Distribution and habitat ecology of the threatened forest lichen Lobaria pulmonaria in Estonia

Lobaria pulmonaria is a widely used as an indicator species of undisturbed old-growth forests ecosystems, but the knowledge about its habitat ecology is still highly fragmented. To quantify the distribution, habitat preference and host tree specificity of Lobaria pulmonaria we utilised data from databases and field surveys in Estonia. The number of L. pulmonaria localities is the highest in the densely forested regions, concentrated mainly in small forest patches defined as 'ecologically highly valuable'. The species grows mostly on deciduous trees, particularly on aspen ( Populus tremula). L. pulmonaria is most common in oligo-mesotrophic boreal, eutrophic boreo-nemoral and in eutrophic paludifying forests, and prefers forests with an average age of trees more than 100 years. In addition, we found that younger stands could be suitable habitats for L. pulmonaria if the structure of the stand is comparable to mature stands. In spite of the many localities of L. pulmonaria in Estonia, the species is still threatened because (1) the rotation period of tree stands is short, (2) it is abundant in forest types which are rare or under strong economic pressure, (3) and it prefers host trees which have a restricted distribution in Estonia or are not favoured in forest management practice. Kokkuvote: Hariliku kopsusambliku (Lobaria pulmonaria), ohustatud metsasambliku levik ja kasvukohanoudlus Eestis. Harilikku kopsusamblikku (Lobaria pulmonaria) on laialdaselt kasutatud looduslike vanade metsade indikaatorliigina, kuigi teadmised tema kasvukohanoudlustest on piiratud. Et saada ulevaadet h. kopsusambliku levikust, kasvukohaeelistustest ja puuliigi spetsiifilisusest Eestis, kasutasime erinevatesse andmebaasidesse koondatud andmeid. Hariliku kopsusambliku leiukohtade arv on korgeim suurema metsasusega piirkondades, peamiselt vaikestes metsaosades, mis on defineeritud kui okoloogiliselt vaartuslikud. See liik kasvab peamiselt lehtpuudel, eriti harilikul haaval (Populus tremula), olles koige tavalisem palu-, salu- ja soostuvates metsades, ning eelistades puistuid, kus puude vanus on ule 100 aasta. Siiski voib h. kopsusamblik kasvada ka nooremates metsades, kui puistus on piisavalt suuri puid. Hoolimata h. kopsusambliku arvukatest leiukohtadest Eestis on see liik siin siiski ohustatud, kuna (1) metsade raiering on luhike, (2) ta on arvukas metsatuupides, mis on Eestis haruldased voi majandusliku surve all, (3) ning ta eelistab peremeespuid, mis on Eestis piiratud levikuga voi mille kasvu ei soodusta metsamajandus.