Climate Change in the BWCAW


As midwesterners, we may feel as though we are insulated from threat of climate change. Living smack in the middle of the continent, rising sea levels do not seem to be an immediate concern for us. Those of us that struggle with cold weather might even grow excited at the prospect of shorter, more mild winters, and few farmers will complain about the lengthened growing seasons that climatologists forecast in the coming decades. However, we cannot forget that each benefit we might see as the midwest warms will bring its own set of tradeoffs. The most alarming of these tradeoffs involves one of Minnesota’s most iconic landscapes: the Boundary Waters Canoe Area Wilderness (BWCAW). For generations, the BWCAW has been a popular destination for adventurers, nature lovers and family vacationers from across the country and a vital part of northern Minnesota’s economy. It occupies a special place in the hearts of many and remains an integral part of our state’s identity and culture. As such, it is of utmost importance that we begin to think critically about the changes that the Boundary Waters will see in the coming years as a result of climate change. What will the Boundary Waters look like by century’s end? Will predicted ecological changes also have economic and socio-cultural impacts? What role will we, as allies and lovers of the Boundary Waters, play in this change?

Biomes of North America

Figure 1: Biomes of North America (boreal forest in dark green)

The boreal forest forms the largest terrestrial ecosystem on the planet. Characterized by coniferous trees such as pine, spruce and larch, it comprises a whopping 33% of global forest cover. (1) On our continent, the boreal forest stretches in a broad band from Alaska to the eastern coasts of Canada, occasionally dipping south across the continental US border. We in Minnesota are fortunate enough to be living in close proximity to one of those southern dips. Drive north from the Twin Cities, and at a certain point you might notice a rather swift change in the landscape. This is consistently one of my favorite parts of any trip to the Boundary Waters–where the oaks and maples of the central part of our state suddenly give way to the conifers that dominate the wild north. Unfortunately, this Northwoods’ aesthetic we have come to associate with Minnesota wilderness will be under great threat over the next several decades. Accredited biologist and director of the U of M Center of Forest Ecology Lee Frelich predicts that warming temperatures in Minnesota due to human-induced climate change will push the boreal forest out of our state before the end of the century. (2)

 

Boreal Forest

Boreal forest on the North Shore of Lake Superior in Minnesota

As some may already know, Minnesota houses three different biomes–regions dominated by a specific type of ecosystem. Southwestern Minnesota is home to the prairie grassland biome, which transitions to temperate deciduous forest in the central part of the state and then northern coniferous forest in the northeast. According to Frelich, the transition points between these biomes are determined by a delicate balance between precipitation and evaporation. In simple terms, areas that see less precipitation than evaporation on an annual basis will be grassland. Areas with more precipitation than evaporation will be forested (see the maps below). (2, 3)  As the climate warms and evaporation rates across the state increase, the prairie-forest border, which currently runs diagonally through the central part of our state from the northwest to the southeast,

MN Biomes and PPET

Figure 2: Minnesota’s biomes and potential evapotranspiration (or P-PET, the amount of evaporation vs. precipitation).3 On the left, grasslands are in beige, deciduous forest is in light green, and coniferous forest is in dark green. As you can see, the location of the prairie-forest border appears to be quite dependent on P-PET.

 

could move up to 300 miles to the north by the year 2100. (2) This would put the Boundary Waters right in the vicinity of the prairie-forest border, making for a very different landscape than the one we see there today. The pine, spruce, and birch currently abundant throughout the region would be driven northward into Canada by increasingly frequent droughts, straight line winds, and warm-weather invasive species like earthworms, buckthorn and garlic mustard. (2) In their place, we would most likely see the same type of maple and oak savanna found today in west central Minnesota. Frelich identifies the Gneiss Outcrops Science and Natural Area near Granite Falls as a potential gauge for what the Boundary Waters might look like in the future. It lies very near the current prairie-forest boundary, and like the Boundary waters, it has relatively thin soil and is underlain by outcrops of igneous rock. (2)

Climate change will also affect the Boundary Waters’ fauna. Wolves and deer will likely do just fine, but other iconic species that have evolved to survive in the boreal forest could disappear. Most notable among these are moose, lynx, and certain species of owl. (2, 4) Overall, it is a rather somber outlook for those of us that have grown up as patrons of Minnesota’s Northwoods. They have long been a part of our heritage–a defining characteristic of our state and an enormous source of pride for our people. They are also a critical source of revenue for northern Minnesota communities where recreation and tourism are main drivers of the local economy. Many fear that a change in the landscape could cause tourism to dwindle in the region, negatively affecting towns along the North Shore and inland near the Boundary Waters. (5)

