The unlikely ‘antiquity of Madagascar's grasslands’: Disproportionately forest-limited endemic fauna support anthropogenic transformation from woodland

Abstract

Papers arguing for Malagasy central highlands (MCH) as natural grassland rely disproportionally on a single reference (Bond et al. 2008, The antiquity of Madagascar's grasslands and the rise of C4 grassy biomes. Journal of Biogeography, 35, 1743–1758). The paper argues that (1) evolution of endemic grassland specialist fauna, (2) paleoecological findings and (3) existence of subfossil C4-grazers provide evidence that when humans entered the MCH around 2000 years before present (BP), it was a natural, ancient grassland. Respectfully, we find discrepancies between that study and its sources: (1) proportions of endemic grassland-limited species are 17-fold greater than original data (which show 87% of species are forest-limited and 2% [not 32%] are grassland-limited); (2) paleodata relevant to human-influenced timeframes are omitted; and (3) the hippo specimen used to invoke existence of ancient C4-grazers was the common hippo from mainland Africa, circa 1950. We conclude that the paper's findings are unsupported, and MCH grasslands are likely anthropogenic.