Resilience in Natural Ecosystems

Minnesota is a hotspot of past and future warming in the lower 48 states.¹ Future Minnesota winters will be milder and see more precipitation, with fewer cold and very cold days, less snowfall and snowpack, and more winter rain.² Future springs are projected to become wetter and warmer. Growing seasons will on average get longer. Future warm seasons will be hotter and have more variable precipitation. Some future summer and early autumn months will be warmer, wet and humid while others will be hotter, dry and drought prone. The transition from plentiful moisture to drought conditions will occur more quickly than it did in the past. Short (<1 hour) to long (multi-day) heavy rain events are projected to become more frequent and more intense. Severe convective weather is projected to become more frequent and more severe.³

These changes will have profound impacts on Minnesota’s ecosystems.

Climate change will make parts of Minnesota less suitable for some tree species and more suitable for others. In northern Minnesota a decrease in extreme cold will allow more southern tree species to overwinter and outcompete slower-growing species. An increase in drought may favor more drought-tolerant species across the state. Southern boreal forest species like paper birch, black spruce, quaking aspen, and balsam fir are projected to decrease, while fast-growing maples and drought-resistant oaks will continue to become more common across northern Minnesota.⁴ Warming may help the spread of invasive species like buckthorn and round leaf bittersweet, particularly in northern Minnesota.^4–6

Minnesota famously sits at the prairie-forest border and contains three major North American biomes. If the world follows a higher emissions pathway the prairie-forest border may shift northeast, decreasing the area of Minnesota suitable for forests and increasing the area suitable for prairie.⁷

Minnesota has seen a rapid increase in forest disturbance in recent decades, partly driven by enormous increases in damage from tree pests.^8,9 Tree pests benefit from a warming climate in multiple ways. Warming means easier overwintering (larch casebearer, eastern larch beetle, emerald ash borer),  the opportunity for an extra generation each year (eastern larch beetle), improved synchrony with host trees (spruce budworm, larch casebearer), and access to more stressed trees with weakened defenses (all species).^10–14 Climate change is projected to continue the trend of increased forest disturbance and tree stress, with damage from pests, pathogens, drought, deer browse, wildfire, heatwaves, flooding, phenological mismatches, lightning, hail and windstorms all possibly becoming more frequent and more severe in the future.¹⁵ Particularly concerning is the projected increase in compound stressors, like hot droughts or pest outbreaks during droughts, where trees’ ability to respond to any one threat is diminished and damage is amplified.¹⁶

Urban trees are a critical component of cities, providing shade, habitat, air quality benefits and erosion control. Forest disturbance is also harmful for city trees and forests, with drought, pests like emerald ash borer and pathogens like Dutch elm disease and oak wilt reducing tree cover even as dangerous heat continues to rise.¹²

Climate change impacts species in many complex ways, sometimes even beneficially. Below are some expected impacts for several charismatic Minnesota animals. While this discussion is not comprehensive, it shows some of the complex responses animals may have to a changing climate.

A warming climate harms Minnesota moose in multiple ways, including a loss of southern boreal forest habitat, an increase in heat stress and increased exposure to diseases and parasites.¹⁷  Loons are sensitive to anomalous warmth and heavy rains during nesting season, and the extent of their breeding range is expected to shift north and shrink in Minnesota.^18,19 United States butterfly populations have already been negatively impacted by warming.²⁰ The endangered Karner blue butterfly is particularly sensitive to climatic shifts. Warming decreases the size and fecundity of Karner blue females and can lead to too-early emergence relative to their host plant wild lupine.^21,22

The loss of harsh winters is expected to be beneficial for Minnesota mammals at the northern end of their historical range. The populations of species like white-tailed deer, opossums, and the southern flying squirrel are all expected to benefit from warming.^23,24 

Statewide summertime lake surface temperatures have warmed over 4℉ since the 1960s.²⁵ This warming will continue, with even lake bottoms projected to get significantly warmer in the future.² Lakes are projected to become less habitable for coldwater species like walleye and cisco, but better for warm water species like largemouth bass.26 Warmer lakes are projected to increase the number of days with harmful algal blooms.²⁷ The amount of time lakes spend stratified in summer is projected to increase, leading to deoxygenation and harmful changes in nutrient cycling.²⁸

Minnesota lakes have lost an average of 1.5-3 weeks of ice cover over the last century.^25,29 Studies suggest that even lakes as far north as Brainerd or Detroit Lakes could occasionally experience winters without complete ice cover by the end of this century.³⁰ The loss of ice has many impacts on lakes, like increases in shore erosion and decreases in wild rice harvests.³¹

1. Crimmins, A. R. Fifth National Climate Assessment. Fifth National Climate Assessment https://nca2023.globalchange.gov/ (2023). 

2. Liess, S. et al. MN CliMAT. Fine-scale Climate Projections over Minnesota for the 21st Century. https://app.climate.umn.edu/?output_type=numDif&scenario=ssp370_2060-2079&model=ensemble&variable=tmax-degF&time_frame=yearly&aoi=p%7EMN_outline%7E0#intro_pane (2025). 

3. Future Global Convective Environments in CMIP6 Models - Lepore - 2021 - Earth’s Future - Wiley Online Library. https://agupubs.onlinelibrary.wiley.com/doi/10.1029/2021EF002277. 

4. Handler, S., Janowiak, M. & Swanston, C. Climate Change Field Guide for Northern Minnesota Forests: Site-Level Considerations and Adaptation. https://handle.nal.usda.gov/10113/6949547 (2017) doi:10.32747/2017.6949547.ch. 