With many scientists predicting that some degree of climate change is inevitable, we must now begin to consider how we might deal with landscape change in the Boundary Waters. Leslie Brandt of the U.S. Forest Service identifies a number of strategies for doing so. The first, termed resistance, would involve efforts to mitigate or completely prevent environmental disturbances related to climate change. This might include activities such as ramping up efforts to get rid of invasive species, pests, and diseases or creating fuelbreaks–gaps in the forest that may prevent the spread of fires. (6) The second strategy that Brandt discusses is resilience. Resilience is more of a roll-with-the-punches type of approach; instead of attempting to eliminate climate-related environmental disturbances outright, it would seek to ensure that the wilderness can weather those disturbances without changing drastically. Employing this strategy might involve activities like clearing and revegetating areas after fires, wind storms, or pest outbreaks. (6) The third and fourth strategies, response and realignment, accept the inevitability of landscape change and take steps to facilitate the transition to a new landscape. Adopting these approaches, we might begin planting species that are predicted to do well in a warmer climate or create wildlife migration corridors. (6, 7)

Whatever happens to the Boundary Waters in the coming decades, we must remember that it will still be beautiful and it will still hold value as long as it continues to be a wilderness. Frelich points out that the Boundary Waters of the future could take on the same aesthetic as southern Minnesota before the arrival of Europeans, perhaps giving us a glimpse of the ancient prairie landscapes of the midwest that predated modern civilization. However, while this may be an exciting prospect for some, for others it would be immensely difficult to simply let the Northwoods leave. We grew up with the pines, the birch, the moose. Would it feel the same without them? Would the Boundary Waters still possess the same magic without the Northwoods? Well, the good news is that we do not necessarily have to be resigned to the idea that the Boundary Waters will soon cease to be the place it is now.  We must remember that the predictions outlined above assume a “business as usual” scenario. While some landscape change is likely unavoidable, it can be minimized if we make sincere efforts to curb greenhouse gas emissions in the near future. Though it will require swift, collective action and cooperation between a wide variety of parties, it is certainly possible. We at the Friends of the Boundary Waters Wilderness hope to help spur this much needed action and facilitate cooperation on climate change because of its relevance to our mission of protecting and preserving the Boundary Waters. Over the coming months, we will be providing updates and commentary on climate change-related news in an attempt to spread an awareness of the nature of the issue and how it could affect the landscapes we love. Please join us in this campaign and stay tuned for further news and information!

 

References

1 The Taiga or Boreal Forest. (2013, October 14). Retrieved from http://w3.marietta.edu/~biol/biomes/boreal.htm

2 Frelich, L. E. [White Raven Productions]. (2015, July 27). Dr. Lee Frelich -Effects of Climate Change & Invasive Species on BWCA. [Video File]. Retrieved from https://www.youtube.com/watch?v=-b1sRzwA0ZE

3 Danz, N. P., Frelich, L. E., Reich, P. B., & Niemi, G. J. (2013). Do vegetation boundaries display smooth or abrupt spatial transitions along environmental gradients? Evidence from the prairie–forest biome boundary of historic Minnesota, USA. Journal of Vegetation Science, 24: 1129-1140. Retrieved from https://www.uwsuper.edu/acaddept/naturalsciences/employees/ndanz/upload/danz_etal_2013_w_appendices.pdf

4 Marcotty, J. (2013, October 17). Saving the great north woods. Star Tribune. Retrieved from http://www.startribune.com/star-tribune-special-report-saving-the-great-north-woods/228250501/

5 Bitsura-Mazaros, K., Smith, J. W., Seekamp, E., Davenport, M. A., Nieber, J., Wilson, B., Anderson, D. H., Messer, C., & Kanazawa, M. (2015). Building Coastal Climate Readiness along the North Shore of Lake Superior. Michigan Journal of Sustainability, 3. Retrieved from http://quod.lib.umich.edu/m/mjs/12333712.0003.009?view=text;rgn=main

6 Brandt, L. (2013). Climate Change and the Boundary Waters. Retrieved from https://forestadaptation.org/sites/default/files/BOUNDARYWATERSCC.pdf

7 Stephenson, N. L. & Millar, C. I. (2012). Climate change: Wilderness’s greatest Challenge. ParkScience, 21(3). Retrieved from https://www.fs.fed.us/psw/publications/millar/psw_2012_millar002.pdf

| More

###