Data from: Palaeo-precipitation is a major determinant of palm species richness patterns across Madagascar: a tropical biodiversity hotspot

The distribution of rainforest in many regions across the Earth was strongly affected by Pleistocene ice ages. However, the extent to which these dynamics are still important for modern-day biodiversity patterns within tropical biodiversity hotspots has not been assessed. We employ a comprehensive dataset of Madagascan palms (Arecaceae) and climate reconstructions from the last glacial maximum (LGM; 21 000 years ago) to assess the relative role of modern environment and LGM climate in explaining geographical species richness patterns in this major tropical biodiversity hotspot. We found that palaeoclimate exerted a strong influence on palm species richness patterns, with richness peaking in areas with higher LGM precipitation relative to present-day even after controlling for modern environment, in particular in northeastern Madagascar, consistent with the persistence of tropical rainforest during the LGM primarily in this region. Our results provide evidence that diversity patterns in the World's most biodiverse regions may be shaped by long-term climate history as well as contemporary environment.

全球诸多区域的热带雨林分布曾深受更新世冰期的强烈影响。然而，这类古气候动态对热带生物多样性热点区域内现代生物多样性格局的持续影响程度，迄今尚未得到评估。本研究借助一套完整的马达加斯加棕榈类（棕榈科Arecaceae）数据集，以及距今21000年的末次冰盛期（Last Glacial Maximum, LGM）气候重建数据，探究现代环境与LGM气候在解释这一核心热带生物多样性热点区域的物种丰富度地理格局时的相对贡献。研究结果显示，古气候对棕榈类物种丰富度格局存在显著影响：即便在控制现代环境变量的条件下，物种丰富度峰值仍集中于LGM时期降水量高于现代的区域，其中以马达加斯加东北部最为突出——这与LGM时期热带雨林主要留存于该区域的现象相符。本研究结果表明，全球生物多样性最为富集的区域，其物种多样性格局或许同时受到长期气候历史与当代环境的共同塑造。