How do saproxylic beetles differ in spruce (Picea abies) forests of different age? : A comparison between nature reserves and production forests, in county of Östergötland.

Abstract: Today, old growth forests are continuously decreasing, due to deforestation, threatening species to extinction. Species dependent on dead wood, different stages of decaying wood, large trees, and forest cover continuity have a particularly high risk of extinction, such as saproxylic beetle species. The aim of this study was to explore effects of forest management and some ecological factors on saproxylic beetles in spruce dominated forests, in County of Östergötland in Sweden. Sampling was done by mounting 175 window traps in 35 study sites of different age, around the county. Results showed that nature reserves had the highest number of species, individuals, and threatened species, while production forest, 15-25 years old, had the lowest. Production forests, 65-85 years old, had similarities in species composition with nature reserves, probably due to historical reasons. To some extent, these kinds of forests provide habitat for threatened species at a landscape level and could provide habitat for more threatened species in the future, with the right management. Quantity and quality of dead wood, basal area/ha, and vegetation cover increased species richness and number of individuals. Suggestions to generate a successful long-term conservation is to increase total amount of dead wood, improve diversity of dead wood, leave more large-sized trees during retention and a mixture of tree species in production forests. This will probably aid species dependent on later successional stages, increase vegetation complexity, habitat heterogeneity, and probably increase both number of individuals- and saproxylic beetle species in production forests in the future.