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.

Genesis of Flea-Born Transmission of Plague Microbe, Yersinia pestis: Two Approachs – Molecular-Genetic and Ecological Ones

Two approaches to studying the origin and transmission mechanism of the flea-borne plague pathogen, Yersinia pestis: molecular-genetic and ecological ones – are considered in this review. The molecular genetic approach is based on saltation evolutionary ideology and relies upon the phenomenon of horizontal gene transfer of pla and ymt as critical evolutionary events. Further deletion of some structural and regulatory genes optimized “blockage” mechanism of transmission. The Ecological approach is based on the modern synthetic theory of evolution. It posits a gradual population-genetic transformation in the Marmot – Flea (Marmota sibirica – Oropsylla silantiewi) transitional (heterothermal, heteroimmune) host-parasite system in Late Pleistocene – Holocene epochs. The best prospects for disclosing the mechanisms of evolutionary formation of flea-borne Y. pestis transmission consist in the synthesis of molecular-genetic and ecological approaches.