Epsilon Archive for Student Projects

Abstract

The use of indicator species is wide spread and an important tool in nature conservation for the identification of valuable biotopes and prioritizing conservation efforts. This study aimed to test if it can be a problem to use indicator species that builds on expertise rather than documented studies. I tested this for Microbregma emarginatum (Coleoptera; Ptinidae), an indicator for coniferous forests with high conservation values. My questions were 1. Is the species more abundant in protected forests compared to commercial forests? 2. Does the species prefer older trees? 3. Does the species prefer sunlit trees? To answer these questions I did field inventories in two counties of central Sweden, where the presence of the species exit holes on Norway spruce (Picea abies) were examined. A total of 12 locations were chosen, six of them were in protected areas; nature reserves or National parks, the other six were in commercial forests. On each location, 30 trees of Norway spruce were examined along line transects. On each tree the diameter was measured to get a reference for the tree age. Sun exposure was estimated and a value representing the vegetation density was given each location. The results showed that Microbregma emarginatum is more abundant in protected areas where the proportion of trees with presence of the species was 51% higher compared to commercial forests. The species do seem to prefer older trees since every spruce with a diameter of 62.4 cm or more showed its presence. Also sunlit trees seems preferable because the location with the highest value for sun exposure also had the highest proportion of trees with presence of the species. This concludes that the species is a suitable indicator for higher conservation values despite the fact that it was found in some commercial forest as well, since these parts of the forests had more of a continuity.