PARENT SESSION
Poster Session 31: Rare, Threatened, and Endangered Species
Thursday, August 11, 5:00 PM - 6:30 PM, Exhibit Hall 220 A-E, Level 2, Palais des congrès de Montréal

Conserving rare plant populations threatened by highway construction: a transplantation experiment with Carex platyphylla (Cyperaceae).

Bachand-Lavallée, Virginie^*,1, Nault, Andrée^{*,1, 2}, Drapeau, Pierre¹, ¹ Groupe de Recherche en Écologie Forestière interuniversitaire, Montréal, Québec, Canada² Biodôme de Montréal, Montréal, Québec, Canada

ABSTRACT- Highway construction has a major impact on nature such as destruction of threatened plants and their habitat. Mitigation of highway impact leads to few options when route deviation is excluded or avoidance not feasible. Translocation of populations is inevitable. To preserve threatened plant populations facing destruction, transplantation is a conservation method that has been frequently used. Still, it often fails to conserve rare plants owing to its low rate of success. Transplantation success can be improved by using a method that takes into account plant ecology and life history traits. From this perspective, a transplantation experiment was designed for the broad-leaved sedge (Carex platyphylla) taking into consideration its low competitive abilities. This sedge is rare in Quebec and some populations located in the right-of-way of highway 50 between Montreal and Ottawa were threatened. In September 2002, 192 plants were translocated in three suitable sites in a nearby protected area. Thirty-two plants left in the original site, were marked as control. At each transplanting site, two transects were established: vegetation was manually removed in one, while the other was left natural. Thirty-two plants were transplanted in each transect. Number of leaves, ramets and floral scapes were recorded to assess plant size and reproductive output of each transplant before transplantation and the following spring and fall. The effects of competition removal on survival, plant growth and reproduction were analysed using frequency analysis and a two-way ANOVA. Results after a year show that survival rate of transplant was generally high (i.e. 87,5%). However, leaching was important at one site, reducing significantly transplant survival (i.e. 42,2%). Hence, data of the lather site was discarded in the analyses. Removing competition improved plant survival and reduced vegetative reproduction. Site effect on plant growth and reproduction was significant and had a greater influence than the competition treatment. Overall, transplantation success appears to depend more on site type rather than plant competitive abilities. These results also suggest that relocated plant mortality and stress for resources might be reduced by competition removal. This project was funded by Quebec Ministry of Transportation.

Key words: Carex platyphylla, Highway construction, Plant conservation, Threatened species