We humans don’t always like the winter snow for its inconvenience and sometimes safety threat. For many animals, the snow-cover makes winter the best time of year. Scientists who study life in this seasonal microenvironment under the snow call it the subnivium ecosystem. It allows many species of plants and animals to exist that could not survive without snow.
The first scientific writings about the subnivium world were circulated by a lepidopterist (a scientist who studies butterflies) named Vladimir Nabokov. Nabokov was investigating butterflies whose caterpillars eat plants known as blue lupines. These butterflies lay their eggs on the stems of the lupines a few inches above the ground. When snow covers the area, the eggs are protected from the very low temperatures of the mountains where the butterflies live. Scientists conducted a study of those same butterflies in 2019 when there was a significant decrease in the snow cover. They found a 43% decrease in the number of butterflies produced.
This is just one example of life in the subnivium ecosystem. Ruffed grouse burrow into the snow at night and stay in an igloo-like area that can be 50 degrees warmer than the outside air. In wintertime, a surprising number of animals live in the warmer subnivium ecosystem. Wolverines, martens, voles, mice, shrews, red squirrels, and even bears take advantage of heavy snow cover. The protection of snow allows abundant life at high elevations and in polar areas.
Every part of Earth is home to living things because of the design of the animals and plants and the design of water that gives snow thermodynamic properties. It is easy to overlook the statement God made to Job about “the treasures of the snow” (Job 38:22). The simplicity of those words describes a whole world of life in the subnivium ecosystem and the treasure of water stored on snow-covered mountains. The treasure house of snow speaks of the intelligence built into every corner of creation.
— John N. Clayton © 2021
Data from National Wildlife magazine, February-March 2021.