Effekt av biotopvård på öringpopulationen i två vattendrag

I have done a follow up study of the restoration of two rivers, Röälven and Grundan, in order to evaluate the effects of the restoration on the endemic population of trout. Both rivers have been used for timber floating during many years throughout the 20th century, and because of this, had all obstacles such as rocks and wood parts removed. In 2004-2005 both rivers were restored, and rocks and wood were put back into the rivers. Spawning grounds were created and boulder dams were constructed to promote the streaming water. The result showed that the trout population of both rivers increased after the restoration, but also that the trout population of Röälven increased more than that of Grundan. My conclusion is that the way the restoration is of a river contributes to the result