Consequences of disturbance on epiphytic lichens in boreal and near boreal forests

This paper provides a quantitative review of the consequences of disturbance on epiphytic lichens in boreal and near boreal forests, focusing on disturbance effects on lichen persistence, growth, and colonization, and on the development (recovery rates) of lichen diversity over time. Lichen persistence, growth, and colonization were examined by reviewing studies on e.g. edge-effects, lichen transplants, and logging experiments. Recovery rates were examined by reviewing studies on relationships between lichen diversity and stand age. The results from the reviewed studies were analysed by various meta-analysis methods. The review showed e.g. overall negative effects of disturbance on lichen persistence, but that persistence depend on the magnitude of the disturbance (e.g. forest edge orientation and clearcut size). However, many lichens seem to persist disturbance, and growth rates were as good in disturbed as in intact forest. The review also showed that lichen populations may need long time to recover, but that species richness does not necessarily increase over time. However, disturbance origin (logging or natural disturbance) is important to explain lichen diversity but is often confounded with stand age. The results are promising for the potential to restore and maintain lichen diversity by forest management methods based on natural disturbance regimes. Further research is needed to e.g. separate the effects of time since disturbance and disturbance type, to examine edge-effects under varying edge conditions, and to examine the influence of landscape context on stand level lichen diversity.