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Abstract

The Daurian pika (Ochotona daurica) is a burrowing, steppe-dwelling species native to the central Asian steppe and is a keystone species in many grassland ecosystems. Their presence has been shown to increase plant productivity, increase species biodiversity, and aid in the aeration and recycling of soils in the vicinity of burrow systems. Grassland ecosystems are threatened globally by the impacts of a changing climate, livestock overstocking, and agricultural production, all of which have the potential to negatively impact Daurian pika populations. This research examines Daurian pika occupancy and abundance throughout the Darhad Valley in relation to environmental factors associated with ideal Daurian pika habitat. Eighty-five plots were established across the Darhad Valley, Mongolia in which grass height, forb cover, grazing intensity, soil composition, weather, and geographical location were analyzed in relation to Daurian pika occupancy and abundance. It was found that Daurian pika occupancy and abundance was unequally distributed across the Darhad Valley, with large regional extirpations occurring across the valley according to region. Thus, we determined that region was the most important predictor of Daurian pika occupancy and abundance, informed by regional variation in soil moisture mediated by soil type, precipitation, and temperature. Furthermore, we found that Daurian pika are susceptible to flooding events, created by the combination of soil type, geographic location, land use, oscillations between sub-zero and above-freezing temperatures during the early spring, and precipitation events in adjacent montane regions which have the potential to result in the melting of snowpack and subsequent flooding throughout the low elevation valley floor. Variables previously correlated with pika survival in 2019 were found to have limited importance in determining distribution patterns amidst stochastic events. A changing climate, in combination with habitat degradation and increased grazing pressures, has the potential to contribute to long-term declines in Daurian pika populations which would have cascading detrimental effects on biodiversity levels, soil quality, and ecological resiliency of steppe ecosystems. Thus, understanding which variables might help buffer local extinctions is critical to support ecological resiliency throughout the Darhad Valley and similar Mongolian steppe ecosystems, particularly in light of a changing climate.

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