Environmental Management: Principles and practice
Alpine and high latitudes
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5 2020 03 04!03 12 11 PM
Alpine and high latitudes
In both the Old and New Worlds there has been considerable development of high- altitude environments. World-wide, mountain (or alpine) environments have attracted tourism. High-altitude and high-latitude ecosystems are subject to extreme conditions, not just low temperature but also high winds. Mountains experience marked diurnal temperature fluctuations, high levels of UV radiation, wind exposure and drought; high latitudes suffer all three, plus they may have permafrost soils which impede drainage of summer melt and are prone to cryoturbation (frost movements), and daylength varies by season, with prolonged winter darkness (Bliss et al., 1981). These areas cover a considerable portion of the Earth’s land surface and their vegetation and soils are sensitive to disturbance, are likely to be slow to recover, and may have a relatively low species diversity. With vegetation and soils under stress, mountain and high-latitude areas are vulnerable to transboundary pollution, especially acid deposition (Figure 10.1). A number of mountain environments have experienced considerable population increase in recent decades, leading to forest, pasture and soil degradation. In Europe and the Rockies of the USA, cross-mountain highways spread vehicle exhaust emissions into high passes where it may directly cause pollution or produce (tropospheric) ozone which damages vegetation—some countries have tried to force traffic off mountain roads to try to halt damage to alpine forests. Disturbance of FIGURE 10.1 Alpine resort of Cervinia (Matterhorn mid-background). The slopes are subject to pressures from winter ski activity, car traffic reaches as high as 2,300 m above sea-level (foreground), and there is considerable hotel and chalet construction CHAPTER TEN 196 mountain ecosystems may impact on lower altitudes through avalanches, landslides and altered streamflow (see Figure 10.2). In mountain ecosystems managers tend to adopt a valley, watershed or micro-watershed approach to ensure an integrated view of higher and lower slopes (livelihood strategies often operate at several altitudes). There has been less population growth in high latitudes than mountains, although there are cities in Canada, Alaska, Norway, Finland and Russia, and military and resource development activity. Any traffic across permafrost during the summer is likely to result in damaged vegetation and soil that will be slow to mend. In winter, alpine and tundra regions are less likely to suffer soil compaction and ground vegetation damage. However, plants emerging from the snow, such as young trees, are easily damaged by skiers and skidoos, and snow compaction may delay spring thaw and cause problems for wildlife. At high latitudes pollution may break down slowly, so oil spills are a problem. Radioactive fallout can become concentrated in lichens and bryophytes, affecting grazing animals. Alaska, Canada, Scandinavia, Greenland, Spitzbergen, Iceland and Russia have oil and gas, and other mineral development in tundra regions (e.g. the Trans-Alaska Pipeline) and so far have managed environmental impacts quite well (Williams, 1979; Copithorne, 1991). Northern high latitudes have experienced considerable social and technological change: the hunting and transport practices of indigenous people have altered, notably with the adoption of motor boats, skidoos and firearms. There has also been pressure FIGURE 10.2 Overgrazed land and poorly maintained terraces, High Atlas Mountains, Morocco. As vegetation is degraded at higher altitude, landslides, silted streams and erratic streamflow disrupt farmland and irrigation at lower altitudes DIFFICULT SITUATIONS 197 from some NGOs for change in traditional hunting practices (Berg, 1969). The end of the Cold War and better scientific equipment and vehicles have facilitated study, monitoring and exchange of data, assisting northern high-latitude management (Perkins, 1995). Disposal of waste presents problems at high latitude and in alpine areas. In Antarctica regulations now strictly control waste disposal and most is returned to lower latitudes for disposal (Harris and Meadows, 1992). Some mountain areas have growing waste problems, mainly associated with tourism and climbing activity, notably the Himalayas. Polar seas are vulnerable to pollution because of the slow growth of organisms and slow decay of pollutants and also as a consequence of ice cover, which can restrict mixing of water masses and trap pollutants; the risk of spills is increased by the movement of icebergs, which can damage oil extraction and other infrastructure. There have been marine oil spills near Antarctica and Alaska, e.g. the Exxon Valdez disaster. The CIS has a problem with radioactive waste dumping in the Barents Sea and other Arctic waters, and with radioactive contamination from military facilities along the northern seaboard. These are likely to be expensive to manage and are strategically sensitive. There are virtually no tundras in the high southern latitudes, but there are extensive peat bogs and swamps in southern South America, the Falkland Islands, and on some sub-Antarctic islands. These peatlands and the southernmost forests of Tierra del Fuego share many of the vulnerabilities of northern tundra and alpine areas. Sub-Arctic and sub-Antarctic islands have some of the problems of both high- latitude environments and island isolation. Download 6.45 Mb. Do'stlaringiz bilan baham: |
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