Routes of Interaction – Research on pre-modern route-setting, pedogenic and geomorphic effects of trampling, and feedback mechanisms between pathways and gully erosion in the Northern Ethiopian Highlands (Tigray)

In order to investigate the interaction between different human societies and their effect on the natural environment, we focus on three main questions. 1: Where were historical settlements located? 2: Where have the routes connected these settlements passed? 3: How have both these settlements and routes interacted with local pedological and geomorphological processes? The northern Ethiopian Highlands (Tigray) have a documented settlement history spanning at least the last three millennia. Some sites have a centuries- or even millennia-long settlement continuity and the reconstruction of their entanglement can help to learn about the interaction between past societies. Pathways, be it over long- or short distances, provide the potential to investigate past and present decision-making processes in route planning. Furthermore, pathways are an impressive example of human-environment interactions. These pedogeomorphological expressions of human trampling on the same piece of land over a certain period of time have different soil characteristics (soil compaction, pedogenic iron contents) than adjacent land areas and can influence the surface hydrology. Under certain conditions in hilly terrain, pathways can either stabilize or destabilize the landscape, depending on their orientation with regard to the local hydrological network, and their degree of incision into the surface (holloways). As such, we analyzed geomorphic and pedogenic properties of pathways as well as feedback mechanisms between pathways and gully erosion, and how these may influence route planning. The reconstruction of historical routes in northern Ethiopia using a combined approach of geolocating historical travel reports and historical maps dating back to the 15^th century as input data for least-cost-path analyses, have the potential to reveal points of interest for further archaeological research.