Mountain Soils - Mountain Geography: Physical and Human Dimensions - page 320

FIGURE 6.9 The black páramo soil of the Ecuadorian Andes, here an andisol above a light-colored
tephra layer in the province of Tungurahua, has a high water-holding capacity. (Photo by C. P.
Harden.)
Most high mountain areas can withstand some grazing, but animals that graze in
herds, especially sheep, goats, or yaks, can rapidly damage an area. Many examples of
the effects of overgrazing in mountains exist. One classic area is in the Mediterranean
region, where after several thousands of years of grazing, hills have little natural veget-
ation and soils are severely eroded. Even in the mountains of the western United States,
after only about two centuries of grazing, evidence of its effects on mountain soils and
vegetation is cause for concern (Milchunas 2006). Fortunately, steps have been and are
being taken to counter this trend. In many higher-elevation areas of public land that
were once freely grazed, grazing is now either regulated or not allowed.
Grazing and cultivation are not the only land uses that promote soil erosion in
mountains. Stormwater and snow-melt runoff from roads and trails on mountain slopes
can erode roads and trails and spill over onto and erode vulnerable surfaces downhill
(Harden 1992, 2001) (Fig. 6.10). As highly compacted surfaces with very low infiltration
capacities, roads and trails generate runoff sooner during a rainstorm and at lower rain-
fall intensities than agricultural fields or forested lands. The significant erosional effect
of roads and trails is a serious concern in mountains where recreation is the dominant
land use, and also where other human activities, such as grazing, agriculture, mining,
or forestry, alter rainfall runoff patterns.
Mountain land use in the countries of Western Europe and North America is now
regulated, but unrestricted use of marginal lands continues in many other areas of the
world. Mountain soils have a limited capacity to support life, but the increasing pres-
sure on mountain lands requires us to learn a great deal more about them and about the
consequences of our actions on them. International attention to mountains and moun-
tain soils is an important step toward better understanding and more sustainably man-
aging the mountain soil resource.