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FIGURE 6 Monumental architecture on Easter Island (Rapa Nui). This
temple site (marae) consists of statues (moai), a platform (ahu), and a
paved court. Photograph courtesy of M. I. Weisler.
order. This can be seen in the distribution of Easter Island
temples, whose placement relates to traditional land unit
boundaries. The size, number, and position of temples
coincide with sociopolitical complexity where human
activities were regulated.
Prominent examples of prehistoric defensive architecture are found along the ridges of Babeldoab on the
Palau Islands in western Micronesia, on the hilltops
of Rapa on the Austral Islands in East Polynesia, and
throughout much of New Zealand. Many fortifications consisted of a series of ditches, embankments, and
palisades that ensured protection from warring tribes.
These sites were built in response to social conflicts that
developed, in part, from increasing populations, low
soil productivity for crop production, and intertribal
competition between late prehistoric social groups. In
essence, fortifications symbolize periods of great social
upheaval.
CONCLUSIONS
The archaeology of the Pacific Islands provides ample
opportunities to investigate many of the important problems in world prehistory, not all of which could be discussed in this short essay. Oceania has some of the earliest
examples of crop domestication, the longest transport of
commodities, some of the most complex chiefdoms in
the world, and certainly the most linguistically diverse
regions on Earth. Modern archaeological research is only
a few decades old in the Pacific, and many exciting and
innovative studies await future generations.
SEE ALSO THE FOLLOWING ARTICLES
Easter Island / Exploration and Discovery / Human Impacts,
Pre-European / Peopling the Pacific / Polynesian Voyaging /
Wallace’s Line
Collerson, K. D., and M. I. Weisler. . Stone adze compositions
and the extent of ancient Polynesian voyaging and trade. Science :
–.
Green, R. C., and M. I. Weisler. . The Mangarevan sequence and
dating of the geographic expansion into Southeast Polynesia. Asian
Perspectives : –.
Irwin, G. . The prehistoric exploration and colonisation of the Pacific.
Cambridge, UK: Cambridge University Press.
Kirch, P. V. . On the road of the winds: an archaeological history of
the Pacific islands before European contact. Berkeley: University of
California Press.
Rainbird, P. . The archaeology of Micronesia. New York: Cambridge
University Press.
Weisler, M. I., ed. . Prehistoric long-distance interaction in Oceania:
an interdisciplinary approach. New Zealand Archaeological Association
Monograph . Auckland: New Zealand Archaeological Association.
Weisler, M. I. . Hard evidence for prehistoric interaction in Polynesia.
Current Anthropology : –.
ARCTIC ISLANDS,
BIOLOGY
INGER GREVE ALSOS
University Centre of Svalbard, Longyearbyen, Norway
LYNN GILLESPIE
Canadian Museum of Nature, Ottawa
YURI M. MARUSIK
Institute for Biological Problems of the North, Magadan,
Russia
Arctic islands constitute a major part of the arctic land
masses. Low temperatures and short summers are strong
environmental filters that exclude most organisms from
living there. Thus, the diversity of most species groups is
lower on arctic islands than on the arctic mainland and
more southern latitudes. Arctic species exhibit many different adaptations to cope with these harsh environmental
conditions.
EFFECT OF PAST AND PRESENT CLIMATE ON
PATTERNS OF BIODIVERSITY AND ENDEMISM
Repeated periods of glaciation during the Pleistocene
have strongly influenced the biota of arctic islands.
During the Last Glacial Maximum (LGM; about
, years ago), major ice caps wiped out most
species in the Canadian Arctic Archipelago (CAA),
Greenland, Novaya Zemlya, Severnaya Zemlya, Franz
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Gillespie08_A.indd 47
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St. Lawrence
Wrangel
Novosibirskiye
Canadian Arctic
Archipelago
Zevernaya
Zemlya
Franz Josef
Land
Novaya
Zemlya
Greenland
Svalbard
Jan Mayen
Bioclimatic zones:
A Arctic polar desert (1-3 oC)
o
B Northern arctic tundra (4-5 C)
o
C Middle arctic tundra (6-7 C)
o
D Southern arctic tundra (8-9 C)
o
E Arctic shrub tundra (10-12 C)
Current glaciers
Last Glacial Maximum (LGM)
Bering Land Bridge during LGM
Ice-free uplands/nunataks during LGM
FIGURE 1 Bioclimatic zones (http://www.arcticatlas.org/maps/catalog/
index.shtml) and glaciations of Arctic islands.
