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Epiphytic lichens play a key hydrological role in ecosystems by intercepting and retaining water. These attributes can be characterized at an individual thallus scale by considering the retention and loss rates of water, themselves influenced by growth form and anatomy. We compared the hydrological attributes (water-holding capacity and standard drying rate) of two common northern temperate-boreal lichen genera, Evernia and Usnea, which differ greatly in internal anatomy. Despite conspicuous morphological and anatomical differences between the taxa that were hypothesized to affect thallus-water dynamics, their hydrological traits were found to be remarkably similar. This suggests either limited influence of internal anatomy on these ecologically relevant traits or convergence in hydrological attributes in co-occurring taxa. [ABSTRACT FROM AUTHOR]

Harvesting of fog water by epiphytes is biomechanically analogous to filter-feeding by aquatic invertebrates. Increased branchiness, as measured by fractal dimensionality, should reflect greater fog-harvesting ability. We documented changes in epiphytic macrolichens across an altitudinal gradient in fog availability in a coastal shrubland in northern Chile. Fruticose and foliose genera appear to become more abundant with increased fog availability. Fractal dimension of fruticose and foliose lichens increased significantly with inferred fog availability. The adaptive morphology of lichens is under-studied, and insights from theoretical morphology of other organisms yield fruitful hypotheses for further studies. [ABSTRACT FROM AUTHOR]

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The Italian distribution of the rare boreal-circumpolar macrolichen Usnea longissima is revised on the basis of a critical re-evaluation of bibliographic and field data. Reported from all Alpine regions of Italy, the species presently survives only in two neighbouring Alpine valleys of Friuli and Veneto. The Friulian population consists of a few thalli on a single tree near the lake of Sauris, while in Veneto scattered populations were observed in nine stands of Val Visdende with ca. 200 colonised trees. The species seems to be locally extinct in Trentino-Alto Adige. Earlier records from Lombardy, Piedmont and Aosta Valley are wrong or at least questionable. Usnea longissima can be considered as critically endangered at the national level. Some recommendations for forest managers are proposed. [ABSTRACT FROM AUTHOR]