In memory of Snowmageddon and the ecological impacts of a mild winter

by Lauren Umek

This time last year, Chicagoans were facing Snowageddon. Snow was falling and drifting at rates that the fleets of trucks couldn’t keep up with and forced a dramatic closing of Lake Shore Drive as well as many schools and businesses. This year, we’re not only lacking terrible snow related puns on the evening news but are dealing with an all around strangely mild winter. As a born and raised Chicagoan, I pride myself of winter toughness. This year’s minimal snow, that hasn’t hung around for too many days and relatively mild temperatures have made for a less than miserable winter. While those that loath winter and quite happy with this, I find myself facing a new type of seasonal anxiety. Not only does each day feel like spring is just around the corner (and therefore impending field work) but I can’t help but wonder what these mild temperatures and minimal snow mean for the ecology of the region.

For most ecologists and land managers, winters are an excellent opportunity to catch up on paperwork, data analysis, equipment maintenance and brush control. Meanwhile, the remaining months are jammed with prescribed fires, spot invasive control and vegetation monitoring.  Most of us view these “dormant” winter months as the time when most of the living creatures of the region are in a sort of suspended state, waiting for the thaw, moisture and sun of spring. However, it is important for all of us to remember how critical these winter months are, not only for our personal sanity (when else can you feel ok about spending a whole Saturday watching TV marathons?) but are also important and active time periods for nature.

Photo of my building’s alley “parking spaces” (can you find the car?) from February 2011. The lack of snow this year is definitely noticed, if not missed.


In fact, one of the most critical ecological processes, decomposition, though slower, continues throughout the winter. While most plants are dormant, the fall die back leaves a diverse buffet of organic material for the tiny critters of the soil to chomp upon. The winter months and associated snow cover are a busy time for these rodents, earthworms, microarthropods and of course bacteria and fungi. These soil dwelling critters physically and chemically digest this plant material (and often, each other) and return critical last year’s living things into next year’s nourishment soil (cue Circle of Life). The lack of freezing temperatures and snow this season are likely to have profound impacts on the rate of decomposition in our natural areas. Snow cover in particular has is important insulating properties. Snow has higher insulating properties than glass, concrete and most hardwood and is often important in maintaining warmer soil temperatures through the winter. These temperatures results in decomposition rates up to 10% greater than without snow cover (Bleak 1970). While 10% isn’t an impressively high number, it is significant for nutrient and organic matter turnover.

Decomposition is a vital ecological process that continues through the dead of winter, especially when there is snow to insulate the soil temperatures.

Beyond the implications for my favorite ecological process, snow and winter dormancy are important signals dictating phenology (anyone else have 2” daffodils that have been up for weeks) of a variety of organisms. Several insects, amphibians, reptiles and mammals burrow and take shelter underground and under snow packs, again taking advantage of snow’s insulation. While little is known about what milder winters might mean for the plants and animals in temperate regions, the potential for increased pathogens, mis-matched flowering and insect life stages and altered growth patterns are troublesome. All that being said, I think I’ll head outside and enjoy this 50 degree January day.




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9 responses to “In memory of Snowmageddon and the ecological impacts of a mild winter

  1. Rachel Friedman

    Rachel Friedman, Environmental Studies, Senior

    I selected this blog due in part because of its title, as it caught my eye. After reading the post, I couldn’t agree more with the author, as she brings up some great points as well as concerns. I am also a born and raised Chicagoan, and I believe that Chicago winters are meant to be cold. When I walk out of my house in January without a coat, I will have to admit that it makes me feel very uneasy. I know most people love the warm weather and they go out and make the most of it but all I can think to myself is that this isn’t right. We are not supposed to have 50 degrees days in January in Chicago. I feel as though people are just thinking about the present, and how great the weather is that day but they don’t look at the whole/bigger picture. People don’t realize what the effects of these warm 50-degree days have on our environment. No one thinks about what the lack of cold temperatures and snow has on the ecology of the region. With all this being said I say bring on the cold weather!

