Genetic characterization of heather (Calluna vulgaris (L.) Hull) subject to different management regimes across Great Britain

Heather plants were collected from 34 populations in Great Britain, which d iffered according to their geographical location and associated management histories. Comparisons of differential grazing regimes were made across 10 sites in the first year of study, whereas the influence of differential bur ning regimes was considered at four sites during the second year. The exten t of genetic variation, both within and between the selected heather popula tions, was examined using polymerase chain reaction (PCR)-based DNA fingerp rinting methodologies. Initially, high genetic variation within populations obscured differences between populations. Heather stands that were geograp hically close proved to be genetically similar. Site latitude and longitude were strongly associated with genetic differences between heather populati ons; however, a range of grazing and burning management treatments had no c onsistent effect upon genetic diversity. The results represent the first na tional survey of genetic variation at the DNA level within UK populations o f this important heathland species. They provided insights into the genetic structure of heather-dominated heathlands, revealing a lack of clonal domi nance within populations, but rather a much more varied genetic makeup than might have been expected given the species' ability to propagate vegetativ ely. The processes that influence genetic diversity in heather populations are discussed, and the potential role of molecular techniques in heathland conservation is considered.