Late Pleistocene Expansion of Small Murid Rodents across the Palearctic in Relation to the Past Environmental Changes.

Katarzyna Kozyra,Heliodor Wierzbicki,Magdalena Moska,Tomasz M Zając,Michal Stanko,Hermann Ansorge,Pavel Stopka

doi:10.3390/genes12050642

Abstract

We investigated the evolutionary history of the striped field mouse to identify factors that initiated its past demographic changes and to shed light on the causes of its current genetic structure and trans-Eurasian distribution. We sequenced mitochondrial cyt b from 184 individuals, obtained from 35 sites in central Europe and eastern Mongolia. We compared genetic analyses with previously published historical distribution models and data on environmental and climatic changes. The past demographic changes displayed similar population trends in the case of recently expanded clades C1 and C3, with the glacial (MIS 3–4) expansion and postglacial bottleneck preceding the recent expansion initiated in the late Holocene and were related to environmental changes during the upper Pleistocene and Holocene. The past demographic trends of the eastern Asian clade C3 were correlated with changes in sea level and the formation of new land bridges formed by the exposed sea shelf during the glaciations. These data were supported by reconstructed historical distribution models. The results of our genetic analyses, supported by the reconstruction of the historical spatial distributions of the distinct clades, confirm that over time the local populations mixed as a consequence of environmental and climatic changes resulting from cyclical glaciation and the interglacial period during the Pleistocene.

Highlights

Over the Pleistocene and Holocene, the global environment has undergone cyclical large-scale shifts that have affected ecosystems, species’ spatial structures and population trends [1,2,3,4]
The distributions of the specimens classified into clades C4 and C5 overlap and cover mostly central and eastern China, with the northernmost locations being near Primorski Krai in the Russian far east and the southernmost ones below 30◦ N
Results of recent and glacial environmental niche modelling (ENM) indicate the presence of habitats potentially suitable for striped field mouse (SFM) in south Japan (Figure 7, Figures S3 and S4 in Supplementary Materials S4)

Summary

Introduction

Over the Pleistocene and Holocene, the global environment has undergone cyclical large-scale shifts that have affected ecosystems, species’ spatial structures and population trends [1,2,3,4]. Deforestation, agricultural development, especially the cultivation of agricultural crops and the creation of a secondary (cultural) steppe, have positively affected the spread of several rodent species (European ground squirrel Spermophilus citellus, European hamster Cricetus cricetus, common vole Microtus arvalis, several mice species) from the Asian steppes to central Europe [5,6,7] These pressures are unlikely to diminish in the future, so we need to acquire knowledge of the evolutionary ability of species to adapt to changing environments and their response to changes in the availability and extent of species preferred habitats, related to glacial and non-glacial cycles and more recently to human activity [8,9]. Learning about the factors affecting the historical colonization of various species may provide insight into the processes behind current expansions, especially in the context of non-native and invasive species, to specify future trends, and to forecast the directions and scales of a species’ continued dispersion

Methods

Results

Discussion

Conclusion