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.
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.
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.