Recovery of the endangered false hop sedge: A ten-year study

With a growing number of species at risk of extinction, reintroductions have become an important component of several recovery schemes. In 2005, a recovery program including reintroduction and reinforcement efforts as well as monitoring activities was implemented in Québec for the endangered false hop sedge (Carex lupuliformis). Between 2005 and 2010, a total of 600 plants were reintroduced in different habitats (dry and wet) on five distinct sites (swamps). Our objective was to determine which environmental variables (soil moisture, light availability, competition, aphid infestation) influenced the survival and vigour (height, number of shoots, number of fruiting shoots) of the transplanted individuals. We also compared the survival, growth and fecundity of transplanted and wild individuals. Discriminant analyses and ANOVAs indicated that exotic aphid infestation, excessive soil moisture and low light availability were the main causes of premature transplant death. Soil moisture (when not excessive, as shown by the survival analyses), light availability and competition volume positively influenced transplant vigour. Although only 4% of original transplants remain alive after a decade, at least one new population has established and total population has increased six-fold, when wild individuals and transplants still alive in 2015 are included in the calculations. Furthermore, at least 33% of transplants produced seeds at least once. Overall, transplants were less vigorous than wild individuals, but were found to live on average just as long, suggesting that the biological success of our reintroduction program is promising. Further studies of false hop sedge should include an examination of seed viability, to evaluate whether the small, newly-created populations experienced reduced germination.