title: Savannahs of Asia: antiquity, biogeography, and an uncertain future.
abstract: The savannahs of Asia remain locally unrecognized as distinctive ecosystems, and continue to be viewed as degraded forests or seasonally dry tropical forests. These colonial-era legacies are problematic, because they fail to recognize the unique diversity of Asian savannahs and the critical roles of fire and herbivory in maintaining ecosystem health and diversity. In this review, we show that: the palaeo-historical evidence suggests that the savannahs of Asia have existed for at least 1 million years, long before widespread landscape modification by humans; savannah regions across Asia have levels of C4 grass endemism and diversity that are consistent with area-based expectations for non-Asian savannahs; there are at least three distinct Asian savannah communities, namely deciduous broadleaf savannahs, deciduous fine-leafed and spiny savannahs and evergreen pine savannahs, with distinct functional ecologies consistent with fire- and herbivory-driven community assembly. Via an analysis of savannah climate domains on other continents, we map the potential extent of savannahs across Asia. We find that the climates of African savannahs provide the closest analogues for those of Asian deciduous savannahs, but that Asian pine savannahs occur in climates different to any of the savannahs in the southern continents. Finally, we review major threats to the persistence of savannahs in Asia, including the mismanagement of fire and herbivory, alien woody encroachment, afforestation policies and future climate uncertainty associated with the changing Asian monsoon. Research agendas that target these issues are urgently needed to manage and conserve these ecosystems.This article is part of the themed issue 'Tropical grassy biomes: linking ecology, human use and conservation'.
authors: National Centre for Biological Sciences, Tata Institute of Fundamental Research, GKVK Campus, Bellary Road, Bangalore 560065, India.
authors: Jayashree
authors: 0000-0002-6568-8374
authors: J
authors: Ratnam
authors: Center for Integrative Conservation, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Menglun 666303, Yunnan, People's Republic of China kyle.tomlinson@xtbg.org.cn.
authors: Kyle W
authors: 0000-0003-3039-6766
authors: KW
authors: Tomlinson
authors: National Centre for Biological Sciences, Tata Institute of Fundamental Research, GKVK Campus, Bellary Road, Bangalore 560065, India.
authors: Dina N
authors: 0000-0003-1676-6564
authors: DN
authors: Rasquinha
authors: National Centre for Biological Sciences, Tata Institute of Fundamental Research, GKVK Campus, Bellary Road, Bangalore 560065, India Faculty of Biological Sciences, University of Leeds, Leeds LS2 9JT, UK.
authors: Mahesh
authors: 0000-0002-1661-6542
authors: M
authors: Sankaran
mesh_terms: D001208:Asia; D005390:Fires; D065948:Grassland; D060434:Herbivory
keywords: Asian savannahs; diversity; fire; functional traits; herbivory; tropical dry forest