St. Lawrence
Ayon
Chetyrekhstolbovoy
Wrangel
Bol’shaya Lyakhovskiy
Genriyetta
Kotel’nyy
Bennetta
Banks
Victoria
Bolshoi Begichev
Parry
Prince of Wales
Andreya
King William
Somerset
Ellef Ringnes
Cornwallis
Axel Heiberg
Devon
Ellesmere
Southampton
Oktyabr’skov Revolyutsii
Troynoy Dickson
Uyedineniya
Brekhovskiye
Sverdrup
Sibiryakova
Belyy
Franz Josef
Novaya Zemlya N
Vize
Coats
Baffin
Russkiy
Pioner
N Greenland
Novaya Zemlya S
Total Greenland
Svalbard
W Greenland
E Greenland
S Greenland
Jan Mayen
FIGURE 2 Vascular plant (red bars) and springtail (Collembola, blue
hypothesis), or became locally extinct and later recolonized from areas outside the main ice caps (tabula rasa
hypothesis). Although a few molecular studies have
found support for the glacial survival hypothesis, no
paleorecords support continuous in situ existence of life
within the glaciated islands.
In contrast, the islands and areas around the Bering
Strait (Beringian islands such as Novosibirskiye Ostrova,
Wrangel, St. Lawrence, and Diomede) remained unglaciated throughout the Pleistocene. The lowered sea levels
during glacial periods resulted in a large shelf area connecting present-day islands with the Russian and Alaskan
mainland (the Bering land bridge). These altering connections to the mainland, and the Beringian islands remaining unglaciated, have strongly influenced both speciation
processes and distribution of species on these islands. The
number of endemic species is larger on Beringian islands
than on other arctic islands and the diversity of vascular
plants and springtails on, for example, Wrangel Island is
extremely high (Fig. ).
The current summer temperatures of the warmest
month range from – °C in the arctic shrub tundra zone to – °C in the arctic polar desert zone. The
polar desert and northern Arctic tundra zones are almost
exclusively found on arctic islands. Within a geographical region, summer temperature is the environmental variable that best predicts the diversity of species.
For example, the number of vascular plants decreases
towards the north in the Canadian Arctic Archipelago
and from Novaya Zemlya to Franz Josef Land in Russia.
However, some exceptions exist. In bryophytes, species
diversity depends more on substrate than on temperature, and thus the difference in species numbers between
north and south Greenland is low.
Although the total number of species decreases towards
the north or with lower temperatures, the proportion
of widespread species increases. Of  taxa of vascular
plants found in the arctic polar desert zone, .% occur
in both North America and Eurasia, and only one species
is endemic to a region. Similarly, in the small arthropods
known as springtails, the proportion of widespread species is highest in previously glaciated, high arctic islands.
bars) diversity on arctic islands. Data compiled from various sources.
The bar for total species of vascular plants in Greenland represents 515
species. The bars for springtails have been doubled to visualize them.
ISLAND GROUPS
Svalbard and Jan Mayen
Josef Land, and Svalbard (Fig. ). Some ice-free nunataks and uplands existed, however, and it is debated
whether some plants and animals survived the periods of glaciation (glacial persistence or glacial survival
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Gillespie08_A.indd 48
The Svalbard archipelago is situated from ° to ° N
and from ° to ° E. The land area is , km, but
about % of this is covered by glaciers. The influence of
the warm North Atlantic Current gives a more oceanic
ARCTIC ISLANDS, BIOLOGY
4/13/09 3:00:24 PM
TABLE 1
Dwarf Birch
(Betula nana)
A
Estimated Numbers of Different Species Groups
3
Canadian
Arctic
2
Size (km )
Ice-free area
Vascular plants
Mosses
Liverworts
Fungi
Lichens
Terrestrial
mammals
Marine mammals
Birds (regularly
nesting)
Freshwater fishes
Wrangel
Archipelago
Greenland
Svalbard
Island
1,420,000
1,260,000
349
346
—
—
>750
11
2,170,000
410,000
515 (32)
477
135
1600
1094
8
61,000
24,000
165 (4)
288
85
624
764 (12)
2 (1)
7,600
7,608
417 (23)
239
87
—
350
3 (2)
7
61
22
58
8
38
12
47 (1–3)
10
3
1
0
41
9
Mountain Avens
(Dryas octopetala)
B
11
note: Data are for Canada (various sources), Greenland (Jensen and Christensen
2003), Svalbard (updated from Elvebakk and Prestrud 1996; Prestrud et al. 2004),
and Wrangel Island (Stishov 2004). Estimated numbers of endemic species are
given in parentheses. Note that differences in degree of exploration and as well as
taxonomical view make the numbers inaccurate.
and warmer climate compared to other islands at this latitude. This is also reflected in the species diversity, which
is comparatively high in Svalbard (Table ).
