Cover of Ramalina species as an indicator of habitat quality in threatened coastal woodlands

Abstract

Coastal forests in the Mediterranean area are threatened habitats due to intense human influence. In the context of global change, a rapid tool is needed for the evaluation of habitat quality in woodlands by calculating lichen cover on twigs rather than weight biomass. We selected epiphytic Ramalina species as indicators of habitat quality and evaluated them in threatened woodlands dominated by Olea europea var. sylvestris on the island of Menorca, a UNESCO Biosphere Reserve in the Mediterranean area. We measured species richness, percentage cover and dry weight in nine sites grouped into urban, rural and naturalized areas to evaluate the effect of land uses, and regressed dry weight against percentage cover. Percentage cover, dry weight, species richness of Ramalina and of its species varied depending on land use, reaching higher rates in naturalized and rural areas rather than in urban areas. In addition, we showed for the first time that field estimates of Ramalina cover at the field were related to dry weight by applying a logarithmic transformation to dry weight. Percentage cover of Ramalina was a good indicator of land uses and will be a rapid, easy and non-destructive tool to assess the quality of woodland habitats in the coastal zone.