Andre Aptroot

Diversity and ecology of lichens on churches in The Netherlands

This study presents the results of an inventory of lichen species on the walls of 344 medieval and renaissance churches in the Netherlands. In total, 194 species were recorded, of which several are more or less confined to this habitat in the country. We found several regional differences in species composition: 1. Churches in the Southwest are characterized by soft-limestone inhabiting species such as Opegrapha rupestris and Verrucaria calciseda; 2. Churches in the Rhine-Meuse-IJssel valleys are relatively species-rich and often harbour large quantities of Lecanora pannonica; and 3. Churches in the Northwest have many species that are usually found as epiphytes, like Cliostomum griffithii, Lecanora chlarotera and Lecidella elaeochroma. Multivariate analysis (PCA) shows four main ecological species groups: 1. epiphytes; 2. shaded limestone species; 3. sun-exposed limestone species; and 4. acidophilous species. The main determining factors are sun-exposition, substrate acidity and air-humidity.