Retention of Forest Strips for Bird-life Adjacent to Water and Bogs in Norway: Effect of Different Widths and Habitat Variables

Abstract

In Fennoscandinan forestry, retention of forest strips as a buffer adjacent to water and bogs has long been recommended, but their biological value is poorly known and practice varies greatly. This study explored the value for breeding birds of retaining buffer strips of different width and structure, after clear-cutting in coniferous forest. The presence of birds during their nesting season was inventoried in 370 strips in south-eastern Norway. The species number per 100 m strip length increased with increasing strip width up to about 30 m width, and then remained constant up to 70–100 m width. Generalist species dominated all width categories. Important habitat factors other than strip width were basal area of spruce, short visibility and tree height. Although 11–20 m wide strips had the highest density of species and individuals per hectare, buffer strips of about 30 m width may be recommended, as narrower strips had fewer species per unit length of edge.