Svalbard was almost entirely glaciated during the last
glacial maximum, and paleorecords show a sparse arctic
vegetation subsequent to , years ago. Although this
is one of the most remote arctic archipelagoes, molecular analyses of plant species show that it was repeatedly
colonized during the Holocene from several source areas
(Fig. ). The main source areas were in northern Russia/
Siberia and northeastern Greenland, areas connected to
Svalbard by winter sea ice. Thus, sea ice, probably in
combination with wind, might be an important dispersal
mechanism to arctic islands. Exceptionally warm winds
may also carry insects directly from areas such as Russia to
Svalbard, as was observed for the nonresident migratory
diamondback moth Plutella xylostella. The few endemic
species or subspecies in Svalbard (i.e., the Svalbard reindeer, the Svalbard aphid, and four plant species) have
probably evolved recently from species that immigrated
after the LGM.
In contrast to most arctic islands, there are no rodents
on the archipelago (except the locally introduced sibling
vole). The main herbivores are geese and reindeer. The
arctic fox feeds mainly on eggs and chicks of sea birds and
1
67
2
White Arctic Bell-heather
(Cassiope tetragona)
C
4
1
6
45
D
Bog Bilberry
(Vaccinium uliginosum)
12
76
FIGURE 3 Source regions for past colonization of (A) dwarf birch
(Betula nana), (B) mountain avens (Dryas octopetala), (C) white arctic bell-heather (Cassiope tetragona), and (D) bog bilberry (Vaccinium
uliginosum) to Svalbard. Source regions are inferred from genetic
data (amplified fragment length polymorphism). Colors represent
main genetic groups, and symbols represent sub-groups. Numbers on
the arrows are percentages assumed to have arrived from the source
region. The geographic distribution of the species is shaded. Reproduced with permission from Science.
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geese, as well as carcasses of seals and reindeer. There are
many seabirds breeding in the archipelago, and these contribute a significant input of nutrients for plant growth.
The only resident bird is the Svalbard ptarmigan (Lagopus mutus hyperboreus), which is endemic to Svalbard and
Franz Josef Land.
Jan Mayen is a small ( km) volcanic island east of
Greenland. It has an extremely oceanic climate with mild
winters and relatively cold and wet summers. About twothirds of the  vascular plant species found there are circumpolar, whereas the other third is amphi-Atlantic. The
only endemic species found are apomictic dandelions
(Taraxacum). The arctic fox is the only terrestrial mammal on the island. Large seabird colonies are found during the summer, but only the fulmar (Fulmarus glacialis)
stays during winter.
Greenland
Greenland is the world’s largest island. Including the
numerous smaller islands along the shore, its total size
is . million km. The majority of species are confined
to the ice-free margins, which cover only approximately
, km. Greenland stretches from °′ N to almost
° N and spans a vegetation gradient from birch forest in
the south to polar desert in the north (Fig. ).
Considering the large size of Greenland, species diversity is relatively low, and it decreases from south to north
as, for example, in vascular plants. Also, there are only a
limited number of species that are endemic to Greenland.
Of the total  vascular plant species,  taxa are endemic.
However,  of the endemics belong to the apomictic
hawkweed genus (Hieracium), which rapidly evolves new
FIGURE 4 Low-stature vegetation with prostrate or cushion-formed
herbs such as moss champion (Silene acaulis) dominate the middle
arctic tundra zone. Ammassalik district in southeastern Greenland.
Photograph by Inger Greve Alsos.
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Gillespie08_A.indd 50
species. Endemic species of algae and three spider species
have also been recorded, and a few bird subspecies breed
only in Greenland, but they overwinter elsewhere.
The relatively low diversity and endemism found in
this large island are probably due to its glacial history.
