Visualisation of the influence of habitat on lichen occurrence, Toruń, Poland

The main aim of the paper was a visual comparison of lichen distribution with urban environmental factors. This paper presents a cartographic method for representing the spatial distribution of anthropogenic and natural factors in atmospheric air pollution and prevalent elements of the natural environment and their correlation to occurrences of two selected lichen species – the acidophilous Hypogymnia physodes and the nitrophilous Xanthoria parietina in the area of Toruń (Central Poland). Lichens are a good indicator of changes in habitat conditions. Analyses of the occurrence of lichens in Toruń were conducted for data covering a period of more than 60 years. A choropleth map method (a square tile grid map) was used, based on a grid of 144 one-kilometre squares (ATPOL). An inventory of taxa was made in 137 squares (localities). This recorded the type of substrate and abundance (extent) of occurrence