Lascaux Cave (Montignac, France) contains paintings from the Upper Paleolithic period. Shortly after its discovery in 1940, the cave was seriously disturbed by major destructive interventions. In 1963, the cave was closed due to algal growth on the walls. In 2001, the ceiling, walls and sediments were colonized by the fungusFusarium solani. Later, black stains, probably of fungal origin, appeared on the walls. Biocide treatments, including quaternary ammonium derivatives, were extensively applied for a few years, and have been in use again since January 2008. The microbial communities in Lascaux Cave were shown to be composed of human-pathogenic bacteria and entomopathogenic fungi, the former as a result of the biocide selection. The data show that fungi play an important role in the cave, and arthropods contribute to the dispersion of conidia. A careful study on the fungal ecology is needed in order to complete the cave food web and to control the black stains threatening the Paleolithic paintings.

Despite evidence of damaging human impacts, cave paintings may again be threatened if visitors are allowed access.

The walls and ceiling of Altamira Cave, northern Spain, are coated with different coloured spots (yellow, white and grey). Electron microscopy reveale