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Extraction of oil and mineral resources is likely to be the greatest direct human disturbance in the arctic. Although the spatial extent of these disturbances is small, their impacts can be far-reaching because of road and pipeline systems associated with them (Walker et al., 1987). Roads in particular open previously inaccessible areas to new development, either directly related to tourism and hunting or to support facilities for resource extraction.
Changes in goods and services in alpine ecosystems are likely to be dominated by changes in land use associated with grazing, recreation, and other direct impacts, as a result of their proximity to population centers (Körner, 1999; Walker et al., 2001). Many of the alpine zones with greatest biodiversity, such as the Caucasus and Himalayas, are areas where human population pressures may lead to most pronounced land-use change in alpine zones (Akakhanjanz and Breckle, 1995). Direct impacts from human activities are likely to be most pronounced in lower elevational zones that are most accessible to people (Körner, 1999). Improved road access to alpine areas often increases human use for recreation, mining, and grazing and increased forestry pressure at lower elevations (Miller et al., 1996). Overgrazing and trampling by people and animals may tend to destabilize vegetation, leading to erosion and loss of soils that are the long-term basis of the productive capacity of alpine ecosystems.
Alpine areas that are downwind of human population or industrial centers experience substantial rates of nitrogen deposition and acid rain (Körner, 1999). Continued nitrogen deposition at high altitudes, along with changes in land use that lead to soil erosion, can threaten provision of clean water to surrounding regions. Nitrogen deposition occurs primarily during the winter and is transmitted directly to streams during snowmelt, so it readily enters water supplies (Körner, 1999). Many places that use water from alpine areas depend on slow release of the water by melting of snowfields in spring and summer. Warming is likely to create a shortened snowmelt season, with rapid water release creating floods and, later, growing-season droughts. These changes in seasonality, combined with increased harvest in montane forests, would amplify floods.
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