What role did fluctuations play in biomass availability for secondary consumers in the disappearance of Neanderthals and the survival of modern humans? To answer this, we quantify the effects of stadial and interstadial conditions on ecosystem productivity and human spatiotemporal distribution patterns during the Middle to Upper Palaeolithic transition (50,000–30,000 calibrated years before the present) in Iberia. First, we used summed probability distribution, optimal linear estimation and Bayesian age modelling to reconstruct an updated timescale for the transition. Next, we executed a generalized dynamic vegetation model to estimate the net primary productivity. Finally, we developed a macroecological model validated with present-day observations to calculate herbivore abundance. The results indicate that, in the Eurosiberian region, the disappearance of Neanderthal groups was contemporaneous with a significant decrease in the available biomass for secondary consumers, and the arrival of the first Homo sapiens populations coincided with an increase in herbivore carrying capacity. During stadials, the Mediterranean region had the most stable conditions and the highest biomass of medium and medium–large herbivores. These outcomes support an ecological cause for the hiatus between the Mousterian and Aurignacian technocomplexes in Northern Iberia and the longer persistence of Neanderthals in southern latitudes.

在尼安德特人的消失和现代人类的生存中，波动对次级消费者的生物量可用性起到了什么作用？为了回答这个问题，我们量化了伊比利亚旧石器时代中期到晚期（距今 50,000-30,000 年校准年）期间，空间和空间条件对生态系统生产力和人类时空分布模式的影响。首先，我们使用求和概率分布、最优线性估计和贝叶斯年龄建模来重建更新的过渡时间尺度。接下来，我们执行了一个广义动态植被模型来估算净初级生产力。最后，我们开发了一个宏观生态模型，该模型已通过当今的观​​察结果进行验证，以计算食草动物的丰度。结果表明，在欧西伯利亚地区，智人种群与食草动物承载能力的增加同时发生。在stadials期间，地中海地区的条件最稳定，中型和中型食草动物的生物量最高。这些结果支持了伊比利亚北部穆斯特和奥里尼亚克技术综合体之间中断的生态原因，以及南纬地区尼安德特人长期存在的原因。