Ice-free areas existed in Greenland throughout the glacial
period, but according to climate data derived from ice
cores, it was so cold during the LGM that only the most
cold-adapted species could have survived there. Thus, it
is assumed that the majority of species colonized Greenland during the last , years. This view is supported
by molecular studies of several plant species. A large proportion of Greenland’s plants and animals are also found
in northwestern Europe, indicating that they arrived from
there. Although this distance is long, the Faroe Islands
and Iceland form steppingstones along the route. Further,
the majority of Greenlandic birds migrate from Europe
and could have transported seeds, spores, and even some
invertebrates. The majority of spiders and some groups
of insects are Nearctic, indicating a high proportion of
immigration also from northeastern Canada.
Canadian Arctic Archipelago
The Canadian Arctic Archipelago (CAA) covers an
immense area, ∼. million km, and comprises numerous large and many more smaller islands. It extends about
 km from below the Arctic Circle to the northern tip
of Ellesmere, and  km east-west from Baffin to Banks
Islands. Ice caps occur in the mountainous northern and
eastern parts on Axel Heiberg, Ellesmere, Devon, and
Baffin Islands (maximum elevation  m), but overall,
glaciers cover only about % of the archipelago. Thus,
the ice-free area of CAA is three times as large as the icefree area of Greenland and more than  times as large as
the ice-free area in Svalbard.
Recolonization after the LGM occurred primarily
from mainland areas to the south, a distance as short as
– km at several locations. Unglaciated Beringia was
also an important source area for many groups, contributing to east-west differences in species composition
(e.g., higher diversity of legumes on Banks and Victoria
Islands). Glacial refugia on Banks Island provided additional source areas, while postulated refugia on Ellesmere
and other islands have yet to be confirmed.
Considering its large land area, species diversity is low
on the Canadian Arctic Archipelago. The strong southto-north decrease in diversity is correlated with summer
temperature and distance from the mainland. However,
topography and oceanic influences modify this gradient,
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4/13/09 3:00:26 PM
creating a more complex pattern. Rain shadow effects
are responsible for warmer drier summers and the relatively high diversity of the “polar oases” of the Forsheim
Peninsula and Lake Hazen area on Ellesmere Island. Cool
summers with extensive cloud and fog are responsible for
the low vascular plant and arthropod diversity on Ellef
Ringnes and nearby islands. Located north of the “shrub
line,” this barren region lacks woody plants, which are so
characteristic of tundra vegetation (e.g., willows, mountain avens, Ericaceae).
No endemic vascular plants, bryophytes, lichens, mammals, or arthropods are known from the CAA, but several
species are confined to the Archipelago and Greenland,
such as Peary caribou, the alkali grass Puccinellia bruggemannii, the moth Gynaephora groenlandica, and the wolf
spider Alopecosa exasperans. Also, at least one undescribed
species of spider has been found on Banks Island.
Russian and Beringian Islands
The Russian arctic islands can be divided into five main
groups: () Novaya Zemlya (“New Land”) with adjacent
Vaigach, Kolguyev, and some smaller islands; () Franz
Josef Land; () Severnaya Zemlya (“North Land”);
() Novosibroskiye Ostrova (“New Siberian Islands”);
and () Wrangel and Gerald Islands. Besides these main
groups there many small islands at the Ob’, Yenisei,
Kheta, Lena, and Kolyma deltas and near Taimyr Peninsula. In addition, there are several arctic islands belonging
to Russia and the United States in the Bering Strait and
Bering Sea (e.g., St. Lawrence, Yttygran, Arakamchechen,
Diomede and King Island).
The most biologically diverse and well studied island
in the Russian Arctic is Wrangel Island. It is a remote, relatively small island of about , km, with the highest
elevation above  m. A unique feature of this island
is the very limited extent of Pleistocene glaciations combined with the lowered sea level during LGM, making
Wrangel a part of the Bering land bridge. This has enabled
enrichment of the fauna and flora by very different elements originating in boreal, forest-tundra, tundra, arctic
polar desert, and even steppe zones from Asia as well as
North America, which has resulted in a species composition on Wrangel Island different from those on all other
islands. For vascular plants,  species are known, more
than for the whole CAA ( species) and the northwest
sector of the Siberian arctic ( species), and approaching that of Taimyr Peninsula () and Greenland ().
Similarly, the diversity of spiders, beetles, and birds is high
on Wrangel Island compared to Svalbard and Greenland.
The diversity of many insect families and orders is higher
than on any other arctic island, including Greenland.
