XVI International Botanical Congess

Although widespread in Europe and North America, Carex flava (Large Yellow sedge), sensu stricto, is a rare species in Britain, only found at a single location, Roudsea Wood in South Cumbria. Within this site the plant is largely restricted to one area, the interface between limestone woodland and a raised mire. Concern over the survival of the plant led to the establishment of permanent quadrats to monitor the success of the population in 1967. A belt transect the width and length of the population was established (approx. 60m x 1km). Presence/absence of flowering C. flava plants in each square yard (0.912 x 0.912m) of the transect was recorded and the survey repeated every 5-7 years. The long term results show that some areas of the population have increased, while others have seriously declined. Potential reasons for these trends including management, succession and introgression are discussed along with the limitations of such surveys.