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  3. Fredell Campbell

    Fredell Campbell, Environmental Studies, Senior

    I selected this blog to comment on because I’ve always had a curiosity of the effects of global warming on pathogens (viruses, bacteria, disease). The winter time is a period of static activity for most life forms; fish slow down their metabolisms, animals hibernate and we as human beings are more often left inside our cozy homes. With the change of these seasons and how cold some areas will be, I can only wonder about the effects of disease during/after the cold season. There would have to be extensive research on the distinctive changes in disease rates in animals and human beings in between seasons of longer and shorter winters. The change of weather patterns will definitely require the regulatory process of adaption. Certain species would have to adapt their lifestyle, location, and possibly genetics in order to withstand the changes in season. An issue that may arise with the change in seasons is that pathogens may be allowed the opportunity to impact populations at an earlier period in the seasonal cycle. Not being quite knowledgeable in the dormancy periods of viruses/ bacteria vs. hibernating mammals in colder months, I find the relationship between winter and the spread of disease fascinating. The question is will the impacts be negative or positive?
    However, on the topic of organic decomposition, I don’t believe that this is a very noteworthy transaction in the winter time. Most successful decomposition of material usually takes place in warmer and moist environments more often than less. In response to :
    “The winter months and associated snow cover are a busy time for these rodents, earthworms, microarthropods and of course bacteria and fungi”
    There are more than 1,800 earth worms’ species on the planet. The species that inhabit the Midwest region commonly known as night crawlers burrow deep underground sometimes almost as deep as 6 feet for shelter during colder months. They rarely visit the surface, but will occasionally visit the surface during the warmer parts of the winter such as yesterday’s weather 50 degrees. Most other species of earth worm stay near the surface all year round and die leaving behind a legacy of egg cocoons to ensure species survivability the following spring.
    Overall, this post concerning yesterday’s wonderful weather was well needed and gave me something to think about as I enjoy other warm opportunities this winter.
    Take Care.

  4. Lauren Umek

    Thanks for the comments. I’ve grown accustomed to having 4 seasons, and think that both personally and ecologically, periods of dormancy are just as important as periods of rapid production. This winter seems to be cheating us out of our dormancy period.

    I’ve been continuing to think about these issues since posting and came across 2 new findings.

    1. At the Chicago Botanic Garden, our evaluation horticulturalist came into the offices yesterday with a fistful of Phlox flowers. FLOWERS! My daffodils are showing about 2 inches of aboveground growth, which alarms the gardener in my, but knowing that some species are seeing these warmer temperatures as cues for breaking dormancy is unnerving. Granted, the species found flowering is from a mountainous region, where flowering occurs quickly after snow melt and is not indicative of native plant behavior, it is an alarming example of how this mild temperature is influencing the flora (native and introduced) and fauna of the area.

    2. I also came across the following paper from PNAS (abstract only viewable from the link) that describes that “microbial communities are structured by environmental cues that trigger dormancy”. Again, while decomposition is slowed in winter, it still continues, and these dormancy periods have potentially profound impacts on the biotic interactions both above and belowground.

    The pathogen question is certainly an important one, and one that I know very little about. I’m both nervous and a bit excited to see how the upcoming growing season will reflect this mild winter.

    On decomposition, it is important to recall that earthworms are exotic to the Chicago region. While they are important drivers of decomposition, often dramatically accelerating decomp. rates, this process is heavily driven my other soil biota, of which are of varying levels of activity during winter months. Part of my point of mentioning decomposition in particular, other than the fact that it is my personal favorite ecosystem process, is that the finding of the importance of snow cover in maintaining the process through the winter. I had always assumed that decomposition (and most biological processes) had essentially stopped. It is interesting to remember that while things are significantly slowed, they still occur.

    Thanks for the great comments!

  5. Christine Skolnik

    I’m starting become interested in climate adaptation. We lost power for days last summer, and–more to the point– current climate tragedies in Eastern Europe.

    Makes me also think of Anthony’s “A Necessary Fear of Chaos” post and Randy’s comments:

  6. Robert Liva

    Seeing daffodils in January took me by worrisome surprise too, and a remnant population of skunk cabbage in Kane county was beginning to emerge (with one individual having developed a flower) on February 4…

    Do you have any ideas for changes in plant community dynamics that might follow this mild winter? I was wondering how plant competition might be altered in the next growing season. For example, if mature plants (native or not) are confused/stressed by with the mild winter (ie. freeze/thaw cycling; higher ambient temperatures for metabolism with low winter sunlight, etc.) might newly seeded restoration species have a competitive edge this spring? On the flip side, temperature regimes for seed stratification may not be fulfilled. Admittedly, this is an idea that came to me through rose colored glasses, I am trying to see a potential upside to the unseasonable weather.

  7. Lauren Umek

    A recent post on Rick Santorum’s thoughts on CO2 and the implications of climate change for plant communities.

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