Not only does healthy riparian vegetation assist in recharging streams with water during the hot summer months, it also provides thermal cover throughout the year. The vegetation shields the lakeshores, rivers and streams from temperature extremes and contributes additional cover in the form of woody debris and undercut banks. During winter months, without the protection of the streamside vegetation, undercut banks and woody debris, some stream channels would freeze solid. Fish and aquatic insects rely on the woody materials such as logs and branches that fall into the water from the stream banks. The insects use the vegetation as a food source, and insects are food for the fish.
Fish use large woody debris, overhanging vegetation and undercut banks as hiding and thermal cover.
In the Bear River drainage in western Wyoming, improving riparian vegetation and bank stability on Huff Creek increased the cutthroat trout population from 35 trout per mile of stream to 170 trout per mile of stream in nine years. Allen Binns and Ron Remmick of the Wyoming Game and Fish Department found that the quantity of cover, amount of water in the stream the previous year and the size of pools all relate to trout abundance. Eighty percent of all vertebrate wildlife species in Wyoming depend on riparian areas during some part of their life cycle. They come for water, forage and relief from extreme temperatures. Additionally, riparian vegetation provides sheltered corridors for downstream and upstream movement to other habitats.