A comparative study of atmospheric deposits and lichen populations in a protected alpine area in the Grenoble region (France)
The atmospheric mixture deposited on ash tree stems was studied in Les Seiglieres, an alpine station located at an altitude of 1100 m in the Belledonne Mountains and in the town of Grenoble (300,000 inhabitants, altitude 200 m). The composition of the mixture of elements was fairly similar in the two stations, although the soil particles deposited on the stems had not the same geological origin. The deposit on the Seiglieres trees had a weight per area unit twice lower and a concentration of anthropic elements in this deposit three times lower than in Grenoble. Concurrently, the lichen flora of Seiglieres was studied from 1970 to 2007, showing a high biodiversity as well as important changes occurring in its composition, with a marked increase in the nitrophilous species, possibly due to higher amounts of NOx, P, Mg and S wafted over in the atmosphere.
Keywords: atmospheric deposition, lichen population, alpine areas, tree barks, ICP-MS, SEM-EDX, biodiversity, ash trees, biomonitoring, air pollution, metals, air quality, lichens, France