Frozen fauna – Frossen fauna

Melting ecosystems

By Jørgen Rosvold
Snow buntings can often be observed feeding on insects that have become trapped on the ice during summer. The white background makes it easier to locate the prey. Photo: Tormod Amundsen

Perennial ice and snow cover about 10% of Earth’s land areas and contain most of our fresh water. Despite this, these frozen landscapes are among the least studied ecosystems of the world, especially when it comes to our knowledge about the role of birds and mammals in them. Glaciers and perennial snow patches are currently melting away rapidly and we know very little about which species that are dependent on these areas; even less about how they will be affected by the melting.

Birds and mammals are not normally associated with land ice and such areas are usually excluded when studying animals. However, a recent review of published observations shows that glaciers and perennial snow patches actually are important for many alpine and arctic animals around the world. A relatively large number of birds and mammals actively make use of and spend large amounts of time on glacierized landscapes.

Dense fur helps arctic and alpine animals to survive cold winters, but can be a burden during warm summer days. This musk ox enjoyes a cool respite on an alpine snow patch in central Norway. Photo: Tord Bretten, SNO

Ungulates and passerines stand out as the foremost users of land ice areas. Relief from summer heat or pestering insects seems to be main reasons that ungulates spend time on glacierized land, while for passerines these areas are mainly used for finding food.

Predators like wolverines, bears and golden eagles are also among the animals that spend time on glaciers and snow patches. In addition to finding food and shelter, birds and mammals use the ice for storing food, for getting water, as playgrounds and as easier traveling routes. One bird, the white-winged diuca finch, even build their nests on glacier ice in the Andes!

The white-winged diuca finch is the only known bird that regularely build nests directly on land ice. Photo: Douglas R. Hardy

In some areas birds and mammals can be important nutrient providers to glacial ecosystems by leaving behind masses of dung, hair, feathers and dead animals.

Many alpine mammals makes daily altitudinal migrations during warm summer days. Alpine ibex often visit glacierized areas when available, to benefit from the cool air around such sites. Photo: Wikimedia Commons

As the climate gets warmer, the need for glacierized areas will increase for some species, but at the same time these areas melt away and become less available.

Glaciers and perennial snow patches need to be managed properly as threatened ecosystems, but to do this we need to know which species that actually use them and for what purpose. If you have documented such cases, please let us know about it!

For more information:

Rosvold, J. (2015): Perennial ice and snow-covered land as important ecosystems for birds and mammals. Journal of Biogeography (in press).

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