Abstract
The establishment of exotic species is recognised as a particular concern in nature management, and especially species affecting plant-soil feedback dynamics as they may alter vegetation development patterns. 'Ecological effects of expanding nitrogen-fixi ng species in vulnerable ecosystems' is a project investigating which factors determine the establishment and expansion of Cytisus and Lupinus in vulnerable nitrogen-limited habitats and the ecological effects of this expansion. We use a spatial model fra mework to predict future distribution and provide knowledge of how different measures can be taken to prevent unwanted expansion and negative ecological effects of invasive species on vulnerable sand dune and heathland ecosystems and species therein. Deta ils on establishment dynamics and local expansion will be provided and the importance of the plant-soil feedback on the vegetation dynamics both before and after control measures investigated. Molecular studies of genetic structuring and diversity of Cyti sus will provide information on the origin and rate of expansion of different populations and elucidate the delicate situation where both native and exotic genotypes of the same species are expanding. The project will make us able to decide whether the re cent range expansions of Cytisus are due to increased invasiveness, increased frequency of introductions, or other processes at landscape level affecting dispersal and establishment. This approach will provide knowledge for improved management at differen t scales addressing adaptive management opportunities for a preventive landscape management of this species.
Norway