Five macrolichens of different thallus morphology from Antarctica (King George Island) were used for this ecophysiological study. The effect of thallus desiccation on primary photosynthetic processes was examined. We investigated the lichens’ responses to the relative water content (RWC) in their thalli during the transition from a wet (RWC of 100%) to a dry state (RWC of 0%). The slow Kautsky kinetics of chlorophyll fluorescence (ChlF) that was recorded during controlled dehydration (RWC decreased from 100 to 0%) and supplemented with a quenching analysis revealed a polyphasic species-specific response of variable fluorescence. The changes in ChlF at a steady state (Fs), potential and effective quantum yields of photosystem II (F_V/F_M, Φ_PSII), and nonphotochemical quenching (NPQ) reflected a desiccation-induced inhibition of the photosynthetic processes. The dehydration-dependent fall in F_V/F_M and Φ_PSII was species-specific, starting at an RWC range of 22–32%. The critical RWC for Φ_PSII was below 5%. The changes indicated the involvement of protective mechanisms in the chloroplastic apparatus of lichen photobionts at RWCs of below 20%. In both the wet and dry states, the spectral reflectance curves (SRC) (wavelength 400–800 nm) and indices (NDVI, PRI) of the studied lichen species were measured. Black Himantormia lugubris showed no difference in the SRCs between wet and dry state. Other lichens showed a higher reflectance in the dry state compared to the wet state. The lichen morphology and anatomy data, together with the ChlF and spectral reflectance data, are discussed in relation to its potential for ecophysiological studies in Antarctic lichens.

The community composition of epiphytic macrolichens from two tree species (Araucaria araucana and Nothofagus antarctica) was conducted in temperate forests in the Conguillío National Park, Chile. The composition of lichen biota is influenced by phorophyte species, bark pH, and microclimatic conditions. A total of 31 species of macrolichens were found on A. araucana and N. antarctica. Most of the species showed phorophyte preference, with nine being exclusive to A. araucana and 10 to N. antarctica. The detrended correspondence analysis (DCA) indicated the formation of three communities: one representing macrolichens growing on N. antarctica and two others growing chiefly on A. araucana, either with north or south exposure. More work is needed to study the lichen biota of the forests of the Chilean Andes, which are under multiple threats, including clearing and climate change. In order to counteract such risks to native forests and to the biodiversity of the associated epiphytic lichens, conservation plans should be established that consider the factors that influence the composition of the lichen community.

The Valdivian region has a temperate rainy climate with differences in rainfall throughout the year. This heterogeneity results in periods of summer drought that expose the poikilohydric epiphytes to desiccation. With this research, we aim to answer different research questions related to phorophyte preference, response to desiccation, and response to radiation. How does the diversity of macrolichens vary at a local and microclimate scale in three tree species within an evergreen forest? What is the tolerance limit of macrolichens against prolonged desiccation, according to evaluation of the maximum efficiency of PSII (Fv/Fm) and pigment concentration? What is the tolerance limit against a potential increase in radiation? We found that macrolichen communities are determined by tree species, which regulate the suitability of the substrate by modifying the temperature and humidity conditions. In addition, our results show a rapid photosynthetic alteration in temporal exposure to desiccation, measured through Fv/Fm and pigment concentration. Our results showed that the most sensitive lichens to radiation and desiccation are not coincident. We confirm the low tolerance of macrolichen species to high radiation, reflected in the saturation profile obtained for the set studied. The lichen community in the evergreen forest showed high complexity and vulnerability, pointing to the importance of more research.

Los líquenes son reconocidos como biondicadores de procesos ecosistémicos asociados a disturbios ambientales. Sin embargo, su evaluación en el tiempo requiere de registros sistemáticos de biodiversidad los cuales son inexistentes en la Reserva Nacional Katalalixar. El objetivo de este estudio ha sido catalogar la riqueza y distribución de la biota liquénica de la Reserva Nacional Katalalixar, no solo identificando las especies presentes, sino interpretándolas en su contexto ecológico y biogeográfico. El muestreo fue realizado al azar, en bosques de Nothofagus nitida, Pilgerodendron uviferum y en turberas. Se identificaron 70 especies, pertenecientes a 32 familias y 65 géneros. Se encontró un elevado número de endemismo, el 34% de las especies son endémicas del sur de Sudamérica, y además se suma el endemismo chileno Pseudocyphellaria guzmanii constituyendo un nuevo registro para la región de Aysén.