|TROPICAL FOREST NETWORK: Biodiversity|
Arctic biodiversityNORTHLANDS: FRAGILE ECOSYSTEMS
Executive Editor: George Clark; Editor: Paul Malamud
U.S. Department of State Office of International Information Programs
Laos. All photos courtesy of Mongabay.com
Biodiversity is at its most luxuriant in tropical areas. Yet, the far northern regions of the globe, while not host to as many species as warm latitudes, nourish and protect an abundant web of living things. Arctic lands demonstrate the ability of life to thrive in the most extreme conditions, by means of ingenious adaptations to climate, light, and nutrition. The Arctic is another elegant example of a self-sustaining, complex -- and endangered -- planetary ecosystem.
Many species of plants and animals live in polar regions -- from minute algae and lichen on bare rocks and ice to spectacular polar bears and falcons. In addition, the Arctic regions provide food and shelter for many migrating bird species from other parts of the world for important parts of their life cycles.
Some Arctic and sub-Arctic areas are rich in oil and minerals. Extracting these natural resources without proper concern for the ecology, conservationists fear, could pose more of a threat to current forms of Arctic life than the cold, snow, and ice. In addition, there is evidence that global warming may be affecting the Arctic climate, with unknown consequences for its fragile biological riches.
The southern part of the Arctic, which lies between the far North and the temperate parts of the planet, is called the sub-Arctic and contains a boreal woodland (named after the Greek god of the north wind, Boreas). Stretching from northwest to eastern Canada, and on to northern Europe and Siberia, it contains larches, spruce, and other conifers. Where the circumpolar timberline comes to an end as it stretches north, the tundra begins -- tundra being a Finnish word for an open plain.
Tundra is open and often saturated with water. While devoid of forests, it is covered with other vegetation. Many tree species that grow in boreal regions continue northwards into the tundra, and there, take the adaptive form of dwarf varieties or shrubs. Underneath the tundra lies permafrost -- a layer of soil that is permanently frozen at all times of year. This keeps moisture from draining out of tundra, so in the summer months, there are plenty of liquid-borne nutrients for life to thrive. To people living in temperate latitudes, the permafrost regions of the world may be best known for preserving the remains of large extinct animals, mammoths, and mastodons. Yet, their living communities fascinate biologists.
Usually, tundra is covered by snow, but in the warm months, an estimated 250 species of moss, lichens, grasses, shrubs, herbs, and sedges resprout. As these plants come to life in the spring, geese, terns, and many other species of birds fly north to nest in dry tundra, thereby making efficient use of the planet's nutrients and open space. The tundra plants take advantage of their short growing season to proliferate, and for a period of time dot their barren environment with bright flowers. Herbivores such as caribou, musk ox, and reindeer feed on plant life; and carnivores, such as wolves, survive by hunting and killing the herbivores. Other tundra denizens include hares, bears, foxes, lemmings, and the ptarmigan, a kind of grouse whose feathered feet protect it from the cold ground. There is also the polar bear, which is considered primarily aquatic, along with seals and walruses. Beluga whales and narwhals swim off the tundra coastline; whitefish, trout, stickleback, char, pike, and salmon thrive in fresh water. Sub-Arctic fauna is even more biodiverse than Arctic fauna.
Some tundra animals such as caribou, reindeer, and the majority of Arctic bird species head south in the fall, leaving the tundra ground to renew itself for the next season. Birds, in particular, migrate extremely long distances, even to South America or regions near the Antarctic. By heading to the North during the summer, migrant animals take advantage of summer light and the high yield of nutrition from plant matter in the short but productive growing season.
Tundra plants survive by adapting to extreme conditions. In the Arctic summer, they tend to grow close to the ground in mats, in order to derive warmth from the soil, and to keep moist rather than exposing themselves to drying winds. In the winter, they are protected by the snow that covers them as they lie dormant. Any animal that inhabits tundra regions during the winter has to be similarly well protected. The musk ox, for example, grows two layers of fur. The willow ptarmigan has water-repellant outer feathers over a layer of inner feathers. It has also learned to dive into snow banks to save itself from extreme cold. The "woolly bear," a kind of caterpillar, freezes solid in the winter, yet thaws out and comes alive in spring due to a kind of anti-freeze in its metabolism that prevents cell damage. Such ingenious adaptations might well one day lead to new understandings of human biology, and new ways to help humans survive.
