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Cladinaspecies are likely to suffer the impact of human pressure, resulting in a potential, as well as currently unknown, extinction risk for some of them. In this study, we used herbarium specimen data and literature data combined with geographic information system (GIS)-based analyses to assess the threatened status of ItalianCladinaspecies according to IUCN criteria. A total of 485 records, reported during the period 1833–2013, were evaluated. Biological traits, habitat requirements and distribution patterns were used to infer species extinction risk. Extent of occurrence and area of occupancy have been calculated at the national scale, based on a 2 km × 2 km cell grid. The potential threats for the taxa were assessed using a decision-support protocol in order to set conservation targets for taxa lacking population viability analyses and habitat modelling data. The species were assigned to the IUCN categories mainly using the geographical criterion B, related to species with restricted and fragmented distribution and continuous declining trend, but the species have been tested against the maximum number of criteria for which data were available and/or appropriate. This has provided an opportunity to discuss some basic aspects of the process of lichen red-listing, suggesting some methodological improvements for the mat-forming ones. [ABSTRACT FROM PUBLISHER]

Recent hypotheses suppose that dry lichens emit a faint chlorophyll a fluorescence because of a “long-wavelength quencher” embedded in the antenna complex that protects photosystem II (PSII) from photodamage. To verify in the field the PSII re-activation promptness induced by water availability, chlorophyll a fluorescence was measured on the epiphytic lichen Flavoparmelia soredians after two months without rainfall events in a Mediterranean cork oak wood (Bosco Santo Pietro, Sicily, Italy). Measurements were carried out at dawn and sunset on north- and south-exposed populations under different regimes of hydration and dark-adaptation. The results show that prolonged hydration increases the photochemical conveying of energy to PSII and decreases the non-photochemical energy dissipation that otherwise might occur in the antenna complex of the lichen photobionts. A slight decrease in PSII efficiency caused by photoinhibition was observed in thalli exposed to ambient light (up to 600 μmol photons m−2 s-1) only when kept fully hydrated. The results are discussed on the basis of our knowledge on the ecology of the species, that is a representative component of Mediterranean epiphytic lichen communities. [ABSTRACT FROM AUTHOR]

Recent hypotheses suppose that dry lichens emit a faint chlorophyll a fluorescence because of a “long-wavelength quencher” embedded in the antenna complex that protects photosystem II (PSII) from photodamage. To verify in the field the PSII re-activation promptness induced by water availability, chlorophyll a fluorescence was measured on the epiphytic lichen Flavoparmelia soredians after two months without rainfall events in a Mediterranean cork oak wood (Bosco Santo Pietro, Sicily, Italy). Measurements were carried out at dawn and sunset on north- and south-exposed populations under different regimes of hydration and dark-adaptation. The results show that prolonged hydration increases the photochemical conveying of energy to PSII and decreases the non-photochemical energy dissipation that otherwise might occur in the antenna complex of the lichen photobionts. A slight decrease in PSII efficiency caused by photoinhibition was observed in thalli exposed to ambient light (up to 600 μmol photons m−2 s–1) only when kept fully hydrated. The results are discussed on the basis of our knowledge on the ecology of the species, that is a representative component of Mediterranean epiphytic lichen communities. [ABSTRACT FROM AUTHOR]

Physicochemical deterioration processes driven by lithobiontic microcolonial fungi (MCF) and endolithic lichens (EL) are still mostly unresolved. Here, the millimetric penetration of MCF strains within silicate and carbonate lithotypes was quantified. The influence of petrographic features in determining hyphal passageways satisfies a model of physical penetration during the early stages of colonization, already described for EL. The MCF and EL secretion of iron-chelating metabolites accounts for iron mobilization in desert-varnish formation, often putatively related to fungal colonization. Increased dissolution of limestone by the model iron chelator desferrioxamine indicates the possible involvement of these MCF and EL secretes in pitting carbonates. [ABSTRACT FROM AUTHOR]

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]