Epiphytic Lichen in Swedens Managed Forests : A comparison of epiphytic lichen diversity in stands of Pinus contorta and Pinus sylvestris

Sammanfattning

The exotic species Pinus contorta has been actively planted in Sweden since 1970 because of morphological traits making it favoured in biomass production. Differences in traits compared to the native Pinus sylvestris have shown to cause shifts in species composition of vascular plants, terricolous lichen and epigaeic beetles in P. contorta stands. Due to the introduction of the species still being recent, its impacts on Swedens native ecosystems and biodiversity are yet to be fully understood. To expand our understanding on the topic, this study investigated the influence of P. contorta on epiphytic lichens in northern Sweden. Epiphytic lichen data was collected from 18 stands split between P. contorta and P. sylvestris in three different age classes around Vindeln in Västerbotten county. Species presence data was gathered at randomized study sites within each stand and lichen cover was estimated using a sampling grid fastened onto the trunk of the trees. Count data was then used to model the effects of stand age and host tree species on epiphytic lichen species-richness and epiphytic lichen abundance, whilst lichen cover was compared using an ANOVA. The statistical analyses revealed no significant influence of host tree or stand age on neither species richness, abundance nor cover. Although P. contorta did not significantly affect epiphytic lichen in this study, its effects on other species groups should not be disregarded and our current knowledge is still restricted to first generations of the exotic pine. How P. contorta influences native biodiversity in the long term is still unknown and will require continued monitoring.