Detailed knowledge of the habitat requirements of species is required because habitat greatly affects the
persistence of species. We investigated the effects of tree species and microhabitat heterogeneity on the
population of the locally threatened lichen Lobaria pulmonaria. We studied four L. pulmonaria populations
in Central Spain and collected microhabitat data for individuals growing on beech and oak. The
microhabitat affected the life stages of L. pulmonaria; being a phorophyte species the location of the
lichen was the most important factor generating different patterns of establishment, abundance, thallus
size and reproductive capacity. Although oak forests favoured the establishment and recruitment of new
L. pulmonaria individuals, they apparently provided adverse environmental conditions for lichen growth,
thus affecting the reproductive capacity since this is size-dependent. By contrast, beech forests offered a
more favourable microclimate, because L. pulmonaria individuals reached larger sizes in these forests. In
conclusion, our results indicate that habitats hosting large populations, with high rates of establishment
and recruitment do not necessarily favour other life-cycle stages