The recurrent connections and disconnections of
Wrangel Island also led to speciation in mammals, vascular plants, and some groups of arthropods. The number
of endemic species on the island is extraordinarily high
for the Arctic in general and for arctic islands particularly.
There are  endemic vascular plant species, four spider
species, % of weevils, both of the rodents Dicrostonyx
groenlandicus vinogradovi and Lemmus sibiricus portenkoi
(Fig. ), and at least one bird subspecies Cepphus grylli
tajani. If the recently ( years old) extinct dwarf
mammoth is counted, the level of endemism of mammals would be higher. In the late Pleistocene several other
ungulates such as Przewalski’s horse, woolly rhinoceros,
primeval bison (Bison priscus), musk ox, woolly mammoth, and reindeer occurred on the island.
The Novosibroskiye Ostrova (New Siberian Islands)
consists of two larger groups of islands, Lyakhovsky and
Anzhu, and one small group called De-Longa. With its
area of about , km, this region is about five times
larger than Wrangel Island, and like Wrangel, it was also
unglaciated and connected by the Bering land bridge.
However, the archipelago is rather flat, which limits
habitat diversity, and the diversity of plants, springtails,
birds, and beetles is less than on Wrangel. There are some
species on Novosibroskiye Ostrova that do not occur
on Wrangel, including a willow grouse species and two
goose species. The mammal fauna consist of wolf, wild
reindeer, one lemming species, and arctic fox. The fossil
mammoth fauna is even richer than on Wrangel Island
with additional species such as saiga antelope, cave lion,
and voles. Also, the fossil beetle fauna is much richer
FIGURE 5 Portenkoi’s lemming, Lemmus sibiricus portenkoi, endemic
to Wrangel Island, has an important role in the ecosystem. Photograph
by Igor Dorogoi.
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(about  species during the past , years, or 
species during last , years) than the present beetle
fauna (about  species). In the nineteenth and beginning of the twentieth centuries, digging up and selling
ivory from fossil mammoths was a profitable business.
The Severnaya Zemlya Ostrova consist of four large
(October Revolution, Bolshevik, Komsomolets, Pioneer)
and about  smaller islands, covering a total area of
about , km. Although the island group remained
partly unglaciated throughout the Pleistocene, it was not
connected by the Bering land bridge, and it is also situated rather far north. Thus, species diversity is lower than
on most other Russian archipelagoes with, for example,
about  species of vascular plants. Only  of the  bird
species that have been observed on the islands breed there.
Six terrestrial mammals are known there: lemming, arctic
fox, wolf, ermine, arctic hare, and reindeer. Four species
of beetles have been found on the archipelago, but only
on the southernmost island.
The Novaya Zemlya Archipelago consists of two large
and several smaller islands, in total about , km. The
number of vascular plants and springtails is similar to that
on many other islands that have been previously glaciated. The flora represents a transition between the arctic Europe and Asia but with a separate mountain range
element connected to the Urals. Some endemic vascular
plants in Novaya Zemlya have been proposed, but they
are dubious. There are two lemming species, a local reindeer subspecies, and arctic fox on the archipelago.
Franz Josef Land (, km) is the northernmost
archipelago and consists of almost  islands. Glaciers
cover % of the archipelago. It is the most species-poor
arctic archipelago, with only about  vascular plant
species, about  bryophytes, over  lichens, one terrestrial mammal (arctic fox), at least  springtails, two
spiders, and no beetles. Only  bird species breed on
the island, but almost  other bird species have been
observed visiting.
Aleutian Islands
The Aleutian and Commander Islands are a ,-km long
archipelago to the south of the Arctic, separating the Bering Sea from the North Pacific Ocean. Although the U.S.
government includes this archipelago in its definition of
the Arctic because of the treeless landscape that prevails
here, this is caused largely by strong winds rather than low
temperatures and short growing season, as is the case in
the Arctic. These islands serve as a natural bridge between
Old World and New World flora and fauna, although
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FIGURE 6 The sedge Carex bigelowii ssp. arctisibirica in Svalbard.
Most sedges have clonal growth and can become very old; up to
3000-year-old clones have been found in the Arctic. Photograph by
Inger Greve Alsos.
physical evidence suggests that this archipelago was under
ice during the LGM, so terrestrial species on these islands
should be recent colonists (i.e., since the last glaciation, or
less than , years ago). However, the relatively high
levels of endemism (for high-latitude organisms) that characterize the Aleutian and Commander Islands suggests that
many of these taxa were isolated for longer periods of time,
probably in “cryptic” glacial refugia: ice-free areas that harbored multiple taxa through the Quaternary glacial cycles,
though so far only evident through the biological record.
