Mongolian Racerunners (Eremias argus) Occupancy in Active and Inactive Siberian Marmot (Marmota sibirica) Colonies

Abstract

Habitat fragmentation caused by anthropogenic activities alters the distribution, abundance and diversity of wildlife species worldwide. As one example, Siberian marmots have experienced a >75% decline across Mongolia since the 1990s due to human harvests. Burrowing mammals are keystone; ecosystem engineers in many communities because burrowing can directly and indirectly alter the availability of resources, have effects at multiple spatial and temporal scales, and have a significant role in community organization. The deep and complex burrow systems of marmots provide underground shelters with stable microclimates that other vertebrate and invertebrate animals exploit. Our general hypothesis was that marmot colonies positively influence racerunner occupancy probability because burrows offer shelter from environmental conditions, refuges for predation, and a high diversity and number of insects and other prey items. Using occupancy modeling, we showed that the presence of a Siberian marmot colony influenced racerunner occupancy. Marmot active colony + inactive colony- ψ (AMC+IMC), p (temp+temp2) were the best approximating model. Racerunner detection was highest at approximately 24.3°C. For the aspect and elevation model, foothills had an important influence on lizard occupancy. Our results showed that marmot burrows greatly influence Mongolian racerunner occurrence and suggest that habitat modification by rodent ecosystem engineers exert ecological influence on biodiversity.