Cyanolichens · Genetic diversity of cyanobacterial symbionts of lichens and of free-living populations of Nostoc in biological soil crust communities of threatened alvar grasslands

Genetic diversity of cyanobacterial symbionts of lichens and of free-living populations of Nostoc in biological soil crust communities of threatened alvar grasslands

In Northern Europe habitat loss threatens not only pristine natural habitats (e.g. old-growth forests, dune environments) but also semi-natural habitat types, including calcareous grasslands (alvars). For instance, the gradual cessation of traditional land use practices directly threatens many vascular plants, associated arthropods, and fungi and also terricolous lichens in semi-natural alvar grasslands. Contemporary nature conservation policy in Europe has identified the protection of alvars and other semi-natural grasslands to be important for halting biodiversity loss. Loss of biodiversity implies not only species and communities but also loss of genetic diversity. To design effective conservation strategies for threatened biodiversity, the basic biology of the target organisms needs to be understood. Lichens are symbiotic entities consisting of at least two components, a fungus (the mycobiont) and algae and/or cyanobacteria (the photobionts), living in intimate symbiotic association. This study targeted the very poorly known relationships of symbiont specificity of threatened terricolous crust-forming cyanolichens (e.g. Peltigera, Solorina, Leptogium and Collema) and has been the first of its kind in grassland environments (alvars, dunes). In this project the genetic diversity of both myco- and photobiont of cyanobacterial lichens (cyanolichens) were studied. tRNALeu (UAA) intron sequences for cyanobacteria (Nostoc) and Internal Transcribed Spacer (ITS) for lichen mycobiont were used as genetic markers. Cyanobiont specificity of lichen mycobionts and possible overlap in the cyanobiont spectra of different lichen genera were studied. The sampling was conducted in seminatural grassland communities, in disturbed grasslands and as well as natural undisturbed forest habitats that collectively represented a natural gradient of decreasing atmospheric humidity, increasing soil pH, and increasing anthropogenic and natural disturbance. The diversity of lichen cyanobionts were compared among different habitats to determine the effects of environmental factors and disturbance history on genotype diversity patterns.

Текст от CORDIS, на английски · Данни: CORDIS, © Европейски съюз