Refuge Lake Reclassification in 620 Minnesota Cisco Lakes under Future Climate Scenarios

Abstract

Cisco (Coregonus artedi) is the most common coldwater stenothermal fish in Minnesota lakes. Water temperature (T) and dissolved oxygen (DO) in lakes are important controls of fish growth and reproduction and likely change with future climate warming. Built upon a previous study, this study uses a modified method to identify which of 620 cisco lakes in Minnesota can still support cisco populations under future climate and therefore be classified as cisco refuge lakes. The previous study used oxythermal stress parameter TDO3, the temperature at DO of 3 mg/L, simulated only from deep virtual lakes to classify 620 cisco lakes. Using four categories of virtual but representative cisco lakes in modified method, a one-dimensional water quality model MINLAKE2012 was used to simulate daily T and DO profiles in 82 virtual lakes under the past and two future climate scenarios. A multiyear average of 31-day largest TDO3 over variable benchmark (VB) periods, AvgATDO3 VB , was calculated from simulated T and DO profiles using FishHabitat2013. Contour plots of AvgATDO3 VB for four categories of virtual lakes were then developed to reclassify 620 cisco lakes into Tier 1 (AvgATDO3 VB < 11 • C) or Tier 2 refuge lakes, and Tier 3 non-refuge lakes (AvgATDO3 VB > 17 • C). About 20% of 620 cisco lakes are projected to be refuge lakes under future climate scenarios, which is a more accurate projection (improving the prediction accuracy by~6.5% from the previous study) since AvgATDO3 VB was found to vary by lake categories.

Massive peatland carbon banks vulnerable to rising temperatures

“…Based on current greenhouse gas emission rates 16 , forcing estimates in line or greater than the RCP 8.5 scenario are likely to occur. This will result in 2.6-4.8°C increases in global mean surface temperatures by 2100 17 , with Minnesota experiencing 4.07-4.14°C increases in annual air temperature 18 . However, both models and observations indicate that northern boreal forests and tundra will continue to be exposed to greater warming than most other terrestrial biomes.…”

Cisco population characteristics in Wisconsin lakes in relation to lake‐ and landscape‐level factors

“…Determining appropriate management strategies requires an understanding of how environmental conditions influence population status. Broadly, our results suggest that Cisco relative abundance and growth in inland Wisconsin lakes were influenced by a variety of physical, climatic, catchment, and limnological characteristics, several of which have also been identified as important predictors of Cisco occurrence or persistence (Jacobson et al 2013;Honsey et al 2016;Jiang et al 2017). The EpiHypo, which served as a general measure of coldwater habitat availability, was the most important predictor of Cisco CPUE among lakes.…”

“…Observed and projected declines in Cisco populations have prompted examination of patterns in Cisco presence-absence and extirpation risk in relation to lake-and landscape-level environmental factors to identify refuge lakes and conditions that promote Cisco persistence (e.g., Jacobson et al 2013;Honsey et al 2016;Jiang et al 2017). These studies provide valuable information in terms of identifying where Cisco populations may persist in the future given projected climate shifts and other threats to Cisco populations, which generally include factors related to nutrient loading, land use change, and associated changes in oxythermal habitat (Jacobson et al 2012;Honsey et al 2016;Lyons et al 2018).…”

“…2016; Jiang et al. 2017). These studies provide valuable information in terms of identifying where Cisco populations may persist in the future given projected climate shifts and other threats to Cisco populations, which generally include factors related to nutrient loading, land use change, and associated changes in oxythermal habitat (Jacobson et al.…”

Oxythermal habitat as a primary driver of ecological niche and genetic diversity in cisco (Coregonus artedi)

“…T DO3 values at the deepest depth should have the lowest T DO3 value and thus represent the most optimal lakewide habitat for cisco. T DO3 for our remaining sites was estimated from data collected by the Minnesota Department of Natural Resources or Pollution Control Agency (n=8) or taken from the literature using the same methods that we used (n = 3; Fang et al 2010;Jiang et al 2017).…”