Atmospheric deposition and physiological response of the lichen Ramalina fastigiata to the urban environment of Kaunas, Lithuania

Abstract

Urban air pollution continues to be a significant problem in most parts of the world. Lichens have been shown to be good bioindicators in air pollution studies because of their dependence on the atmospheric deposition for the nutrition. The present study was focused on the effect of urbanization on the composition and atmospheric deposition inputs and damage to physiological parameters of transplanted epiphytic lichen Ramalina fastigiata. Fluxes of the total nitrogen were 0.48–1.66 kg N ha-1. The highest deposition of ammonium nitrogen was farther from the city centre, nitrate nitrogen – in the centre of the city. Annual total N and S fluxes were 4 and 3.5 times higher than background conditions (13.17 kg N ha-1 and 4.47 kg S ha-1). The results showed that thalli from the urban sites exhibited stress – the increase in oxidative stress and electrolyte leakage indicated injured cell membranes. The highest levels of deposition coincided with evidence of damage to lichen thalli.