Hänglavsförekomst i olika kantzoner : En studie i skogarna kring Fällfors, Skellefteå kommun

Sammanfattning: Epiphytic lichens require an even climate (no major changes in temperature and humidity) and continuity in the forest to thrive and grow, but forestry and its clear cutting destroys these habitats. The consequences are particularly serious when it occurs in forests with a high degree of management continuity. Clearcutting results in fragmentation of the forest landscape, which increases the difficulties for epiphytic lichens to find suitable habitat. In an edge zone that forms between forest fragments and clearcutting, the microclimate changes considerably, implying for example increased light, change in temperature and humidity and higher wind speed. This study examined how Alectoria, Bryoria and Usnea are affected by edge zones between forest and watercourses and clearcuts to test if these differ from forest without an edge zone. The study also examined what effect the canopy opening (light) has on the epiphytic lichen.   The result showed that there was a significant difference in the occurrence of epiphytic lichens between the different edge zones and forests without any edge zone. Canopy opening also had an impact of the epiphytic lichens, where Bryoria was generally positively affected of it. Cautious conclusions that can be drawn from this study are that Usnea can live in different types of forests and light conditions, Bryoria needs a lot of sunlight and Alectoria wants a stable microclimate without rapid changes in light, moisture and wind conditions. Previous research states that there are many factors that come into play to explain the effect a certain edge has on a certain lichen, something also established in this study