Abstract Detail


Mulholland, Samantha [1], Costea, Mihai [2], Stevens, Kevin [1].

Examination of interactions between Sida hermaphrodita and Phragmites australis: Seedling growth and mycorrhizal colonization.

Virginia Mallow (Sida hermaphrodita) is a perennial herb of the Malvaceae family that is native to riparian habitats in northeastern North America. Throughout most of its distribution, however, it is considered threatened and only two populations are known from Canada. Canadian federal assessments of the conservation status have outlined several threats including loss of habitat due to invasive species including Common reed (Phragmites australis). The biology and ecology of S. hermaphrodita are still poorly understood and few studies have been performed to determine the factors that contribute to the species rarity. We conducted studies to quantify interactions between S. hermaphrodita and P. australis in both greenhouse and field conditions. In 2016/17 a series of vegetation surveys were conducted to assess the capacity of P. australis to affect the establishment of S. hermaphrodita seedlings and test the hypothesis that S. hermaphrodita seedlings will be negatively impacted by soil modifications effected by P. australis. This study took place at one of the two known locations where S. hermaphrodita has been documented (Taquanyah Conservation Area, Ontario Canada).  Twenty-eight 1 x 1 m plots were established at the periphery of S. hermaphrodita stands in areas proximal and distal to large stands of P. australis. Results from the field vegetation surveys suggested that proximity to P. australis has no significant effect on the emergence or mortality of S. hermaphrodita seedlings. S. hermaphrodita seedlings were colonized by arbuscular mycorrhizal fungi at all sites with hyphal, arbuscular and vesicular colonization levels exceeding 65, 31 and 5% respectively. There were no significant reductions in colonization associated with proximity to P. australis stands.  A greenhouse study was conducted to quantify seedling growth and mycorrhizal colonization of both species in soils that correspond to a gradient of vegetation ranging from pure stands of P. australis to pure stands of S. hermaphrodita. This study tested the hypotheses that S. hermaphrodita will perform poorly in soils proximal to established stands of P. australis whereas P. australis will perform best in soils from near its own stands. Initial results failed to support either hypothesis.  Additionally, results obtained from the greenhouse study indicated that the seedlings of both species perform best in the soils obtained from pure stands of their competitor.

1 - Wilfrid Laurier University, Biology, 75 University Avenue West, Waterloo, ON, N2L3C5, Canada
2 - Wilfrid Laurier University, 75 University Avenue West, Waterloo, Ontario, ON, N2L3C5, Canada

Sida hermaphrodita
Phragmites australis
Species Interaction.

Presentation Type: Poster
Number: PEC018
Abstract ID:655
Candidate for Awards:Ian and Syvia Taylor Award

Copyright © 2000-2018, Botanical Society of America. All rights reserved