The recent studies reported that more trees in open ecosystems like savannahs and grasslands have substantially reduced the number of native grassland birds.
In the African Savannah in particular, the population of grassland birds has declined by more than 20%.
Grasslands and savannahs cover nearly 40% of the earth’s total landmass, and are home to many endemic and at-risk species of plants and animals.
The cover of grassland habitats had shrunk by 34% while tree cover in these places had increased by 8.7%.
A higher concentration of carbon dioxide in the air due to ongoing climate change also encourages deep-rooted woody plants in grasslands to proliferate.
Increased atmospheric CO2 is likely to promote trees over grasses because the C3 photosynthetic pathway used by trees is favoured under high CO2 conditions.
Once trees become dominant in a system, they may further suppress grasses through shading and fire suppression.