Grassy biomes—from the steppes of Mongolia to the savannas of Tanzania—are predicted to be the ecosystems hardest hit by the ongoing climate and land use crises. The history of humans has been profoundly intertwined with grassy biomes. Homo evolved in the savannas 2 million years ago (Ma), and agricultural societies arose through the domestication of grasses, such as wheat and barley, 10,000 years ago. These grass crops, as well as corn and rice, remain dominant staple foods globally (1). Livestock production also centers in areas that were once (and sometimes still are) native grasslands. Grassy biomes harbor distinct and diverse sets of plants and animals that have adapted to these environments through millions of years of evolution (2). As the biodiversity and economic prominence of grassy biomes are increasingly being recognized, there is a demand for better understanding of their past and present function to inform policy and management.
Grassy biomes are biogeographically widespread, accounting for >25% of all land on Earth, including 35% of the tropics and subtropics. The emergence of grassy systems during the Cenozoic (the past 66 million years) was complex, shaped by climate, soils, fire, and herbivory in ways that are not fully understood (see the figure). Clarifying these mechanisms will be key for managing the fate of grassy biomes under ongoing and future environmental changes that are driven by human activities.
Read the full Perspective in Science.