Land conversion and climate threaten land birds

These projections are based on the assumption that birds will not dramatically shift their ranges in response to a changing climate, a process that would lessen the range contractions they predict.

While climate change will be the principal driver of range contractions at higher latitudes, their projections reveal that land conversion (e.g., deforestation, conversion of grasslands to croplands, etc.) will have a much larger effect on species that inhabit the tropics. Overall, in the near future, considerably more species may be imperiled by habitat loss because of anthropogenic land conversion rather than climate driven change.

This is because birds in the tropics are especially diverse and tend to have small ranges, making them particularly vulnerable to extinction; whereas birds at higher latitudes are less diverse and tend to have large ranges.

The irony here is that the protection of tropical forests is also one of the strongest buffers against future climate change. A vastly expanded reserve network in the tropics, coupled with more ambitious goals to reduce greenhouse gas emissions and monitor biodiversity impacts, will be needed to minimize global extinctions.