||The site is situated at the northern edge of Great Plains, at White Butte Recreation Area 20 km east of Regina, Canada. This area is a mosaic of natural mixed-grass prairie (dominated by Stipa comata, Carex eleocharis, and Beteloua gracilis) and aspen (Populus tremuloides) forest with shrubby understory (dominated by Symphoricarpos occidentalis). At this site, prairie is characterized by relatively low levels of soil resource availability
and heterogeneity (Wilson and Kleb 1996, Kleb and Wilson 1997) and intense belowground competition (Wilson 1993a). The mean July temperature is 19°C and the mean January temperature is -21°C. Mean annual precipitation is 384 mm (Environment Canada 1993).