Epsilon Archive for Student Projects

Abstract

In today’s forest landscape in Sweden, a large percentage of the forests are traditionally managed. It is clear that clear-cutting is affecting bird diversity negatively, but while many studies have been made on that connection, not so many have studied the effects of pre-clearing on species diversity of birds. In this study, I examined how pre-clearing in forest management may impact forest birds in the Swedish forestry landscape. With data of bird inventories from Swedish Bird Survey (SBS), along with management information of pre-clearing, thinning and clear-cutting from Mellanskog, a spatial and temporal investigation in QGIS was performed to identify suitable study locations. Different ecological groups of birds were selected based on their breeding needs that were predicted to respond to forest pre-clearings. Included bird species groups were shrub nesters, ground nesters and cavity nesters as control. Additionally, nesting generalists and specialists were also compared. The study was performed using a Before-After-Control-Impact design, where pre-clearing locations with a matching line transect from SBS were compared with another line transect from the same SBS route as control for Before and After studies. Some trends indicated that shrub nesters were affected negatively by pre-clearing and ground nesters positively, and one site showed significant results. But for the rest of the sites, there were no clear evidence that pre-clearing affect forest bird species composition or abundances. The lack of pre-clearing effect could be due to that this management does not have a strong enough impact to cause species to decline. The lack of detected pre-clearing effect could also be due to the limitations of the study, such as the study design and the relatively small sample size. Since Swedish forestry affect such a big part of Sweden’s forests, it is important with further research on the subject to be able to detect trends so that a sustainable forestry can meet the needs of forest birds.