Anthropogenic transitions from forested to human-dominated landscapes in southern Macaronesia

Human colonization affected forests differently across time

28 February 2022

The impacts of human colonization on oceanic island landscapes vary from prehistory to colonial times.

Modern colonial occupations have often had devastating effects on local ecosystems, particularly on oceanic islands in the tropics and sub-tropics. However, humans also colonized these places in prehistory, but the effects of that early human arrival are complex and less well explored.

Now, a team led by researchers from the University of La Laguna have studied the effects of prehistoric and colonial-era colonization on forests and woodlands by using data from natural sediment deposits in ancient volcanic craters on the Canary Islands and Cabo Verde.

The researchers discovered that these landscapes fluctuated with natural climate change prior to human arrival. Prehistoric colonization was associated with increased evidence of grazing activity, fires and soil erosion. In contrast, recent colonization led to more rapid changes, including significantly more deforestation and forest loss, a rise in introduced plant species, and a drop in native biodiversity (including extinctions of key native tree species).

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References

1. PNAS 118, e2022215118 (2021). doi: 10.1073/pnas.2022215118