Aspects of growth dynamics of bilberry/blaeberry (Vaccinium myrtillus L.)
In Scotland, bilberry is well known as a member of the dwarf shrub community on moorlands, which provide valuable habitats for wildlife. Recently it has been envisaged that bilberry populations could play an important role in improving the dwarf shrub vegetation in degraded moorland areas. This study was therefore undertaken to investigate the above-ground growth dynamics of bilberry with emphasis on responses to grazing by sheep and seedling establishment. The leaf production of bilberry was increased by higher nitrogen availability. High nitrogen supply also led to greater activation of dormant buds. Abortion of buds was less when nitrogen was continuously supplied. The reproductive capacity of bilberry was shown to be decreased by herbage removal. In contrast flowering was increased following supply of high nitrogen in glasshouse conditions. Almost all the flowers developed into fruits in the field, but a very low production of fruits was reported from bilberry plants that were grown in the glasshouse. Results of a series of laboratory experiments on seed production, germination, seed storage and evaluation of a moorland seed bank confirmed that the scanty seedling recruitment of bilberry was due to the limited production of 'germinable' seeds in berries and risks imposed by the environment after dispersal particularly when seeds are in the litter layer and/or soil. This could suggest that limited picking of bilberry fruits would not have a detrimental effect on establishment of bilberry populations in moorlands. Therefore, areas could be identified which were suitable for public access and berry exploitation in Scotland. The berry production was estimated approximately to be about 3220-9660 tones per year in this zone.