Jonsson, personal observation). Based on literature and field expert knowledge we a priori classified lichens sensitive to light (and associated climatic conditions like drought) and lichens promoted by open habitats, and both groups increased in number with time. This may seem contradictory but for some species

it may be explained by a delayed response, i.e. a time-lag between an environmental change and extinction. Gamma-secretase inhibitor Some species sensitive to light, e.g. Mycobilimbia carneoalbida and M. epixanthoides still survived on the north side of the stem in young forests, although often in a worse state and in smaller populations (F. Jonsson, personal observation, see also Hedenås and Hedström 2007). The increase could be due to an overestimation of the sensitivity of some lichens to the disturbance caused by logging operations. Old, large solitary aspens have been almost non-existing in young production forests regenerating after clear-cutting, introduced in the 1950s. The recent applications of retention approaches have restored this website trees in such an environment, and consequently it is a habitat with associated species communities, including

light- and drought-sensitive species, unknown to most lichenologists. The total number of cyanolichens did not differ between the two age classes. Leptogium teretiusculum was much more common in the young forest and Arctomia delicatula, Collema occultatum var. populinum, Leptochidium albociliatum, L. subtile, Peltigera didactyla and Peltigera membranacea

were only found in this age class. Collema nigrescens and Parmeliella triptophylla on the other hand were more common on the clearcuts. There are different opinions regarding cyanolichens Cell press and their ability to cope with disturbances. According to Hedenås and Hedström (2007) and also Coxson and Stevenson (2005) cyanolichens should be more tolerant to changes in microclimate following a disturbance such as logging, while Richardson and Cameron (2004) found that cyanolichens were sensitive to disturbance. In one study two crustose green-algae lichens were less common on retained trees than on trees in old forest, while three cyanolichens showed an opposite pattern ( Hedenås and Hedström, 2007). The most important conclusion from our results regarding cyanolichens is that they can cope with logging disturbance quite well, at least for 10–16 years. This could have several possible explanations: (1) clear-felling does not affect the cyanolichen community; epiphytic cyanolichens are quite disturbance-resistant and only need their host tree (2) there might be a time-lag in their response or (3) truly disturbance-sensitive cyanolichens have gone extinct already from the old forest or prior to the inventory. Spore-dispersed lichens were more numerous in the young forest, as we expected.