| Summary: | Action plan for the conservation of Psora vallesiaca Psora vallesiaca is red-listed in Sweden and assigned to the category Critically Endangered (CR). In Sweden it is known from one locality on Öland where it grows in a small population of about 30 individuals. In the spring of 2006, four new localities were discovered on Gotland. The main distribution of Psora vallesiaca streches from the Mediterranean to the steppes of central Asia. The species usually occurs sparsely but is locally common in Italy and central Spain. The Swedish populations represent outpost populations. Other isolated populations occur in Norway, Greenland and in Northern Canada. Psora vallesiaca grows on calcareous rocks or calcareous soil and appears to grow in a stable environment with a well-developed lichen flora. It reproduces sexually through spores which are produced in fruiting bodies. These occur frequently in the species and most of the individuals in the population on Öland are fertile. The locality on Öland is situated on the Great Alvar, close to Gösslunda in Hulterstad parish. It was discovered in 1970 and the population was surveyed in 1993 and 2004. The population has remained stable or possibly increased somewhat, and is found in two subpopulations c. 50 meters apart. It is currently growing on a total of eight rocks. Efforts have been made to find the species in other parts of the Great Alvar without results. There is so far no information from the populations on Gotland. The species seems to be able to establish in other localities only with difficulty, but its habitat requirements are not fully understood and there may be further localities also in other types of habitats. To ensure the survival of the species in Sweden, the number of localities must increase substantially. The action plan is focussed on a survey of the species in Sweden to determine the status and increase the knowledge about population size and the ecology of the species. A second step is to strengthen the known populations and to assemble knowledge ...
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