Pollinators are attracted to mounds created by burrowing animals (marmots) in a Mongolian grassland

Burrowing by semi-fossorial rodents modifies soil properties and plant communities. The effects of this burrowing on plants, however, are typically evaluated only by assessing changes in photosynthetic or production traits, not pollination traits. Therefore little is known about the indirect effects of burrowing on pollinators through its effects on the emergence of insect-pollinated plants. We recorded the relative elevation, grass cover, and flower height of insect-pollinated plant species; the number of inflorescences; and the number of pollinators in a marmot colony on the Mongolian steppe. We compared these parameters on and off marmot mounds and searched for factors that might explain variations in pollinator biodiversity at the plot and individual-plant levels. Flower numbers and flower visitation frequency per plot were significantly higher in the on-mound plots. The number of pollinators at the plot level was positively correlated with the relative elevation and number of flowers. Species richness of the pollinators was negatively correlated with grass cover. These results demonstrate that mounds created by marmots attracted pollinators by increasing flower numbers and by making flowers more conspicuous by raising them above the surrounding vegetation or removing that vegetation.