22 Grasslands
Rosen
It took ages for grasses to grow in numbers that might constitute a grassland. And grasslands only started to occupy serious real estate in the past 10 million years—basically yesterday. They now cover roughly one-third of Earth’s land area.
Grasslands rank among the most imperiled and least protected biomes on Earth. They are disappearing even faster than forests, and much of what remains has suffered varying degrees of damage.
The tendency to overlook and undervalue grasslands is a product of their reputation as degraded and thus disposable landscapes—a misperception rooted in centuries of scientific confusion and cultural bias. It reflects a deeply held preference for forests, mainly among people of European descent, that has warped global grassland science and policy.
Veldman proposed the term old-growth grassland to differentiate ancient, intact grasslands from those that form after humans clear a forest or abandon farmland.
Grasses prevail when, for one reason or another, conditions are inhospitable to trees; trees prevail when they grow dense enough to shade out grasses. In many places, grasslands and forests coexist in a slow-motion tug-of-war.
Across Africa, French foresters diagnosed naturally treeless landscapes as severely deforested and colonial governments seized control of the land from locals in the name of restoration. In Madagascar, a former French colony, it’s taken centuries to overturn the narrative of human destruction. “We’ve been told from primary school that Madagascar was covered in forests,” Cédrique Solofondranohatra, a Malagasy botanist, says. Then, supposedly, people came, cut down the trees, and set fire to the landscape, creating vast, artificial grasslands that few scientists even bothered to study. Over the past 15 years, however, work by Solofondranohatra, Bond, and others has uncovered evidence that grassy ecosystems existed on the island long before humans arrived.
Grasslands store less carbon per acre than forests, on average, but in a volatile climate, they can often store it longer.