The experimental lakes

Our studies were conducted in Paul, Peter, and Tuesday Lakes (Fig. 2.1). These lakes lie on the grounds of the University of Notre Dame Environmental Research Center (UNDERC) near Land o' Lakes, Wisconsin, U.S.A. (89°32′ W, 46°13′N). UNDERC occupies more than 2800 ha of land donated to the University of Notre Dame in the 1940s ‘for the scientific purposes of Forestry, Botany, Biology and allied sciences’ (Gillen, 1939). The limnological potential of the property had been recognized in the 1920s, when E. A. Birge, C. Juday and associates sampled most of its lakes (Beckel, 1987).

Because the UNDERC facility is privately owned and protected, it offers remarkable opportunities for field experimentation. Fish populations in the experimental lakes are unexploited, and can be manipulated without the complications of sport or commercial fishing. The drainage basins are undeveloped and lie entirely within the UNDERC property, so disturbances or chemical inputs to the lakes that might confound ecosystem experiments are minimized. UNDERC is about 40 km from the University of Wisconsin's Trout Lake Station, a national center of limnological activity for more than 50 years (Magnuson & Bowser, 1990). The array of intensively studied lakes in the region provides additional reference (or ‘control’) systems for manipulative experiments (Carpenter et al., 1989) as well as opportunities for comparative studies (Carpenters et al., 1991).