Vitality of lichens under different light climates in an Araucaria forest (Pró-Mata RS, South Brazil) as determined by chlorophyll fluorescence

Abstract

Th e vitality of 64 lichen species (107 individual lichen thalli) growing under diff erent light climates in an Araucaria forest in South Brazil was analyzed by chlorophyll fl uorescence. Study sites were grouped according to their local light availability under full sunlight (about 2200 µmol m -2 s -1 ): 1 = low light, up to 20 µmol m -2 s -1 ; 2 = medium light, 20 to 100 µmol m -2 s -1 ; and 3 = high light, more than 100 µmol m -2 s -1 . Maximum quantum yield of photosystem II, as shown by F v /F m of dark-adapted samples, was mainly between 0.3 and 0.7, with extremes of below 0.1 and up to 0.85. On average, yields were highest with low light availability (0.66). Groups 1 and 2 were not signifi cantly diff erent from each other, but groups 1 and 3, as well as groups 2 and 3 were. After dark adaptation, lichens were exposed to diff erent light intensities by means of a chlorophyll fl uorometer. Th e results show that low light-adapted lichens exhibit the highest sensitivity to excess light, as was also indicated by the data for non-photochemical quenching. Th us, shade-adapted lichens are obviously well protected from possible damage caused by excess light, which is important when exposed to sun fl ecks.

Abiotic effects on the cover and richness of corticolous lichens on Araucaria angustifolia trunks

“…However, there are few studies on these factors in Brazilian ecosystems (Martins et al 2011;Käffer & Martins 2014), especially considering different habitats in Mixed Ombrophilous Forest (araucaria forest), for which there is scarce knowledge on lichen ecology (e.g. Fleig & Grüninger 2008;Käffer et al 2009;Koch et al 2012;Hampp et al 2018).…”