Experimental reintroduction of the boreal species Salix lapponum L. to refuges at the southern limit of its range — short-term results

Salix lapponum is a threatened species in locations outside its geographical range (N. Europe). In Poland, the number of populations has decreased within the last 10 years, which prompted us to reintroduce propagated plants into natural habitats. We describe our activities: from obtaining the plant material, through in vitro propagation, ex situ cultivation, to translocation and one-year monitoring. We found that plants produced in ex situ conditions are able to survive in natural habitats, but their condition depends on the production process. We noted that when the plant material was collected in May or July and the in vitro seedlings were cultivated in soil from the end of October or December and until introduction into the natural habitat at the end of May the following year, all plants survived. This contrasted the 43% of survival rate when explants were collected in September and the seedlings were cultivated in soil from February. The short-term results indicate that the morphology of plants intended for reintroduction is of great significance. This is particularly important for planning methods of plant production and acclimatization. Finally we can conclude that in the case of S. lapponum, an initial evaluation of reintroduction success is possible after just one year.