How can we protect rare hemiparasitic plants? Early-flowering taxa of Euphrasia and Rhinanthus on the Baltic island of Gotland
2005 (English)In: Folia Geobotanica, ISSN 1211-9520, Vol. 40, no 2-3, 261-272 p.Article in journal (Refereed) Published
Euphrasia stricta var.suecica, E. stricta var.tenuis, andRhinanthus serotinus subsp.vernalis are three endangered, hemiparasitic annual herbs found in traditionally managed hay meadows on Gotland, Sweden. We have studied — experimentally and in the field — how some features in the present and traditional management cycle affect their fitness.
We set up permanent 50 × 50-cm plots in a coastal hay meadow where bothE. stricta var.suecica andRhinanthus are still quite common. The survival, growth and fecundity of cohorts ofEuphrasia andRhinanthus were followed throughout the growing season for three years. The length of the growing season was vital forEuphrasia andRhinanthus performance. In cooler summers, the percentage ofEuphrasia individuals that produced mature seeds was decreased by 20% at the time of mowing. This indicates the need to individually adjust the time of mowing, as was formerly done, to the actual phenological development in order to maintain healthy populations. It is also important to consider the effect of time of mowing on total species richness, asEuphrasia more successfully established in 10 × 10-cm squares with high species richness. Also, the time in spring when hemiparasite growth started was crucial. Cohorts of bothEuphrasia stricta var.suecica andRhinanthus that connected to hosts and started growing early in the season had a strong advantage over later cohorts by having fitness values four to eight times higher. From this we conclude that the traditional practice of spring raking is important for the long-term persistence of these hemiparasites, since raking promotes an earlier onset of both host and hemiparasite growth. Another important issue is the traditional, but nowadays often neglected practice of letting the hay dry in the meadow after mowing. Hay that was left to dry in the meadow contributed significantly moreRhinanthus seed to the meadow than hay that was taken away immediately after mowing. We also found that seedling emergence and subsequent growth ofEuphrasia stricta var.suecica was greatly enhanced by a second hay cut in September. A second cutting mimics some of the positive effects of the traditional practice of aftermath grazing, which is nowadays often abandoned.
Place, publisher, year, edition, pages
2005. Vol. 40, no 2-3, 261-272 p.
IdentifiersURN: urn:nbn:se:uu:diva-76571DOI: 10.1007/BF02803239OAI: oai:DiVA.org:uu-76571DiVA: diva2:104483