Mitogenomic Relationships and Demographic History of the Daurian Ground Squirrel ( <i>Spermophilus dauricus</i> ) in Response to Human Activity

Species are the constituent units of ecosystems, and even species that have severe conflicts with humans play irreplaceable and important roles in maintaining ecosystem stability. <i>Spermophilus dauricus</i> has long been considered a harmful animal because of its ability to damage grasslands and agriculture, as well as its status as a primary host of <i>Yersinia pestis</i>. Consequently, it has been subject to eradication areas in human activity areas, which may lead to a reduction in its genetic diversity. Genetic diversity is the core foundation for maintaining species continuity, yet this is precisely the aspect lacking in research on <i>S. dauricus</i>. In this study, we performed mitochondrial genome sequencing of 73 individuals sampled across an extensive geographic region of <i>S. dauricus</i> and conducted population genetic and species distribution model analyses. The results revealed that <i>S. dauricus</i> is primarily distributed in three fragmented yet connected regions: the Northeast China Plain distribution area, the Hulunbuir Plateau distribution area, and the Bashang Plateau distribution area. Populations across these three present regions exhibit genetic differences but do not display subspecific relationships. The populations in the Hulunbuir Plateau and Bashang Plateau likely originated from the population in the Northeast Plain. Furthermore, all three populations of <i>S. dauricus</i> have experienced a continuous population decline in the past few thousand years, which we hypothesize may be related to the development of human rice cultivation and nomadism over the past few thousand years. This study highlights the role of human production activities in the decline of the effective population of rodents.