causes of excessive soil erosion. It is most commonly practiced in developing countries in
tropical areas of the world, as people create more land for agriculture.
Grazing animals are animals that live on large areas of grassland (Figure 19.4). They
wander over the area and eat grasses and shrubs. They can remove large amounts of the
plant cover for an area. If too many animals graze the same land area, once the tips of
grasses and shrubs have been eaten, they will use their hooves to pull plants out by their
roots.
Figure 19.4: Grazing animals can cause erosion if they are allowed to overgraze and remove
too much or all of the vegetation in a pasture. ( 11 )
When an area is logged, large areas of trees are cut down and removed for human use
(Figure19.5). When the trees are taken away, the land is left exposed to erosion. Even
moreimportantly, loggingresultsinthelossofleaflitter, ordeadleaves, bark, andbranches
on the forest floor. Leaf litter decreases because no trees are left to drop leaves or other plant
parts to the ground. The leaf litter plays an important role in protecting forest soils from
erosion.
Mining is another activity that speeds up erosion (Figure19.6). When we mine we are
digging in the Earth for mineral resources, like copper or silver. The huge holes dug by
mining operations leave large amounts of ground exposed. In addition, most of the rock
removed when mining is not actually the precious mineral, buttailings, or unwanted rock
that is left next to the mine after the valuable minerals are removed. These tailings are
usually piled up next to a mine, and are easily eroded downhill.
Constructing human buildings and roads also causes much soil erosion. Thisdevelopment
involves changing forest and grassland into cities, buildings, roads, neighborhoods, and other
human-made features. Any time we remove natural vegetation, we make the soil more
susceptible to erosion. In addition, features like roads, sidewalks, and parking lots do not let