Palaeoecologists using pollen to map vegetation since the last ice age have noted numerous changes – which they feel increasingly obliged to blame on humans. These changes, such as deforestation or the dominance of certain plants, may happen suddenly or take place over thousands of years. The authors study the pollen record in Colombia, identify plants diagnostic of cultivation or disturbed ground (“degraded vegetation”) and use them to map human activities by proxy. They show how the people move and the landscape changes between 5000 BP and the present day, from the coast inland, and from the lowlands up into the Andes.