Habitat suitability and the genetic structure of human populations during the Last Glacial Maximum (LGM) in Western Europe

Abstract

Human populations in Western Europe during the Last Glacial Maximum were geographically constrained to glacial refugia by the severity of the climate and ecological risk factors. In this research we use an agent-based model of human mobility and interaction, based on ethnographic and archaeological data, to explore the impact of ecological risk on human population structure via a reconstructed landscape of habitat suitability. The agent-based model allows us to evaluate the size and location of glacial refugia, the size of the populations occupying them and the degree of genetic relatedness between people occupying these areas. To do this, we model the probability of an agent foraging groups’ survival as a function of habitat suitability. The model’s simulated “genomes” (composed of regionally specific genetic markers) allow us to track long-term trends of inter-regional interaction and mobility. The results agree with previous archaeological studies situating a large glacial refugium spanning southern France and northeastern Spain, but we expand on those studies by demonstrating that higher rates of population growth in this central refugium led to continuous out-migration and therefore genetic homogeneity across Western Europe, with the possible exception of the Italian peninsula. These results concur with material culture data from known archaeological sites dating to the Last Glacial Maximum and make predictions for future ancient DNA studies.

A new bias-correction method for precipitation over complex terrain suitable for different climate states: a case study using WRF (version 3.8.1)

“…glacial times. This is particularly important for studies where absolute values of precipitation are essential, such as glacier and ice sheet modelling (Seguinot et al, 2014;Jouvet et al, 2017;Jouvet and Huss, 2019), and the assessment of human behaviour during glacial times (Burke et al, 2017;Wren and Burke, 2019). To illustrate the performance of the new method, two regional climate model simulations are performed with WRF at 2 km resolution over the Alpine region.…”

“…The LGM is characterised by large ice sheets in the Northern Hemisphere, a global mean temperature roughly 5 to 6.5 • C colder than today (Otto-Bliesner et al, 2006), and a global sea level of 115 to 130 m below the present-day one (Lambeck et al, 2014;Peltier and Fairbanks, 2006). Proxy records for Europe show that the climate was 10 to 14 • C colder and around 200 mm yr −1 drier during the LGM compared to recent climate conditions (Wu et al, 2007;Bartlein et al, 2011). These climatic conditions have strong implications not only for nature but also for humans.…”

“…These climatic conditions have strong implications not only for nature but also for humans. For instance, Burke et al (2017) and Wren and Burke (2019) demonstrated the importance of climate conditions and its variability as drivers of human behaviour during the LGM, e.g. the spatial distribution of populations and influence on the cultural and biological evolution (Kaplan et al, 2016).…”

Reconstructing prehistoric demography: What role for extant hunter‐gatherers?

“…Absolute estimates of demographic variables take two main forms in prehistoric contexts: (a) as descriptive values of multiple hunter‐gatherer demographic parameters (as in the group size examples discussed in Pitfall four) and; (b) as input values for calculations, equations, or computational models. Modeling approaches are used to gauge trends in population growth and decline, as well as inter‐species interactions 103 and cultural transmission 139 . While a balance needs to be struck between reality and simplicity in the creation of any model, selecting appropriate input values is of central importance in creating a useful model of population dynamics.…”

State of the Art in Paleoenvironment Mapping for Modeling Applications in Archeology—Summary, Conclusions, and Future Directions from the PaleoMaps Workshop

“…An example of this is the decrease in precipitation during HE 1 in the Southeast of the IP [80], which may have led to a local population breakdown [18]. Related to this approach-comparing models of climate history with settlement history-is the modeling of habitat suitability [82,83], which helps us to not only understand human dispersal and distribution, but also human adaptive flexibility and allows us to identify important climate parameters influencing human dispersal range.…”