Fig. 1

Map of the Great Lakes region showing sampling sites and their altitudes in the four agro-ecological zones of DRC and Burundi. Sampling sites located in the lowlands are indicated by squares (AEZ1: altitude < 1200 m), while circles indicate the sampling locations in midlands (AEZ2: altitude 1200–1800 m); and triangles denote sites located in the highlands (AEZ3: altitude 1600–2800 m)