A comprehensive understanding of the relationship between land cover, climate change and disturbance dynamics is needed to inform scenarios of vegetation change on the African continent. Although significant advances have been made, large uncertainties exist in projections of future biodiversity and ecosystem change for the world's largest tropical landmass. To better illustrate the effects of climate-disturbance-ecosystem interactions on continental‐scale vegetation change, we apply a novel statistical multivariate envelope approach to subfossil pollen data and climate model outputs (TraCE‐21ka). We target paleoenvironmental records across continental Africa, from the African Humid Period (AHP: ca 14 700-5500 yr BP) - an interval of spatially and temporally variable hydroclimatic conditions - until recent times, to improve our understanding of overarching vegetation trends and to compare changes between forest and grassy biomes (savanna and grassland). Our results suggest that although climate variability was the dominant driver of change, forest and grassy biomes responded asymmetrically: 1) the climatic envelope of grassy biomes expanded, or persisted in increasingly diverse climatic conditions, during the second half of the AHP whilst that of forest did not; 2) forest retreat occurred much more slowly during the mid to late Holocene compared to the early AHP forest expansion; and 3) as forest and grassy biomes diverged during the second half of the AHP, their ecological relationship (envelope overlap) fundamentally changed. Based on these asymmetries and associated changes in human land use, we propose and discuss three hypotheses about the influence of anthropogenic disturbance on continental‐scale vegetation change.

中文翻译：

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整个非洲湿润期森林和草地生物群落对气候变化的不对称响应：受人为干扰的影响？

需要全面了解土地覆盖、气候变化和干扰动态之间的关系，以便为非洲大陆的植被变化情景提供信息。尽管已经取得了重大进展，但对世界上最大的热带陆地未来生物多样性和生态系统变化的预测仍存在很大的不确定性。为了更好地说明气候-干扰-生态系统相互作用对大陆尺度植被变化的影响，我们对亚化石花粉数据和气候模型输出（TraCE-21ka）应用了一种新的统计多元包络方法。我们的目标是整个非洲大陆的古环境记录，从非洲湿润期 (AHP: ca 14 700-5500 yr BP) - 一个空间和时间可变的水文气候条件的区间 - 直到最近，提高我们对总体植被趋势的理解，并比较森林和草地生物群落（稀树草原和草原）之间的变化。我们的研究结果表明，虽然气候变异是变化的主要驱动因素，但森林和草地生物群落的反应不对称：1) 在 AHP 的后半部分，草地生物群落的气候包络扩大，或在日益多样化的气候条件下持续存在，而森林没有; 2) 与早期 AHP 森林扩张相比，全新世中晚期森林退缩发生的速度要慢得多；3）随着森林和草地生物群系在 AHP 的后半段发生分化，它们的生态关系（包络重叠）发生了根本性的变化。基于这些不对称和人类土地利用的相关变化，