Ecosystem Engineering Effects of Mongolian Marmots (Marmota sibirica) on Terrestrial Arthropod Communities

The Mongolian marmot (Marmota sibirica) is a large, endangered rodent species that ranges across the steppe regions of Mongolia, and parts of China and Russia. Marmot lives colonially and creates extensive burrow systems that change the soil nutrient profiles and influence plant and animal community composition and productivity. We examined the role of marmots on the diversity and abundance of ground-dwelling and flying insects. We hypothesize that the arthropod communities differ between marmot colonies and surrounding grasslands in diversity and abundance. We trapped 4765 individuals of arthropods representing 178 species of insects and 12 families of spiders. Marmot colony sites differed significantly from off colony sites by communities of ground-dwelling and flying insects. Our findings indicate that abundance and species richness of arthropods are largely associated with marmot burrows, which might be a reason for increased habitat heterogeneity, such as bare ground, specific vegetation structure, and thermoregulatory site by ecosystem engineering. Our results demonstrate that the marmots are keystone species in arid ecosystems, and have complementary, additive effects on steppe arthropod communities.