Late Pleistocene-Holocene Iberian small mammal assemblages

Climate and environments have undergone significant changes throughout the Earth’s history, which are reflected in the faunal record. In that sense, small mammals provide valuable palaeoecological insights due to their close relationship with their associated environments. Our research investigates the dynamics of small mammal communities in the Iberian Peninsula from the Late Pleistocene to the Holocene, comparing regional environmental variations as well as anthropogenic impacts. Our review of the small mammal assemblages from 26 archaeological sites across the Iberian Peninsula revealed a differential response of the small mammal communities between the northern and southern areas. The colder climatic conditions which characterized the Late Pleistocene favoured the presence of mid-European species (e.g., Alexandromys (Oecomicrotus) oeconomus, Chionomys (Chionomys) nivalis) in northern regions until the Mid Holocene, while other cold-adapted taxa (e.g., Arvicola amphibius, Microtus gr. (Euarvicola) arvalis, Sorex araneus-coronatus) reached southern regions during the Last Glacial Maximum but disappeared at the beginning of the Holocene period. Palaeoenvironmental reconstructions indicate predominantly open landscapes and colder climates in the Late Pleistocene, with increased forest cover during the Early-Mid Holocene in northern areas. In contrast, the southern regions exhibited more stable environments compared to the northern ones. Our results underscore how the great environmental diversity and interactions between natural and anthropogenic factors affected the composition of Iberian small mammal communities during the last 20,000 years. Most specifically, during the Late Holocene, biogeographical patterns of the small mammals are mostly affected by anthropic activities, with changes in the distribution of some species (Microtus (Iberomys) cabrerae), and the entrance of new ones (synanthropic species).

地球历史上的气候与环境经历了显著变化，这些变化均反映在动物群记录（faunal record）中。就此而言，小型哺乳动物因其与所处环境的紧密关联，可为古生态学（palaeoecological）研究提供极具价值的视角。本研究聚焦晚更新世（Late Pleistocene）至全新世（Holocene）的伊比利亚半岛（Iberian Peninsula）小型哺乳动物群落动态，对比分析区域环境差异及人为影响（anthropogenic impacts）。我们对伊比利亚半岛26处考古遗址（archaeological sites）出土的小型哺乳动物组合（small mammal assemblages）进行了梳理分析，结果显示半岛南北区域的小型哺乳动物群落呈现出差异化响应（differential response）特征。晚更新世以寒冷气候为主要特征，这使得中欧物种（如*Alexandromys (Oecomicrotus) oeconomus*、*Chionomys (Chionomys) nivalis*）在伊比利亚北部地区存续至中全新世；而其他耐寒类群（cold-adapted taxa）（如*Arvicola amphibius*、*Microtus gr. (Euarvicola) arvalis*、*Sorex araneus-coronatus*）在末次盛冰期（Last Glacial Maximum）扩散至南部区域，但在全新世伊始便销声匿迹。古环境重建（Palaeoenvironmental reconstructions）结果表明，晚更新世区域整体以开阔景观与寒冷气候为主，至早-中全新世，北部地区的森林覆盖率显著提升。与之形成鲜明对比的是，南部区域的环境相较于北部更为稳定。本研究结果凸显了过去2万年间，环境多样性以及自然与人为因素的交互作用，如何对伊比利亚半岛小型哺乳动物群落的组成产生影响。尤为关键的是，在晚全新世阶段，小型哺乳动物的生物地理格局（biogeographical patterns）主要受人类活动驱动：部分物种（如*Microtus (Iberomys) cabrerae*）的分布发生改变，同时有新的伴人生物种（synanthropic species）入侵该区域。