Significance of forest structure and landscape elements on forest bird richness in Denmark

Abstract

Several studies have demonstrated the importance of forest structure on forest bird species richness. The objective of the present study was to determine the importance of forest structure on forest bird richness in Denmark. For this purpose three components of the forests were taken into account; tree height, type (coniferous or deciduous) and canopy cover. These three data sets were linked to data from a bird census carried out by volunteers throughout Denmark and different statistical analyses were performed. The results of the statistical analyses highlighted the importance of canopy cover when considered within a 500 meters buffer zone. The statistical analyses also showed that the percentage of forest is a significant factor explaining the richness of forest birds. If a certain threshold of percentage of forest is reached, then trees measuring over 17 meters are also considered as factors positively influencing forest bird richness. At the species level, whether the forests are dominated by conifers or deciduous trees does not affect richness, the key factor being the proportion of forest. However, it is clear that other factors that were not taken into account in the analyses conducted in this thesis are likely to influence forest bird richness in Denmark. Another limitation of this study is that the data used in the analyses are from different years and sources.