosystems, accumulating an alternative, complementary and deep local ecological knowledge on those ecologies. In the final section of the thesis, it is argued that in an agroecology of the long term, biocultural heritage is a bridge between the past and the future of our essential agroecosystems.