Recovery of heather (Calluna vulgaris) flowering in northern Finland

Abstract

Abstract Heather is a slow-growing evergreen shrub, commonly found in moorlands and heaths of high nature conservation value. Heather-dominated areas are used as livestock pasture, and the flowers of heather are harvested also for the natural product industry. Classical studies have focused on the recovery of shoot biomass of heather, while the recovery of flowering after grazing or harvesting has received less attention. In this study, we examined the recovery of heather flowering in one harvesting experiment and two observational areas in northern Finland. The flowers of heather were collected manually by clipping the flowering shoots or stripping the flowers from the shoots or by machine harvesting. We counted the number of short shoots (SS), nonflowering long shoots (NFLS), and flowering long shoots (FLS) after harvesting. We also measured the length of FLS and counted the flowers they produced. Heathers started to recover by producing new short shoots, while the recovery of flowering was slow, and only in one out of the three areas, flowering recovered totally during our study. Our results suggest that the recovery was dependent on the age of heather or individual site characteristics rather than on the harvesting method. Because flowering is one of the most important stages of successful reproduction, which affects the long-term existence of heather-dominated ecosystems, the results of our study can contribute to new guidelines for management practices in heathlands. However, longer-term experiments on the rate of flowering recovery are needed especially if rotational cutting is favored as a management practice in heathlands in the future.