Data from: Savannahs of Asia: evidence for antiquity, biogeography and an uncertain future

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 extant 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 Hemisphere. 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.

亚洲稀树草原（savannahs）在当地尚未被认定为独特的生态系统，仍被视为退化森林或季节性干燥热带森林。这些殖民时代遗留的认知误区存在诸多问题，因为它们未能认识到亚洲稀树草原的独特多样性，以及火与植食作用在维持生态系统健康与生物多样性中的关键作用。在本综述中，我们的研究结果表明：古历史证据显示，亚洲稀树草原至少已存在100万年，远早于人类大规模改造景观的时期；全亚洲的稀树草原区域的C4草本植物（C4 grass）特有性与多样性水平，符合非亚洲稀树草原基于面积的预期标准；亚洲至少存在三类独特的稀树草原群落，分别为落叶阔叶稀树草原、落叶细叶多刺稀树草原以及常绿松林稀树草原，其功能生态特征均符合火与植食作用驱动的群落组装规律。通过对其他大洲稀树草原气候域的分析，我们绘制了亚洲稀树草原的潜在分布范围。我们发现，非洲稀树草原的气候与亚洲落叶稀树草原的气候最为相似，但亚洲松林稀树草原所处的气候与南半球所有稀树草原的气候均不相同。最后，我们梳理了威胁亚洲稀树草原存续的主要因素，包括火与植食作用管理失当、外来木本植物入侵、造林政策，以及与亚洲季风变化相关的未来气候不确定性。亟需针对上述问题制定研究议程，以实现对这些生态系统的管理与保护。