M125 Seward Peninsula Tundra--Meadow Province


Seward Peninsula, 20,600 mi2 (53,400 km2)


Land-surface form.--This area contains extensive uplands of broad convex hills and flat divides 500-2,000 ft (150-600 m) high, cut by sharp V-shaped valleys. Isolated groups of rugged glaciated mountains with peaks 2,500-4,700 ft (800-1,400 m) in elevation reach above coastal lowland and interior basins. The bedrock is chiefly metamorphic, with massive granitic intrusions. Periglacial processes predominate, and ice-wedge polygons are common.

Climate.--The tundra climate is characterized by long, cold winters and short, cool summers. Nome has recorded a minimum temperature of -47F (-44C) and a maximum of 84F (29C). The average January temperature is about 3F (16C), and average temperatures in July are below 50F (10C). Average daily minimum temperatures in winter range from -11 to -2F (-24 to -19C), with an average daily maximum of 3 to 12F (-16 to -11C). Average daily minimum temperatures in summer range from 34 to 43F (1 to 6C), with an average maximum of 55 to 63F (13 to 17C). The growing season is less than 2 months. Fairly heavy snowfall occurs in winter, with even heavier concentrations of rain in summer. Average annual precipitation is about 18 in (460 mm); average annual snowfall ranges from 39 to 78 in (1,000 to 2,000 mm).

Vegetation.--Vegetation exists in moist and wet tundra communities at lower elevations and alpine tundra communities in the high mountains. Vegetation is primarily composed of sedge tussocks interspersed with scattered willows and birches, with isolated spruce-hardwood forests.

Soil.--The Inceptisol soils are generally poorly drained and shallow; the entire peninsula is underlain by permafrost. On hillslopes and ridges they are formed in very gravelly residual material over weathered bedrock. At lower elevations, soils are formed mainly in colluvial and alluvial sediments.

Fauna.--Arctic foxes and Alaska hares are common here, and polar bears are often seen. Ribbon seals are characteristic of areas offshore. Reindeer were introduced at the turn of the century to provide an additional food source for people. Musk ox were introduced in 1970.

Spectacled eiders, ruddy turnstones, and black turnstones are common breeding birds in the lowland tundra of this province. The rare arctic loon, which breeds only in western Alaska, is characteristic of this region. The only known breeding grounds of the very rare bristle-thighed curlew extend throughout this region.