The Upper Great Lakes Region contains thousands of small inland lakes. At the regional scale (upper) the four lake districts lie along gradients of precipitation, vegetation, urbanization, climate, and geology. We will use these gradients to test the generality of results from individual lake districts and conduct comparative studies. At the lake district scale (lower) lakes are influenced by different sets of driving variables, which are listed in order of importance for each lake district.
These differences will allow us to analyze responses of lakes to the frIl set of conditions occurring in the Upper Great Lakes Region. Ac the sub-district scale, study lakes were chosen to maximize understanding of responses to local driving variables: in Madison, lakes were chosen in a 2x2 design of urban vs. agricultural and high vs. low in the landscape; at NTL, lakes lie along a landscape position gradient; at ELA, lakes were selected for suitability as long-term experimental and reference systems; at Dorset, lakes were chosen along gradients of atmospheric deposition on and off the Canadian Shield.