Climate change, land use and other human-driven factors could pit savannas and forests against each other. Without this harmony, the habitats, or biomes, could increasingly encroach on one other to the detriment of the people and animals that rely on them.
Savanna wildfires, combined with climate conditions, maintain the distinct border between savannas and forests in many tropical and subtropical areas. Savanna fires keep tree cover low and prevent forests from encroaching on the grassland. When tree cover is high, as in a forest, fires cannot spread as easily, halting the savanna’s advance into the forest.
But researchers have found that savanna wildfires could be heavily influenced by factors such as climate change, road construction and fire-prevention measures. Less rainfall can result in an uptick in fires that can transform a forest into a savanna, just as breaking up the landscape through road construction and fire control disrupt natural blazes and allow a forest to sprout where there once was a savanna.
Because of these factors, large stretches of South American and African forest and savanna could degenerate into chaotic mutual encroachment.