The weight of the crust: biomass of crustose lichens in tropical dry forest represents more than half of foliar biomass

In recent years, our ecological knowledge of tropical dry forests
has increased dramatically. However, the functional contributions of whole
ecosystem components, such as lichens, remain mostly unknown. In these
forests, the abundance of epiphyte crustose lichens is responsible for the
characteristic white bark on most woody plants, conspicuous during the dry
season, but the amount of resources that the lichen component represents
remains unexplored. We estimated lichen biomass in a Mexican tropical dry
forest using the bark area of trees, the dry mass of lichens per unit area
and the percentage of bark covered by lichens, together with previously
known tree densities. The lowest 2.5 m of the forests main trunks contained
188 kg/ha of lichen biomass, with lichens covering 85% of the available
bark for trees <12 cm DBH and 38% for trees >12 cm. Total epiphytic lichen
biomass was 1.34–1.99 Mg/ha. Lichen biomass represented 61% of the foliar
biomass in the forest. To our knowledge, t...