Allowing livestock to graze along river banks can damage salmon habitat in a couple of ways, the first of which is by "losing cover". This means that the plants and grass that grow on the edges of streams and river banks are trampled and squashed, or eaten. This foliage acts as a protective cover for the river. Without it, there is nothing to provide shade, which causes water temperature to increase. It is also easier for silt, a fine sand-like sediment to fall into the water and choke salmon eggs. Rivers can also become polluted with silt if erosion occurs, which is the second problem caused by overgrazing. If there are enough animals, not only is the protective foliage at stake for being depleted, but the state of the river bank itself it at risk. If erosion does occur, rivers and streams become wider and may get too shallow for salmon to inhabit the area. The picture in the top left corner illustrates what a bank looks like when eroded and stripped of its vegetation.For more information click on either of the links below:
http://www.tdsfb.org/T-overgrazing.htm
http://cartt.4j.lane.edu/ttr/threat/threat.html
