Species dynamics of epiphytic macrolichens in relation to time since fire and host tree species in boreal forest

Abstract

AbstractQuestions(1) How is the abundance of individual epiphytic macrolichen species affected by host tree species and stand development, where canopy succession takes place in prolonged absence of stand‐replacing disturbance? (2) Do the associations between individual epiphytic macrolichen species and host tree species change through stand development?LocationThe central boreal forest of Canada (49°23′ N–49°36′ N, 89°31′ W–89°44′ W).MethodsWe estimated the percentage cover of epiphytic macrolichens on individual trees in 51 post‐fire successional stands of varying tree species composition, ranging from 7 to 209 yr since fire. We analysed how epiphytic macrolichen species cover on individual host tree species and community composition change with time since fire and host tree species using GLM and permutational multivariate ANOVA.ResultsCover of individual epiphytic macrolichen species on the host tree species increased continuously, peaked at different time scales or gradually declined through stand development in which canopy succession took place. Some lichen species exhibited exclusive association to particular host tree species. Moreover, stand age‐related trends of the cover of some epiphytic macrolichen species differed with host species. Multivariate analysis indicated that host tree species at each stand development stage supported different epiphytic macrolichen species composition.ConclusionEpiphytic macrolichen species dynamics is strongly influenced by time since fire and host tree species identity. Host‐specific preferences and their interaction with time since fire suggest that epiphytic lichen composition on a particular host tree species is not merely a random sample of the local species pool, but rather related to their time since fire‐dependent preferences for their hosts.