Moreover, natural selection has resulted in local adaptations to the harsh conditions of the islands, with evidence
of traits such as increased body size in some bird species.
In the same way, the Alexander archipelago, a chain of over
 islands off the southeastern coast of Alaska that is also
recently glaciated, though currently covered by evergreen
forest and even temperate rain forest, is characterized by
a number of monophyletic lineages, which may be attributed to multiple Holocene invasions or the persistence of
taxa in refugia during Pleistocene glacial advances.
CHARACTERISTICS OF SPECIES
Plants
The arctic flora ranges from shrub tundra in the south to
almost barren polar desert, where no woody plants live and
only scattered herbs, bryophytes, and lichens are found.
The majority of species are long-lived perennials with
ARCTIC ISLANDS, BIOLOGY
4/13/09 3:00:26 PM
relatively low resource allocation to sexual reproduction
and high reliance on asexual reproduction for population
maintenance, but a high variety of life strategies exists.
There are fewer pollinators and lower pollinator activity
in the Arctic than in other regions. Plant species adapted
for wind pollination are dominant, and self-pollination
is common. The growth forms are often prostrate mats,
tussocks, rosettes, or cushions, which reduce desiccation
and mechanical damage from the strong wind and maximize heat absorption (Fig. ). In addition to the low temperatures and short growing season, drought places a very
significant stress on plant life. The majority of bryophytes
and lichen species are well adapted to periods of drought
and increase both in abundance and ecosystem importance northwards.
Invertebrates
Invertebrate groups occurring on arctic islands have
evolved from species in the boreal biome, where winter
temperatures are often lower than in the tundra zone, and
they have similar adaptations to cold resistance as boreal
species. The main limiting factor for invertebrates is heat
deficit in the short (– month), cool growing season,
and therefore the main adaptations are directed towards
shortening of the life cycle (vivipary, reduction of size)
or extension of the life cycle to several years. They survive the winter by producing cryoprotectors, being able
to dehydrate, or overwintering as cold-resistant eggs.
In addition, behavioral strategies may assist in avoiding
low-temperature extremes, for example seeking protected
places to avoid winter cold, such as under thick snow
cover or close to non freezing water currents.
In arthropods, adaptations to the arctic climate lead to
dominance by small-sized groups such as mites, spiders,
and springtails, which have relatively high species diversity on arctic islands. Large sized insects, such as large
ground beetles and bumblebees, are lacking on most arctic islands, whereas beetles and some other megadiverse
groups, such as moths and true bugs, are represented on
arctic islands by fewer species than small-sized groups.
There is a decrease in species numbers of herbivorous
insects (especially among beetles, butterflies, moths, and
true bugs) in comparison to predaceous ones.
FIGURE 7 In the Arctic, many animals are white in winter and brown
during summer, which gives them a good camouflage. In the High
Arctic some animals, such as this arctic hare on Ellesmere Island,
remain white year-round, an adaptation to the very short snow-free
summer period. Photograph by Lynn Gillespie.
high as  °C. Larger arctic animals have developed thicker
and denser fur or plumage or a thick fat/blubber layer to
keep warm without spending much energy. Smaller animals such as lemmings and voles live mainly under the
snow, which acts as a thick insulating layer. Ptarmigans
stay in “dock” (under snow) during bad weather conditions to reduce heat loss. The blood circulation system
is also adapted to minimize heat loss by countercurrent
heat exchange and by slowing down the circulation to
extremities. Many arctic mammals have enlarged nasal
cavities, and circulatory adjustments in the nose reduce
water and heat loss. Some arctic animals, such as the Svalbard reindeer and ptarmigan, store large amounts of fat
during the summer and autumn season, which is used
to survive the winter (Fig. ). Most arctic birds species
migrate south before the winter period. When they arrive
Mammals and Birds
To survive the harsh winter of the Arctic, mammals and
birds have developed morphological, physiological, and
behavioral adaptations (Fig. ). The difference between
ambient temperature and body temperature may be as
FIGURE 8 Many arctic mammals, such as the Svalbard reindeer, put on
large fat reserves during the autumn. Photograph by Inger Greve Alsos.
