Habitat separation by sympatric forest grouse in Fennoscandia in relation to boreal forest succession

• Published in: Canadian Journal of Zoology
• Main Authors: Swenson, Jon E., Angelstam, Per
• Format: Article in Journal/Newspaper
• Language: English
• Published: Canadian Science Publishing 1993
• Subjects: Fennoscandia
• Online Access: http://dx.doi.org/10.1139/z93-180; http://www.nrcresearchpress.com/doi/pdf/10.1139/z93-180

Sympatric forest grouse in intensively managed conifer-dominated forests of the southern boreal zone in Sweden occupied different forest successional stages. Black grouse (Tetrao tetrix) selected forest stands 0 – 20 years old, hazel grouse (Bonasa bonasia) selected those 20 – 50 years old, and capercaillie (Tetrao urogallus) selected those ≥90 years old. Moreover, hazel grouse also selected stands with 1 – 10% deciduous trees, whereas capercaillie selected stands with no deciduous trees. The relative numbers of each grouse species were similar in two areas of intensively managed industrial forest, but differed in an area where forestry was less intensive and where forests had old-growth characteristics, i.e., they were old and multi-layered. Black grouse dominated in the intensively managed areas, whereas hazel grouse dominated in the less intensively managed area. We suggest that under natural conditions, black grouse inhabited the early-successional stages of forest following burns, hazel grouse inhabited the next, denser, successional stage and also old-growth spruce-dominated forests in fire refugia, and capercaillie inhabited stands of open, old, pine-dominated forest maintained by forest fire. The black grouse appears to be preadapted to the modern system of clearcut forest management. However, this system is clearly detrimental to the hazel grouse and capercaillie. To maintain all three species in a managed landscape, forest managers must strive to mimic more closely the natural variation in types and sizes of forest stands.