Permafrost

Much tundra has permafrost beneath the surface. Frozen ground restricts deep rooting, while cold conditions slow decomposition and nutrient release. These conditions help explain its low-growing vegetation and relatively low biodiversity.

Heat from buildings and activity around oilfields can thaw permafrost. As the ground becomes unstable, buildings may subside, creating repair costs.

On Arctic tundra, the surface soil thaws during the brief summer, but permafrost remains beneath it. Mosses, lichens, grasses and low-growing shrubs occur here. Arctic fauna include caribou, Arctic foxes, polar bears and seals.