5. Responses of insect pests, pathogens, and invasive plant species to climate change in the forests of northeastern North America: What can we predict? This article is one of a selection of papers from NE Forests 2100: A Synthesis of Climate Change Impacts on Forests of the Northeastern US and Eastern Canada. https://cdnsciencepub.com/doi/10.1139/X08-171. 

6. Reich, P. B. et al. Geographic range predicts photosynthetic and growth response to warming in co-occurring tree species. Nat. Clim. Change 5, 148–152 (2015). 

7. Climate-Biome Envelope Shifts Create Enormous Challenges and Novel Opportunities for Conservation. https://www.mdpi.com/1999-4907/11/9/1015. 

8. Wilson, D. C., Morin, R. S., Frelich, L. E. & Ek, A. R. Monitoring disturbance intervals in forests: a case study of increasing forest disturbance in Minnesota. Ann. For. Sci. 76, 78 (2019). 

9. 2024 Forest Health Annual Report. https://files.dnr.state.mn.us/assistance/backyard/treecare/forest_health/annualreports/2024-annual-report.pdf (2024). 

10. Cold tolerance of the invasive larch casebearer and implications for invasion success - Ward - 2019 - Agricultural and Forest Entomology - Wiley Online Library. https://resjournals.onlinelibrary.wiley.com/doi/10.1111/afe.12311. 

11. The effects of chilling and forcing temperatures on spring synchrony between larch casebearer and tamarack - Nanninga - 2023 - Agricultural and Forest Entomology - Wiley Online Library. https://resjournals.onlinelibrary.wiley.com/doi/10.1111/afe.12588. 

12. Kraker, D. In northern Minnesota, researchers and foresters prepare for emerald ash borer invasion. MPR News https://www.mprnews.org/story/2024/03/13/in-northern-minnesota-researchers-and-foresters-prepare-for-emerald-ash-borer-invasion (2024). 

13. Eastern larch beetle, a changing climate, and impacts to northern tamarack forests. in Bark Beetle Management, Ecology, and Climate Change 261–300 (Academic Press, 2022). doi:10.1016/B978-0-12-822145-7.00001-5. 

14. Bellemin-Noel, B., Bourassa, S., Despland, E., De Grandpre, L. & Pureswaran, D. Improved performance of the eastern spruce budworm on black spruce as warming temperatures disrupt phenological defences. Glob. Change Biol. https://onlinelibrary.wiley.com/doi/10.1111/gcb.15643. 

15. Seidl, R. et al. Forest disturbances under climate change. Nat. Clim. Change 7, 395–402 (2017). 

16. Breshears, D. D. et al. Underappreciated plant vulnerabilities to heat waves. New Phytol. 231, 32–39 (2021). 

17. Climate change effects on deer and moose in the Midwest - Weiskopf - 2019 - The Journal of Wildlife Management - Wiley Online Library. https://wildlife.onlinelibrary.wiley.com/doi/10.1002/jwmg.21649. 

18. Aanji-Bimaadiziimagak o’ow Aki Climate Change Vulnerability Assessment. (2023). 

19. Conservation Status of North American Birds in the Face of Future Climate Change | PLOS One. https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0135350. 

20. Rapid butterfly declines across the United States during the 21st century | Science. https://www.science.org/doi/10.1126/science.adp4671. 

21. Bristow, L. V. et al. Warming experiments test the temperature sensitivity of an endangered butterfly across life history stages. J. Insect Conserv. 28, 1–13 (2024). 

22. 22. Patterson, T., Grundel, R., Dzurisin, J. D. K., Knutson, R. & Hellman, J. Evidence of an extreme weather-induced phenological mismatch and a local extirpation of the endangered Karner blue butterfly. Conserv. Sci. Pract. 2, (2020). 

23. Modelling the spatial distribution of selected North American woodland mammals under future climate scenarios - Deb - 2020 - Mammal Review - Wiley Online Library. https://onlinelibrary.wiley.com/doi/10.1111/mam.12210. 

24. Southern flying squirrels are climate migrants | Natural Resources Research Institute. https://nrri.umn.edu/news/flying-squirrels. 

25. Climate Trends: What is happening? Minnesota Department of Natural Resources https://www.dnr.state.mn.us/waters/watermgmt_section/shoreland/climate-trends/what-happening.html. 

26. Hansen, G. J. A., Read, J. S., Hansen, J. F. & Winslow, L. A. Projected shifts in fish species dominance in Wisconsin lakes under climate change. Glob. Change Biol. 23, 1463–1476 (2017). 

27. Chapra, S. C. et al. Climate Change Impacts on Harmful Algal Blooms in U.S. Freshwaters: A Screening-Level Assessment. Environ. Sci. Technol. 51, 8933–8943 (2017). 

28. Phenological shifts in lake stratification under climate change | Nature Communications. https://www.nature.com/articles/s41467-021-22657-4. 

29. Variable phenology but consistent loss of ice cover on 1213 Minnesota lakes - Walsh - 2025 - Limnology and Oceanography Letters - Wiley Online Library. https://aslopubs.onlinelibrary.wiley.com/doi/10.1002/lol2.70015. 

30. Sharma, S. et al. Widespread loss of lake ice around the Northern Hemisphere in a warming world. Nat. Clim. Change 9, 227–231 (2019). 

31. Climate change contributes to the decline in off-reservation tribal harvest availability in the Great Lakes region | Communications Earth & Environment. https://www.nature.com/articles/s43247-025-02233-0.