Site factors determining epiphytic lichen distribution in a dieback-affected spruce-fir forest on Whiteface Mountain, New York: stemflow chemistry

Epiphytic lichen diversity in a dieback-affected forest of red spruce (Picea rubens Sarg.) and balsam fir (Abies balsamea (L.) Mill.) on Whiteface Mountain, New York, U.S.A., was higher on dead compared with living trees and on fir compared with spruce. Diversity differed more between living and dead spruce than between living and dead fir. Cover of all lichen species that occurred on more than 50% of the sample trees, except for two species, decreased with increasing mean concentration of NO3– in stemflow. Concentrations of NO3– were higher on living spruce compared with dead spruce and with living and dead fir. The negative correlations between lichen cover and NO3– concentration may reflect either a decrease of lichen abundance caused by toxic effects of higher NO3– concentrations or a removal of NO3– from stemflow by epiphytic lichens. Experimental exposure of Hypogymnia physodes to NaNO3 reduced chlorophyll concentrations. This result, together with estimations of lichen and needle biomass, indicates that a dependence of lichen cover on NO3– concentrations in stemflow may be the cause for the negative correlations. The sulphur concentration in stemflow did not affect lichen abundance on Whiteface Mountain. The manganese concentration in stemflow may have an effect on single species

Lichenological studies in the western sectors of the Alps : Sesia Valley (Piedmont, Italy)

Ce travail a eu pour objectif l\u27étude de la diversité des lichens dans les régions montagneuses des Alpes. 191 taxa sont présents dans la Valle Sesia (Piémont, Italie); 20 sont nouveaux pour le Piémont, 53 sont nouveaux pour le secteur étudié, enfin 3 sont la deuxième citation pour l\u27Italie. Un catalogue, avec des remarques relatives à l\u27écologie et à la distribution, est présenté.The purpose of the survey was to study lichen diversity in uplands areas of the Alps. 191 lichen species are reported from the Sesia Valley (Piedmont, Italy). 20 of these are new to Piedmont, 53 are new to the investigated area and 3 are the second report for Italy. An annotated list, with ecological and distributional remarks, is given.</p

Lichen colonization on stoneworks: examples from Piedmont and Aosta Valley

Data on lichen presence on some monuments from Piedmont and Aosta Valley are reported. Sampling techniques, chosen on the basis of lithological characteristics of the substrata are described, and the ecological significance of the identified species is discussed. Preliminary data indicate that the majority of the species are neutro-basiphytic and rather nitrophytic, xerophytic and photophytic. Finally, most species appear to belong to the Caloplacion decipientis alliance