Establishment and growth characteristics of inshore populations of Ligusticum scoticum (Apiaceae)

Abstract

Two inshore and four shore localitites of Ligusticum scoticum in C Norway were studied regarding the growth and reproductive characteristics of the L. scoticum individuals, and the vegetation and ecology of the sites. L. scoticum showed a similar growth and reproductive characteristics at the inshore and the shore localities. The inshore localities were judged as relatively persistent on their basis of growth and reproductive characteristics and population size, and one of the inshore localities has with certainty maintained itself for at least 20 years. We suggest the inshore populations have established from seeds dispersed from the shore by birds. There were large differences in vegetation and ecological variables and cover between the inshore and the shore localities. At the inshore localities vegetation contained a large number of dwarf shrub and moss species which were almost entirely absent from the shore. Due to various physiological properties L. scoticum has a relatively better competitive ability and is better adapted to grow on inshore localities in the northern part of its distribution area. At the inshore localities L. scoticum occurred at two types of localitites: summits and rocky walls. The absence of inshore localitites in areas where conditions for further dispersal would appear to be ideal, indicate that specific conditions are required for successful establishment of L. scoticum at inshore localities. We suggest that the occurrence of L. scoticum at the summits depends to some extent promoted by the influence of birds, e.g. by nutrients in the excrements. However in the case of rocky walls this is an unlikely explanation, because individuals are often scattered over many hundreds of metres.