Browsing by Subject "Europe"

Lichens are symbioses between fungi, photosynthetic algae and other organisms. The fact that several different fungi may occur in the same lichen thallus adds a further dimension to the diversity of these miniature ecosystems. Calicioids are a polyphyletic group of predominantly lichenised fungi which includes many species with stalked ascomata, topped with a persistent spore mass (mazaedium). One such species is Chaenotheca chrysocephala, a relatively common crustose lichen with a wide distribution. The lichenicolous fungus Chaenothecopsis consociata grows on the thallus of C. chrysocephala and is generally considered to be a parasite. This study aims to map the temporal and geographical distribution of C. chrysocephala and C. consociata in Europe in order to find out whether the parasite was present there before the year 1942, when the species was described, and to identify possible patterns which may affect the population dynamics of these two species. This study found that C. consociata was indeed present in Europe before 1942, at least in Norway, Sweden and Finland. Additionally, the percentage of infected C. chrysocephala thalli seems to have increased in Europe since the parasite was first found. The GBIF dataset showed a significant increase in infected C. chrysocephala thalli in northern Europe (N-EU) compared to central-southern Europe (CS-EU). Although the exact reason is unclear, this increase may be related to differences in forest structure across Europe. Firstly, the host lichen seems to prefer Picea and Pinus as its substrate, these being typical trees of needleleaf forests in Europe. Furthermore, the decrease of old-growth forest stands in Sweden and Finland may have reduced suitable habitat for the host, while the concurrent increase of disturbed stands may have favoured the dispersal of the parasite.