Climate change in Europe between 90 and 50 kyr BP and Neanderthal territorial habitability

RESEARCH ARTICLE Climate change in Europe between 90 and 50 kyr BP and Neanderthal territorial habitability Anna DegioanniID1*, Sandrine Cabut1, Silvana Condemi2, Robin S. Smith3 1 Aix-Marseille Universite, CNRS, Minist, Culture, LAMPEA, Aix-en-Provence, France, 2 Aix-Marseille Universite, EFS, CNRS, ADES, Marseille, France, 3 Department of Meteorology, NCAS, University of Reading, Reading, United Kingdom * anna.degioanni@univ-amu.fr Abstract After having lived as the dominant human species in Europe for over 200 kyr, Homo nean- derthalensis (the Neanderthals) disappeared around 40 kyr BP (Before Present) Higham T (2014). Competition with Homo sapiens, who arrived in Europe around the same time, is often invoked to explain this extinction. Others have argued that climate change may have reduced the living space of this population making its disappearance more rapid. In order to test the climate change hypothesis we modelled the Neanderthals’ ecological niches in Europe between 90 and 50 kyr BP through paleoenvironmental reconstructions and Eco- Cultural Niche Modelling. We selected five environmental variables (orographic height, mean annual precipitation, mean temperature of the coldest month, carrying capacity and friction, see below) from climate model simulations of 5 periods between 90 and 50 kyr BP in Europe. We used Structural Similarity (SSIM) index to compare the probability maps of suit- able niches to Neanderthals performed by Maxent. After a strong initial environmental change between the first (P1 = 90 to 83 kyr BP) and second (P2 = 83 to 69 kyr BP) periods,

our results show that large areas highly suitable for Neanderthal occupation persisted across Europe. As our results show an increase/stability of the areas suitable to Neander- thals, the question of the cause of the decrease or displacement of the Neanderthal popula- tion towards southern Europe after this climatic change remains open. Introduction Neanderthals evolved in Europe over a long period. The setup of their features can be followed through the MIS (marine oxygen-isotope stage) 7 and 6. They dominated unchallenged until MIS 3, when Homo sapiens gradually settled in Europe [1]. Around 40 kyr BP, Neanderthals were totally replaced by Homo sapiens [2]. Neanderthals were well-suited to Europe [3], remaining in this region through a succession of major glacial periods characterized by extensive ice sheets and warmer interglacials. They lived in heterogeneous environments extending from temperate grasslands to the tundra biome, indicating a high degree of plasticity in relation to the environment [4]. A plethora of studies (but almost all on Homo sapiens) investigate the effect of climate on human dispersal and evolution [5]. PLOS ONE PLOS ONE | https://doi.org/10.1371/journal.pone.0308690 February 26, 2025 1 / 17 a1111111111 a1111111111 a1111111111 a1111111111 a1111111111 OPEN ACCESS Citation: Degioanni A, Cabut S, Condemi S, Smith RS (2025) Climate change in Europe between 90 and 50 kyr BP and Neanderthal territorial habitability. PLoS ONE 20(2): e0308690. https:// doi.org/10.1371/journal.pone.0308690 Editor: Marco Peresani, Universita degli Studi di Ferrara, ITALY

Received: July 29, 2024 Accepted: January 17, 2025 Published: February 26, 2025 Copyright: © 2025 Degioanni et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. Data Availability Statement: All relevant data are within the manuscript and its Supporting Information files. Funding: The author(s) received no specific funding for this work. Competing interests: The authors have declared that no competing interests exist