There is substantial evidence that the Arctic Ocean is warming, based on temperature recordings and observations of melting glaciers. Other environmental issues affecting the Arctic are damage to the tundra from machinery, interference with wildlife migration by construction such as oil pipelines and roads, oil spills, and the fundamental fact that under such extreme conditions nature is slow to repair itself.
Arctic ecosystems are particularly threatened by a group of chemicals known as persistent organic pollutants (POPs). POPs are very stable pesticides, industrial chemicals, and byproducts that can be transported over long distances from sources in temperate regions to the Arctic, where they are more likely to deposit because of colder temperatures. POPs are particularly dangerous because they can accumulate to toxic levels in humans and animals. Some of these chemicals are known or are suspected to cause cancer, perturb development, and reduce fertility in Arctic wildlife. A new global treaty on POPs is expected to reduce their future impact.
Conservation of Arctic regions is a major issue among ecologists, perhaps in part because the Arctic is one of the last untrammeled and unexploited regions of the world.
The Svalbard Archipelago, administered by Norway, is another protected region. The Norwegian government, in a recent report, has determined that "in the event of a conflict between environmental targets and other interests, environmental considerations are to prevail" and calls for "the maintenance of the virtually untouched nature of the environment with respect to continuous areas of wilderness, flora [and] fauna." It also expresses caution about plans to construct a road on the fertile island of Spitsbergen, noting it could "have major landscape and aesthetic consequences" and that "the sparse vegetation and the permafrost make the terrain extremely vulnerable to physical damage."
The Arctic Council, whose members are Canada, Denmark, Finland, Iceland, Norway, Russia, Sweden, and the United States, as well as groups representing indigenous peoples, is attempting to study Northlands environment and work out parameters for habitat protection and conservation on an international scale, while there is still time to protect the Arctic from massive exploitation. It manages a "Program for the Conservation of Arctic Flora and Fauna" called CAFF, and a number of similar programs.
The Nature Conservancy, a not-for-profit organization in the United States, has made an effort to identify biodiversity "hot spots" and conserve them, including some in the North. Kachemak Bay, Alaska, according to the conservancy, contains "a healthy estuary" producing "four to ten times more organic matter than a corn field of the same size." Inventoried species there include sea lions, wintering bald eagles, harbor seals, orca and humpback whales, and about 230 other species of wintering birds, as well as "moose, brown and black bears, wolverines, wolves, otters, and lynx, numerous species of crabs, clams and mussels" and "numerous fish species including all five Pacific salmon, halibut, rock fish and herring."
The Pribilof Islands in the Bering Sea lie near where "currents -- bring nutrient-rich waters to the surface" and foster "extraordinary biological wealth," according to the Nature Conservancy. The Pribilofs help protect "seven great whales -- listed as endangered" and provide breeding grounds for over two million seabirds a year. The islands also host a population of fur seals that "travel as far as 7,000 miles to return to their breeding grounds on the Pribilofs." The Bering Sea is home to over 400 species of fish. Conservation groups are encouraging the U.S. and Russian governments to cooperate in studying the Bering Sea ecosystem and to manage it in a sustainable fashion.
As one moves from the richness of tropical forests northward, biodiversity becomes less luxuriant, but does not become less of an issue. Even in the most barren and frigid Arctic deserts, life is found in the form of microscopic diatoms that cling to ice, and, south of the tree line, it is profuse. Northern seas abound with plankton and marine life. Forms of life compete to wrest nutrition out of the soggy tundra. An ecosystem never exists as a separate entity. The Arctic is intrinsically linked with other global habitats, in ways that are only partly understood.
Benefits of Biodiversity
Traditional crop varieties and food security
The death of global biodiversity
How to save biodiversity
Endangered Forests [page 2]
Biodiversity of Wetlands