Naturalist's Corner - Winter’s Hidden Ecosystems

I recently started following another hiking and nature enthusiast, Gary Kurtz, on Facebook. He posts at Wildflowers Wisconsin. He is a  lyrical writer who opens up the world of nature to readers with keen insights and deep knowledge. His Facebook posts are perfect tidbits of information on flora, fauna, fungi and observations on what we can observe and understand  in nature. Gary also has an Etsy shop where he sells his ebooks of seasonal wildflowers. You can download them to your device and use them as you are walking in spring and summer to help with field identification. Gary graciously agreed to be our guest columnist this month and shared this Facebook post with us from November 28, 2024.  

Winter, a season of profound stillness, casts a serene yet formidable spell over the landscape. In this time of frost and scarcity, both plants and animals reveal their remarkable strategies for survival. 

Many plants retreat into dormancy. Deciduous trees—oaks, maples, and birches—surrender their leaves to conserve precious water and shield themselves from the weight of snow and ice. Their skeletal branches etch stark silhouettes against the winter sky.  In contrast, the evergreens—pines, spruces, and firs—retain their needles. These needles, cloaked in a protective wax, guard against desiccation and the biting cold. Their deep green hue allows for a small amount photosynthesis even in the heart of winter.

Beneath the snow, the forest floor holds a different kind of life. Perennial plants and bulbs lie dormant, insulated by the snow, which acts as a blanket, protecting them from the extreme cold. This layer of snow also traps heat from the ground, preventing frost from penetrating too deeply and damaging the roots.

Animals exhibit a range of behaviors and physiological changes to cope with winter. Squirrels and chipmunks busily gather and store nuts and seeds, creating caches that will sustain them when food is scarce. Birds like sandhill cranes and Canada geese skip out on long migrations to warmer climates, while monarch butterflies undertake an incredible journey to Mexico. Black bears retreat into hibernation, their metabolic rates dropping as they live off stored fat, and groundhogs enter deep hibernation, their body temperatures plummeting to conserve energy. Bats find shelter in caves, slowing their metabolism to survive on minimal energy. Coyotes, ever adaptable, remain active, hunting and scavenging with their thick fur providing insulation. White-tailed deer grow thicker coats and seek shelter in dense forests, reducing their activity to conserve energy. Remarkably, wood frogs produce a natural antifreeze, allowing them to survive being frozen.

Social behaviors also play a crucial role in winter survival. Birds like chickadees and titmice huddle together for warmth, while others roost in tree cavities. Badgers dig extensive networks of burrows, entering a state of torpor to conserve energy, while turtles and frogs burrow into mud and sand to hibernate. Even the elusive snowshoe hare changes its fur color to white, blending into the snowy landscape for camouflage. These strategies showcase the incredible adaptability of Wisconsin’s wildlife, ensuring their survival through the harsh winter.

Snow plays a crucial role in the winter ecosystem. As it accumulates, it provides insulation for plants and small animals, creating subnivean spaces (the area between the ground and the bottom of the snowpack) where creatures like mice and voles can move about safely, protected from predators and harsh weather. These small mammals remain active, foraging for seeds and roots, which helps maintain the food web.

Aquatic life also adapts to the winter conditions. Ponds and lakes may freeze over, but below the ice, water temperatures remain relatively stable. Fish, such as trout and bass, enter a state of reduced activity, slowing their metabolism to conserve energy. Some amphibians and reptiles, like frogs and turtles, burrow into the mud at the bottom of ponds, where they remain dormant until the spring thaw.

Winter is a harsh season requiring adaptation. Plants and animals employ a variety of strategies to survive the cold, and these adaptations highlight the intricate and dynamic nature of ecosystems. The stillness of winter belies the subtle and continuous interactions that sustain life, setting the stage for the renewal and growth that come with the arrival of spring.

Images - Marge Loch-Wouters