Origins and Zoogeography of Flies (Insecta: Diptera) in Southern Yukon Grasslands

Abstract

... Because of its glacial history, the Yukon Territory is of great interest for biologists, and it is no secret that the region has a unique insect fauna (Danks and Downes, 1997). Most people who collect insects in the Yukon are attracted by the "typical" habitats of Beringia - the tundra, the mountain slopes, the extensive wetlands, rivers, and lakes. But there are many smaller, unusual, and often overlooked habitats in the Yukon with their own particular insect fauna. One of these unusual habitats is a prairie-like ecosystem characterized by xeric-adapted plants dominated by sage (Artemisia spp.: Asteraceae) and several genera of grasses on warm, south-facing slopes and river valleys. These south-facing slopes are found mostly in the southern and central Yukon, particularly along the Yukon River. ... the objectives of my study were to conduct a faunal inventory of the Diptera divesity in the southern Yukon grasslands, and to determine the zoogeographic affinities of the fly fauna of these habitats. I am testing the hypothesis that the Diptera fauna of this region is a composite, made up of widespread boreal and cordilleran species, Beringian species that survived the Wisconsinan glaciation in this refugium, and southern grassland species that have colonized the region postglacially, during the Hypsithermal. ...