Abstract Savannas cover large areas of tropical Asia. Yet, these ecosystems are threatened by intense land-use and governmental afforestation initiatives. They are vulnerable to woody encroachment due to fire suppression and climate change. Despite their ancient origins, Asian savannas have been misinterpreted as degraded forest since the colonial period. The consequences of this misinterpretation and climate change on ecosystem functions and diversity of savannas are highly uncertain. We used a dynamic vegetation model, the aDGVM2 to simulate vegetation state under different climate change scenarios to assess how different interpretations of simulated vegetation influence biome patterns in South Asia. Our results show that large areas in South Asia can be interpreted as woodland or degraded forest if we ignore the grassy component and as savanna if the grassy component is considered. The model projects woody encroachment in open savannas due to CO2-fertilization of woody plants and associated biome transitions towards forest by 2099. Our analysis shows that 23.7%–76.6% of the protected areas in the study region are at risk of change. Misclassifying grassy savannas as areas that are suitable for afforestation would lead to a 35–40% loss of these unique ecosystems. A grass-centric biome classification accounting for the grass component in addition to the woody component is necessary to correctly identify Asian savannas. We conclude that there is an urgent need for a correct interpretation of Asian savannas to allow sustainable management and conservation of biodiversity, which is already strongly threatened due to woody encroachment caused by climate change.

中文翻译：

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将亚洲热带稀树草原误解为退化的森林会误导气候变化下的管理和保护政策

摘要 热带稀树草原覆盖了亚洲的大片地区。然而，这些生态系统受到强烈的土地使用和政府植树造林举措的威胁。由于灭火和气候变化，它们很容易受到木质侵蚀。尽管起源古老，但自殖民时期以来，亚洲热带稀树草原一直被误解为退化的森林。这种误解和气候变化对热带草原生态系统功能和多样性的影响是高度不确定的。我们使用动态植被模型 aDGVM2 来模拟不同气候变化情景下的植被状态，以评估对模拟植被的不同解释如何影响南亚的生物群落模式。我们的结果表明，如果我们忽略草地部分，南亚的大片地区可以解释为林地或退化森林，如果考虑草地部分，则可以解释为稀树草原。该模型预测，到 2099 年，由于木本植物的二氧化碳施肥以及相关的生物群落向森林的转变，开放稀树草原的木本侵占。我们的分析表明，研究区域内 23.7% 至 76.6% 的保护区面临变化的风险。将草地稀树草原错误归类为适合植树造林的地区将导致这些独特的生态系统损失 35-40%。以草为中心的生物群落分类除了木本成分外还考虑草成分，这对于正确识别亚洲热带稀树草原是必要的。