Madagascar's grassy biomes are ancient and there is much to learn about their ecology and evolution

Abstract

For most of the 20th century, the hypothesis was accepted that Madagascar's extensive grass-dominated ecosystems were of anthropogenic origin, carved out of pristine forests after a mere two millennia of human settlement. We tested an alternative hypothesis that these C4 grassy ecosystems were part of the general Late Miocene expansion of tropical grassy biomes, using diverse data from published sources (Bond et al. 2008). Joseph and Seymour (2021) criticised this paper, which they see as seminal to subsequent studies on the grasslands. Here we respond to their critique of our study. We also briefly note diverse studies since 2008 pointing to the ancient origin of Madagascar's C4 grasses and the ecosystems they dominate. We conclude with key research needs that will help promote open-minded research on these long neglected grassy biomes. The answers would be of considerable scientific and public interest but may also contribute to enlightened management of forest/grassland mosaics.