To understand the resilience of African savannas to global change, quantitative information on the long-term dynamics of vegetation is required. Past dynamics can be reconstructed with the REVEALS model, which requires pollen productivity estimates (PPE) that are calibrated using surface pollen and vegetation data. Here we calculated PPE values for five savanna taxa using the extended R-value (ERV) model and two pollen dispersal options: the Gaussian plume model (GPM) and the Lagrangian stochastic model (LSM). The ERV calculations failed to produce a reliable PPE for Poaceae. We therefore used Combretaceae as the reference taxon – although values obtained with Poaceae as the reference taxon are presented in the supplement. Our results indicate that Combretaceae is the taxon with the highest pollen productivity and Grewia the taxon with the lowest productivity. Acacia and Dichrostachys are intermediate pollen producers. We find no clear indication of whether the GPM PPEs or the LSM PPEs are more realistic, but the differences between these values confirmed that the pollen fall speed has a greater effect in the modelling of GPM than in the LSM. We also applied REVEALS to the pollen record of Lake Otjikoto (northern Namibia) and obtained the first quantitative reconstruction of the last 130 years of vegetation history in the region. Cover estimates for Poaceae indicate the predominance of a semi-open landscape throughout the 20th century, while cover values below 50% since the 21st century correspond to a thick savanna. This change in grass cover is associated with the spread of Vachellia, Senegalia and Grewia reflecting an encroached state.

为了了解非洲大草原对全球变化的适应力，需要有关植被长期动态的定量信息。可以使用REVEALS模型重建过去的动力学，该模型需要使用表面花粉和植被数据校准的花粉生产力估算（PPE）。在这里，我们使用扩展的R值（ERV）模型和两个花粉扩散选项（高斯羽流模型（GPM）和拉格朗日随机模型（LSM））计算了五个热带稀树草原类群的PPE值。ERV计算未能为禾本科提供可靠的PPE。因此，尽管补品中给出了以禾本科作为参考分类单元的值，但我们还是以Combretaceae作为参考分类单元。我们的结果表明，Combretaceae是花粉生产力和Grewia最高的分类单元生产率最低的分类单元。金合欢和Dichrostachy s是中间花粉生产者。我们没有明确表明GPM PPE或LSM PPE是更现实的，但是这些值之间的差异证实了花粉落下速度对GPM的建模比对LSM的影响更大。我们还将REVEALS应用于奥奇科托湖（纳米比亚北部）的花粉记录，并获得了该地区过去130年植被历史的首次定量重建。禾本科的覆盖率估计值表明整个20世纪半开放的景观占主导地位，而21世纪以来覆盖率低于50％的植被代表着稀疏的稀树草原。草皮的这种变化与Vachellia，Senegalia和Grewia反映了一个被侵犯的国家。