Ecophysiological and floristic study of the lichen communities in Livingston Island

Scientific objectives:-Floristic study of Livingston Island.-Structure, succession and dynamism of the principal lichen and bryolichen communities.-Chorological study (distribution) in the Juan Carlos I base area of plantspecies with special bioclimatic significance.-Research on the early development of lichen symbiosis in relation tomicroclimate and different rock types.-Colonization and adaptation strategies of lichens in the Antarctic environment.Activities carried out:The Byers Peninsula was explored. In this extensive ice-free region, a largenumber of samples were collected on acid to ultrabasic rocks, both eruptive andsedimentary. The following places were visited:1) Beach and front moraine of Roch Dome;2) Clark Nunatak and coastal cliffs up to Elephant Point;3) NE end in the north coast of the peninsula;4) Interior uplands and Chester Cone;5) Cerro Negro and surrounding area;6) SW coast, including exploration of sedimentary rocks.Approximately 300 samples of lichens and mosses were collected, with specialattention to nitrophilous and ornithocoprophilous flora and the floraassociated with gelifraction phenomena. A cartographic survey of Umbilicaria antarctica, Usnea antarctica and Parmelia saxatilis was carried out on thesouth coast in order to check the possible E-W xericity gradient.The ice-freeregion of Hurd Peninsula and north of False Bay were explored, and an abundance of Ramalina terebrata was noted, a species unknown in the area around the Juan Carlos I base. Macrolichens unknown to occur in Antarctica were discovered andcollected near the summit of Monte Reina Sofia. The lichens could be Umbilicaria krascheninikovi, a relatively common lichen in the Andes.A detailedstudy was made of the communities associated with an extreme supply ofnutrients, particularly the so-called ornithocoprophilous communities typicalof places frequently visited by birds. It was noted that Caloplaca regalis, soabundant in other parts of the South Shetland Islands, was almost totallyabsent from these communities. With regards to the structural and dynamics aspect, the model chosen was the bryolichen communities, where competition forspace is strongest, with various strategies and forms of growth sharing a smallarea, including the epiphytic and parasitic. Small plots were described and photographed with their evolution to be measured and marked in subsequent years.In collaboration with the team of geomorphologists, an initial approach was made to the dating of recent moraines and beaches on the basis of the study ofthe succession of lichen communities. The site chosen for this study was theglacier front on the western slope of the Monte Reina Sofia and the area of beach terraces at the Juan Carlos I base. A distribution map was produced at 1:5000 scale of the species of phanerogams Colobanthus quitensis and Deschampsia antarctica, and of the lichens Sphaerophorus globosus, Placopsis contortuplicata, Himantormia lugubris, Umbilicaria aprima, U. decussata, U.nylanderina and U. antarctica. The bioindicator value taken for each of these species is as follows:1)Termophytic specie: C. quitensis, D. antarctica, Sph. Globosus;2)Cryophytic species: Pl. contortuplicata, H. Lugubris;3)Aerohygrophytic species: U. aprima, U.decussata, U. nylanderiana;4)Substratohygrophitic species: U. antarctica.The initial development of the lichen symbiosis was commenced in natural condition, and consisted in the cultivation of lichen samples in naturalstations. Five different species of lichen were selected, 4 of them with awell-characterized ecological behaviour:-Usnea aurantico-atra (spores);-Usnea antarctica (soredia);-Parmelia saxatilis (isidia);-Umbilicaria decussata (thallospores);-Himantormia lugubris (spores).The experiment will run 5 years and samples will be taken every year.Samples were collected for analysis at the University of Kiel. Twenty specimens were collected of the following species: Pseudephebe pubescens,Parmalia saxatilis, Ramalina terebrata, Placopsis contortuplicata, Umbilicaria decussata, Coloplaca sublobulata, Haematomma erythromm, Lecidea sciatrapha,Usnea antarctica, Usnea aurantico-atra, Umbilicaria antarctica.