Geoscience Reference
In-Depth Information
Siberia, the western Alaska lowlands and interior Alaska, and parts of the Low
Arctic of Canada. Active-layer depths range from 0.4 to 2.0 m in the Low Arctic,
from 0.4 to 1.0 m in the Mid-Arctic, and from 0.25 to 0.9 m in the High Arctic
(Table
8.1
).
8.2.2
Biota
Based on the circumarctic vegetation map of Walker et al. (
2005
) (see Fig.
4.2
)
, the
dominant vegetation types are erect shrub land (25 %), peaty graminoid tundra
(18 %), barrens (12 %), mineral graminoid tundra (11 %), prostrate-shrub tundra
(11 %), and wetlands (7 %). Examples of these vegetation types are given in Fig.
8.1
.
Migrating birds congregate in the circumarctic, especially in wetlands and in the
coastal areas. These birds play an important role locally in pedogenesis. For exam-
ple, Zwolicki et al. (
2013
) showed the effects of guano deposition and nutrient
enrichment in seabird colonies of Spitsbergen. A recent Arctic biodiversity
Fig. 8.1
Common vegetation types in the circumarctic: (
a
) Wet graminoid tundra, Low-Arctic,
Arctic Coastal Plain, Alaska. (
b
) Cryptogam herb barren, High Arctic, northern Greenland. (
c
)
Erect dwarf-shrub tundra. (
d
) Low-shrub tundra, Low-Arctic, Seward Peninsula, Alaska. (
e
) Moist
non-tussock sedge, dwarf-shrub, nonacidic tundra, Arctic Foothills, Alaska. (
f
) Prostrate dwarf-
shrub herb tundra, High Arctic, Axel Heiberg Island, Nunavut, Canada. (
g
) Tussock sedge dwarf-
shrub tundra, Arctic Foothills, Alaska (All photos compliments of D. Walker, Alaska Geobotany
Center, University of Alaska-Fairbanks;
http://www.arcticatlas.org
)
