Protecting cisco (Corego- nus artedi Leseur) oxythermal habitat from climate change: building resilience in deep lakes using a landscape approach
Jacobson, Peter C.; Fang, Xing; Stefan, Heinz G.; Pereira, Donald L.
Cisco (Coregonus artedi Lesueur) was projected to persist in at least 171 deep, clear lakes in a climate-warmed Minnesota, U. S. A. A process-oriented, dynamic, one-dimensional yearround lake water quality model was used to predict coldwater habitat as a function of Secchi depth (a surrogate of lake productivity) and geometry ratio = As 0.25 /Hmax (a measure of relative depth and strength of stratification) for a series of lake types in Minnesota. Late-summer hypolimnetic oxygen concentrations were predicted to remain sufficiently high to provide coldwater habitat within the refuge lakes even with longer durations of stratification after climate warming. Catchments of refuge lakes were prioritised based on two components: 1) threat (changes in land use) and 2) investment efficiency (total surface area of refuge lakes protected per amount invested). Priority scores were calculated for each refuge lake catchment based on the two components. Conservation strategies can be targeted in critical areas of the prioritized catchments to prevent future degradation of water quality in refuge lakes from changes in land use.