I know that some fungi prefer mildly alkaline environments and dislike acidic environments. Is that true of all fungi, or do some fungi prefer acidic environments? If so, are such acidic fungi rare exceptions or is it common for there to be acid-loving fungi?
Fungi that grow in acidic media are well known, here just one reference: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC518635/pdf/jbacter00651-0183.pdf
About their spread, they are less common in mild environments (like you hands, or your garden soil) but of course in acidic environments, they will be predominant.