Shown here in a false-colour SPOT satellite image, a section of the River Senegal forms a natural border between the desert sands of Mauritiana (upper right) and the savannah of Senegal (lower left). The Mauritian desert is largely bare rock (grey) and sand dunes (yellow) but some sparse vegetation (Red) does manage to grow along shallow, linear depressions. South of the river are mixed scrub and grassland (a richer red colour), characteristic of savannah vegetation. The main river channel (dark green) meanders along a wide alluvial flood plain (grey), with numerous minor channels and lakes (blue and green), which form when the river bursts its banks.