The Atlantic meridional overturning circulation (AMOC) has caused significant climate changes over the past 90 000 years. Prior work has hypothesized that these millennial-scale climate variations effected past and contemporary biodiversity, but the effects are understudied. Moreover, few biogeographic models have accounted for uncertainties in palaeoclimatic simulations of millennial-scale variability. We examine whether refuges from millennial-scale climate oscillations have left detectable legacies in the patterns of contemporary species richness in eastern North America. We analyse 13 palaeoclimate estimates from climate simulations and proxy-based reconstructions as predictors for the contemporary richness of amphibians, passerine birds, mammals, reptiles and trees. Results suggest that past climate changes owing to AMOC variations have left weak but detectable imprints on the contemporary richness of mammals and trees. High temperature stability, precipitation increase, and an apparent climate fulcrum in the southeastern United States across millennial-scale climate oscillations aligns with high biodiversity in the region. These findings support the hypothesis that the southeastern United States may have acted as a biodiversity refuge. However, for some taxa, the strength and direction of palaeoclimate-richness relationships varies among different palaeoclimate estimates, pointing to the importance of palaeoclimatic ensembles and the need for caution when basing biogeographic interpretations on individual palaeoclimate simulations.

This article is part of the theme issue ‘Ecological novelty and planetary stewardship: biodiversity dynamics in a transforming biosphere’.

过去 9 万年来，大西洋经向翻转环流 (AMOC) 造成了显着的气候变化。先前的工作假设这些千年规模的气候变化影响了过去和当代的生物多样性，但其影响尚未得到充分研究。此外，很少有生物地理学模型能够解释千年尺度变化的古气候模拟中的不确定性。我们研究了千年规模气候波动的避难所是否在北美东部当代物种丰富度模式中留下了可检测的遗产。我们分析了来自气候模拟和基于代理的重建的 13 项古气候估计，作为当代两栖动物、雀形目鸟类、哺乳动物、爬行动物和树木丰富度的预测因子。结果表明，过去由于 AMOC 变化而导致的气候变化对当代哺乳动物和树木的丰富度留下了微弱但可察觉的印记。美国东南部的高温稳定性、降水量增加和明显的气候支点跨越千禧年规模的气候振荡，与该地区的高生物多样性相一致。这些发现支持了美国东南部可能充当生物多样性避难所的假设。然而，对于某些类群，古气候与丰富度关系的强度和方向在不同的古气候估计中有所不同，这表明古气候整体的重要性以及在基于个体古气候模拟进行生物地理解释时需要谨慎。

本文是主题“生态新颖性和行星管理：转型生物圈中的生物多样性动态”的一部分。