Intensive local surveys can complement rapid survey techniques to provide insights into the population size and ecology of lichenised fungi

We propose that insights to population ecology of lichenised fungi can be efficiently obtained by combining rapid biodiversity surveys, which representatively sample large areas, with intensive studies in selected populations discovered. To illustrate this approach, we compared results from an Estonian rapid survey scheme with an intensive local population survey of the poorly known epiphytic crustose lichen, Lecanora thysanophora. In contrast to what the data from rapid surveys suggested, the intensive survey revealed that this typically sterile species can occur in remarkably dense populations obviously limited by host tree availability; we also recorded emerging sexual reproduction in the population centre. Our results imply that the detection of even poorly identifiable species may mostly depend on total field effort.