Initiating recovery strategies for the Gulf of Saint Lawrence Aster (Symphyotrichum laurentianum) on Prince Edward Island and assessment of its reproductive abilities

The Gulf of St. Lawrence Aster (Symphyotrichum laurentianum ) (SLA) is an annual plant species endemic to the Gulf of St. Lawrence region. Due to the dynamic nature of the environment that the Gulf of St. Lawrence Aster inhabits, severe and major threats to both the Aster and its habitat exist. The Committee on the Status of Endangered Wildlife in Canada listed the species as Threatened in Canada in 2004. This status was reached due to the species' limited distribution, fluctuating population size, and to continued pressures on its habitat. Surveys have revealed that both site and population numbers have been further and drastically reduced on Prince Edward Island. In 2007 only one populated site remained with a low number of 482 individuals. It is possible that this species is on the brink of extirpation from PEI.

Recovery of this species on Prince Edward Island is feasible. Promising results related to the transplantation of greenhouse grown seedlings at four in-situ sites demonstrated that SLA plantlets have the potential to serve as seed stock to re-establish populations. Over the two years of the transplantation experiment, the pooled overall survivorship was 52.8%. Specific site manipulations that were tested may also increase the potential survivorship of the transplants, and facilitate second-generation germination. Additionally, surveys and site assessments were conducted at 15 locations within the Prince Edward Island National Park. Although the search for new SLA populations was not successful, locations were identified in both historical and non-historical areas that yielded potential sites for future management actions to recover the species on Prince Edward Island. As well; analysis of the reproductive potential of SLA florets has revealed additional knowledge useful for future studies. Pollen exclusion experiments resulted in a significant difference in the median values of excluded versus unexcluded inflorescences. These results indicate that, as far as the production of viable seeds is concerned, SLA plants benefit more from geitonogamy and crosspollination than they do from selfing (cleistogamy).