ARCTIC ISLANDS, BIOLOGY
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on the breeding ground in spring, their breeding success
is closely linked to the timing of breeding relative to snow
melt and peak food production.
HUMANS ON ARCTIC ISLANDS
Humans have long been a part of the arctic environment,
intimately connected to the local resources on land and
sea. The indigenous peoples harvest natural resources
both from the terrestrial (arctic fox, ptarmigan, reindeer,
caribou, musk ox) and the marine environment (fish,
whale, seal, polar bear; Fig. ). In Greenland, fishing is
the all-dominating trade and accounts for % of total
exports, but in the hunting districts of the outlying areas
the seal and whale catch is of great importance and forms
a stable existence for one-fifth of the Greenlandic population. Reindeer herding is of local importance only on few
arctic islands, such as in northernmost Norway.
The  communities in the CAA are mainly inhabited
by Inuit. Most Russian arctic islands are not inhabited
except by the staff of small military camps, nature reserve
stations and weather stations, but indigenous people live
on some islands; for example, some Nenet families live
on Novaya Zemlya. Fifty-seven thousand people, predominantly Inuit, live in towns and small settlements on
Greenland. In Svalbard there is one Norwegian settlement
with around  inhabitants and one Russian settlement
with about  inhabitants. Industrial activity is found
only on a few arctic islands, such as mining activities
in Svalbard, on Kolguyev, and, until recently, on Little
Cornwallis and Baffin Island. There are huge reserves
of oil and gas on arctic islands and the surrounding sea
floor, such as the Sverdrup Basin in the Canadian high
arctic, and exploration drilling is done in several locations.
Tourism and research activities are increasing on some
arctic islands such as Svalbard and Baffin.
CONSERVATION OF ARCTIC
FLORA AND FAUNA
The arctic flora and vegetation are vulnerable to physical disturbance, and vehicle tracks often last for decades.
Humans have overexploited many species, such as whales,
polar bear, and arctic fox. Although some species and
populations have recovered, others are still threatened.
Long-range pollution from the industrial part of the
world, such as heavy metals, persistent organic pollutants
(POPs), and radionuclides, has reached arctic islands, and
such pollutants are accumulating in some organisms. Climate change is predicted to be of higher magnitude in the
Arctic than in other places in the word. Because the arctic islands represent the “end of land,” high arctic species
have no further place to migrate if they are outcompeted
by more southern species, and they may thus become
extinct. Global warming will also open up the northern
sea routes both in Canada and Russia and make the arctic
oil and gas reserves more accessible, which would potentially lead to increased pollution and disturbance.
Knowledge necessary for conservation is lacking for
many islands, species, and ecological processes in the
Arctic. For example, the identification and classification
of arctic invertebrates, fungi, bryophytes, and microorganisms is limited. Although some monitoring programs
exist, information on the status and trends of arctic
populations is fragmentary. For proper management in
a changing climate, more knowledge is needed about the
species found on arctic islands, the ways they interact,
and how they respond to the changing physical environment, especially climate.
SEE ALSO THE FOLLOWING ARTICLES
Arctic Islands, Geology / Global Warming / Mammal Radiations /
Refugia / Whales and Whaling
FURTHER READING
FIGURE 9 Inuit hunters skinning a seal in Grise Fiord, Ellesmere Island,
Canada. Photograph by Olivier Gilg.
54
Gillespie08_A.indd 54
Aiken, S. G., M. J. Dallwitz, L. L. Consaul, C. L McJannet, L. J. Gillespie,
R. L. Boles, G. W. Argus, J. M. Gillett, P. J. Scott, R. Elven, and M. C.
LeBlanc. . Flora of the Canadian Arctic Archipelago. Ottawa: NRC
Press (CD-ROM).
Born, E. W., and J. Böcher. . The ecology of Greenland. Nuuk, Greenland: Ministry of Environment and Natural Resources.
Conservation of Arctic Flora and Fauna. . Arctic flora and fauna.
Status and conservation. Helsinki: Edita.
Chapin, F. S. III, and C. Körner. . Arctic and alpine biodiversity: pattern, causes and ecosystem consequences. Berlin: Springer-Verlag.
Danks, H. V. . Arctic arthopods: a review of the systematics and ecology
with particular reference to the North American fauna. Ottawa: Entomological Society of Canada.
ARCTIC ISLANDS, BIOLOGY
4/13/09 3:00:28 PM
ES
ALASKA
RI
DG
Banks
Is.
