Alpine Ecosystems are defined as biomes occurring in the cold upper altitudes atop mountains. This zone can vary with the location of the particular mountain chain. For example, in the USA, it often begins at 5,500 feet in the Cascades of Washington state, but is not seen below 11,000 feet in Rocky Mountain National Park.
Characteristics of Alpine Ecosystems
Alpine biomes can be found on mountaintops across the globe, including in the Rockies, the Himalayas, the Cascades and the Alps. However, they all share some important characteristics. Some of the defining traits of alpine ecosystems are:
- Rising temperatures as altitude increases – In an alpine environment on a mountainside, the temperatures increase up the mountain. The lower levels of the alpine biome will have plants and animals adapted to the temperatures in those zones, while the higher levels are often covered in snow and ice, including glaciers.
- Animals and plants adapted to the harsh, changing environment – These include coniferous trees and perennials and flowers that take advantage of the short warm season when the snow melts in the spring. It also includes animals such as mountain goats, which have hooves and fur adapted to living among the alpine cliffsides.
- A defined treeline – The treeline is the zone where conditions become too harsh to support growth as large as trees. When viewing a mountain from the side, this line is visible as the place where forests stop and snow, ice and rock begin. Sometimes there is a transition called the krumholtz line, where trees become stunted and warped before disappearing entirely as the altitude increases.
- Low water retention – Due to their high altitude, the tops of mountains often receive little precipitation. In places that do receive snowfall, high winds often blow away snow, leaving exposed rocky areas that contain little water.
Plants adapted to the alpine biome have unique characteristics. Here are some of the plant species found in alpine ecosystems:
- Conifers- These trees, often called "evergreens", are particularly adapted to the cool environment of lower alpine ecosystems. Some of these trees include fir, pine, spruce and cedar.
- Alpine Flowers – Different species of flowers bloom in succession in an alpine ecosystem as the snow and ice melt in the spring. Some common species include lupine, glacier lilies, alpine paintbrush, and forget-me-nots. Alpine flowers are often beautiful and colorful, an adaptation designed to increase their attractiveness to pollinating insects, which are rare at high altitudes.
- Ground Plants – Also found at the lower levels of the alpine ecosystem are low-lying groundcover plants such as ferns, lichens and mosses.
Dangers to the Alpine Biome
The alpine ecosystem contains many sturdy plants and animals adapted to the harsh environment they live in, but these ecosystems face many dangers. Climate change is a threat to the alpine biome, since it is dependent on a specific succession of temperatures and conditions up a mountainside.
Another danger is human action. People visiting alpine ecosystems can cause inadvertent damage by stepping on, picking or otherwise disturbing fragile alpine plants. Because their growing season is so short, any disruption can prevent these plants from reproducing, endangering the future survival of the species.
Further Reading About Alpine Ecosystems
Bowman, William D. and Timothy R. Seastedt, editors. Structure and Function of an Alpine Ecosystem. Oxford University Press. 2001.
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