Unique adaptations of plants and wildlife to the cold
Figure 4. Vegetation distribution of the Arctic and Sub-Arctic. The most recent detailed map is available at www.geobotany.uaf.edu/cavm and www.caff.is. The Circumpolar Arctic Vegetation Map (CAVM) project is an international effort to map the vegetation and associated characteristics of the circumpolar region, using a common base map. The base map is a false colour infrared image created from Advanced Very High Resolution Radiometer (AVHRR) satellite data.
Arctic vegetation is less diverse compared to that of more southerly latitudes, but it nonetheless includes a wide range of plant life with unique adaptations to a harsh environment. There are taiga forests of pine, spruce, willow, birch and poplar, flat tundra, steppe landscapes, wetlands, polar deserts, and cliffs fringed at their bases by rich vegetation fertilized over decades by the droppings of nesting seabirds. Ground lichens play an important role in many regions as the primary food source for reindeer and caribou during winter. Some vegetation types are found only in the Arctic and are under acute threat from rising temperatures.
The Arctic is characterized by extremes of sunlight, darkness and colours
Figure 5. Annual cycle of sunlight in the Arctic.
The Arctic is often described as a place of utter darkness or white snow in winter and of midnight sun during the summertime. In fact, there are few places on Earth where the sun displays so much variation in colour due to the low angle of the sun reflected on the mountains, snow and sky over long periods of time. North of the Arctic Circle the sun disappears during winter for days to months, depending upon latitude, leaving the sky in a palette of blues, greys, reds, oranges and purples. The moon, snow, angle of the sun and the northern lights add to this diversity.