Severnaya
Zemlya
AL
PH
A&
M
M
O
EN
RI N
DE
D OS
G O
LE
E
V
V
Victoria
Is.
CHUKCHI
PLATEAU
AMERICA
Siberia
Franz
Josef
Land
LO
Elvebakk, A., and P. Prestrud. . A catalogue of Svalbard plant, fungi,
algae and cyanobacteria. Norsk Polarinstitutt Skrifter .
Jensen, D. B., and K. D. Christensen. . The biodiversity of Greenland—a country study. Technical report. Pinngortitaleriffik: Grønlands
Naturinstitut (Greenland Institute of Natural Resources).
Kristinsson, H., E. S. Hansen, and M. Zhurbenko. . Panarctic lichen
checklist. Conservation of Arctic Flora and Fauna. http://arcticportal
.org/en/caff/.
Prestrud, P., H. Strøm, and H. V. Goldman. . A catalogue of the terrestrial and marine animals of Svalbard. Norsk Polarinstitutt Skrifter .
Stishov, M. S. . [Wrangel Island—master pattern of nature and nature
anomaly.] Yoshkar-Ola: Mariyski Printing Factory Press (In Russian).
Baffin
Is.
Ellesmere Is.
Novaya
Zemlya
Svalbard
EU R A S I A
GREENLAND
Scandinavia
ARCTIC ISLANDS,
GEOLOGY
FIGURE 1 Plate tectonic reconstruction of the Arctic as it is believed
to have appeared approximately 70 million years ago prior to opening of the Arctic, North Atlantic, and North Pacific oceans. (Reprinted
MICHAEL J. HAMBREY
Aberystwyth University, United Kingdom
The geological history of the Arctic spans nearly four billion years and includes some of the oldest rocks on Earth.
A vast range of sedimentary, igneous, and metamorphic
rocks are present, but few were formed in their current
position. The geological record for many Arctic islands
reflects the drift of fragments of continental crust from a
position south of the equator to their current polar position. As a consequence, the rocks record a range of climates
from tropical to glacial, as well as a fascinating glimpse of
biological evolution from the algae of the Precambrian to
the high-order animals and plants of today.
TECTONIC EVOLUTION
By outlining the tectonic components and history of the
whole Arctic region, a context is provided for the main
phases of geological evolution of the region. The geological
attributes of the Arctic islands reflect the disparate nature
of individual continental fragments and their movement
by plate tectonic processes through time. These processes
involved continental breakup, continental collision, and
sea floor spreading. Indeed, many parts of the Arctic have
rocks that once were formed south of the equator; plate
movements have resulted in their slow progression to a
northern polar position today. All the continental fragments are believed to have been united as one supercontinent about  million years ago (Fig. ). Since then, the
Arctic Ocean basin has opened, along with the North
Pacific Ocean, Baffin Bay, and the Norwegian-Greenland
Sea. The oldest rocks are Archean to Proterozoic meta-
with permission of Cambridge University Press from Dowdeswell and
Hambrey 2002: 32, adapted from Worsley and Aga 1986.)
morphic rocks that represent stable crystalline shields. In
many areas they are overlain by sedimentary rocks. Periodically, the sedimentary strata were intruded by igneous
rocks, subjected to metamorphism deep in the crust, and
deformed during mountain-building events or “orogenies,” when continents collided. The sedimentary strata
reflect the climatic regimes and topographic/bathymetric
settings under which they formed, including under ice
age, temperate, and tropical climates and deep-sea, continental shelf, fluvial, glacial, estuarine, and mountain
environments.
This pattern of northward drift has been determined with a reasonable degree of certainty over the
past  million years, especially for Svalbard and East
Greenland. Ongoing tectonic processes are focussed on
the continuing opening of the North Atlantic. New
oceanic crust continues to form along the Mid-Atlantic
Ridge, upon which the volcanic islands of Iceland and
Jan Mayen are located, surrounded by deep ocean. New
basaltic rocks formed on the ridge continue to push
Europe away from Greenland and North America,
a process that began about  million years ago. In
contrast, continental margins are “passive” and thus
relatively stable today, lacking significant earthquake
activity.
The other main plate tectonic process, continental
collision, is not a feature of the Arctic at the presentday. However, the older geological record shows dramatic evidence of this process on several Arctic islands.
The “Caledonian Orogeny” of the early Paleozoic Era
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