Natures wonders: ecosystem under snow (Introduction)

by David Turell @, Tuesday, May 31, 2016, 13:34 (1358 days ago) @ David Turell

Water has wonderful properties. without it there is no life. Under the proper depth of snow there is life all through the cold winter:

"Many plants and animals similarly hunker down, relying on snow cover for safety from winter's harsh conditions. The small area between the snowpack and the ground, called the subnivium (from the Latin nivis for snow, and sub for below), might be the most important ecosystem that you have never heard of.

"The subnivium is so well-insulated and stable that its temperature holds steady at around 32°F (0°C). Although that might still sound cold, a constant temperature of 32°F can often be 30 to 40 degrees warmer than the air temperature during the peak of winter. Because of this large temperature difference, a wide variety of species - birds such as the ruffed grouse and willow ptarmigan, mammals such as shrews and mice, and many species of mosses and grasses - depend on the subnivium for winter protection.

"For many organisms living in temperate and Arctic regions, the difference between being under the snow or outside it is a matter of life and death. Consequently, disruptions to the subnivium brought about by climate change will affect everything from population dynamics to nutrient cycling through the ecosystem.

"The formation and stability of the subnivium requires more than a few flurries. Winter ecologists have suggested that eight inches of snow is necessary to develop a stable layer of insulation. Depth is not the only factor, however. More accurately, the stability of the subnivium depends on the interaction between snow depth and snow density. Imagine being under a stack of blankets that are all flattened and pressed together. When compressed, the blankets essentially form one compacted layer. In contrast, when they are lightly placed on top of one another, their insulative capacity increases because the air pockets between them trap heat. Greater depths of low-density snow are therefore better at insulating the ground.


"In field experiments, researchers removed a portion of the snow cover to investigate the importance of the subnivium's insulation. They found that soil frost in the snow-free area resulted in damage to plant roots and sometimes even the death of the plant.

"In addition, plants that are active in the subnivium, such as lingonberry shrubs and alpine buttercups, are crucial for the survival of small rodents, as well as larger animals such as hare and moose, all of which graze on plants under the snow. Rodents create tunnels throughout the subnivium, which allow them to search for food without being exposed to extreme air temperatures or dangerous predators. The plant litter and faeces left by these animals stimulates plant growth, and eventually supports further plant decomposition and nutrient release. Because of the many feedback loops that are inherent in ecology, loss of one species because of disturbances to the subnivium will have ripple effects throughout communities and through entire ecosystems. " (my bold)

Comment: Two key points: Each key ecosystem illustrates the balance of life in nature. Note my bold. And, water has many wonderful qualities, without which, life would not be possible. As snow just one of many aspects of the value of water is seen. In winter water freezes at the surface, but many ponds have liquid below and life. Water is unusual that its solid form is lighter than its liquid form.

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