Spatial variation of eco-physiological parameters in the lichen Pseudevernia furfuracea transplanted in an area surrounding a cement plant (S Italy)

Thalli of the lichen Pseudevernia furfuracea were transplanted for 3 months (November 2010–January 2011) at 61 monitoring sites around a cement plant near Castrovillari (Calabria, southern Italy). NH₃, NO ₓ and SO₂ concentrations were monitored monthly in a subarea of 10 sites (SA₁₀) where the cement plant was located. At the end of the exposure period, the integrity of cell membranes; membrane lipid peroxidation (thiobarbituric acid reactive substances, TBARS level); vitality (cell respiration); chlorophyll a; chlorophyll b; carotenoids; phaeophytization quotient; photosynthetic efficiency and thalli concentrations of Al, Ca, Mg, V and Fe were measured. NO ₓ concentrations correlated with the site distance from the cement plant while NH₃ concentrations correlated with lichen vitality within SA₁₀. For the monitoring area as a whole, only Fe and Mg concentrations correlated with membrane lipid peroxidation, while TBARS levels showed a significant increase and chlorophyll a, chlorophyll b and carotenoids a significant decrease with respect to the lichen origin area. Multivariate analysis (detrended correspondence analysis, cluster analysis and multi-response permutation procedure) of the eco-physiological parameters × monitoring sites data set resulted in four clusters termed C1, C2, C3 and C4. The eco-physiological parameters were compared among the four clusters and lichen origin area by one-way ANOVA. An index of environmental favourableness (IEF) to lichens was calculated to evaluate the spatial recovery of impaired values of TBARS, chlorophyll a, chlorophyll b, xanthophylls + carotenoids and phaeophytization quotient. The results indicate that there is no clear spatial trend in mycobiont impairment even though the IEF values suggest a higher number of sites with low levels of membrane lipid peroxidation in the 2-–3-km distance band from the cement plant (the outermost) than in the two other distance bands (0–1 and 1–2 km). The photobiont seems to be damaged mainly in the inner distance band of the study area as suggested by the gradual but significant recovery trend of pigment levels and phaeophytization quotient from the inner distance band to the outer one (as shown by the IEF values). Conversion of chlorophyll to phaeophytin probably is not the only process affecting pigment levels.