Mass loss of epiphytic lichen litter in a boreal forest

We measured the persistence of fallen epiphytic macrolichen litter as a part of developing a method for estimating epiphyte abundance from biomass of lichen litter. Annual mass loss in two pendulous, fruticose (alectorioid) lichens and three foliose lichens was determined with litterbags in an old Picea abies forest in north-eastern Sweden. Disturbance by animals caused high mass loss in alectorioid lichens during winter. Alectorioid lichens lost weight significantly faster than foliose species. In both Alectoria sarmentosa and Bryoria fuscescens, 17% of the original mass remained after one year (intact samples) compared to 39% in Lobaria pulmonaria, 44% in Hypogymnia physodes and 58% in Platismatia glauca. Half lives of epiphyte litter ranged from four months in Alectoria and Bryoria to 14 months in P. glauca. It is concluded that both growth form and extent of animal disturbance strongly influence the persistence of epiphyte lichen litter on the ground.