Potential effects of climate change on inland glacial lakes and implications for lake-dependent biota in Wisconsin: final report April 2013

The economic vitality and quality of life of many northern Wisconsin communities is closely
associated with the ecological condition of the abundant water resources in the region. Climate change
models predict warmer temperatures, changes to precipitation patterns, and increased evapotranspiration in
the Great Lakes region. Recently (1950-2006), many regions of Wisconsin have experienced warming, and
precipitation has generally increased except in far northern Wisconsin. Modeling conducted by the
University of Wisconsin Nelson Environmental Institute Center for Climate Research predicts an increase
in annual temperature by the middle of the 21st
century of approximately 6°
F statewide, and an increase in
precipitation of 1”–2”. However, summer precipitation in the northern part of the state is expected to be
less and winter precipitation will be greater. By the end of the 21st century, the magnitude of changes in
temperature and precipitation are expected to intensify.
Such climatic changes have altered, and would further alter hydrological, chemical, and physical
properties of inland lakes. Lake-dependent wildlife sensitive to changes in water quality, are particularly
susceptible to lake quality-associated habitat changes and are likely to suffer restrictions to current breeding
distributions under some climate change scenarios. We have selected the common loon (Gavia immer) to
serve as a sentinel lake-dependent piscivorous species to be used in the development of a template for
linking primary lake-dependent biota endpoints (e.g., decline in productivity and/or breeding range
contraction) to important lake quality indicators. In the current project, we evaluate how changes in
freshwater habitat quality (specifically lake clarity) may impact common loon lake occupancy in Wisconsin
under detailed climate-change scenarios. In addition, we employ simple land-use/land cover and habitat
scenarios to illustrate the potential interaction of climate and land-use/land cover effects. The methods
employed here provide a template for studies where integration of physical and biotic models is used to
project future conditions under various climate and land use change scenarios. Findings presented here
project the future conditions of lakes and loons within an important watershed in northern Wisconsin – of
importance to water resource managers and state citizens alike.