Dimensional and age structure of populations of epiphytic lichen Hypogymnia physodes (L.) Nyl. under conditions of atmospheric pollution

Atmospheric pollution (SO2 and heavy metals) causes consistent changes in t he dimensional and age structure of local Hypogymnia physodes populations g rowing on fir trunks. The age states were distinguished according to the qu ality of soralia and the degree of their development. Upon an increase in p ollution, the frequency distributions of thallus weight and length shift to ward smaller individuals, although their type remains relatively stable (ex ponential for weight, lognormal for length). Upon transition from the backg round to the impact zone, the spectrum of age states shifts from highly fer tile to minimally fertile and sterile individuals.