Abstract Detail

Ecology

Duncan, Sophie [1], Williams, Jennifer [1].

Intraspecific life history variation in the invasive range of Cynoglossum officinale, Boraginaceae.

Intraspecific variation in plant life histories can provide insight into how biotic and abiotic factors influence reproduction and survival strategies. I examined how variation in herbivory and climate influence the size at which plants flower and the occurrence of semelparity versus iteroparity in an invasive plant, houndstongue (Cynoglossum officinale, Boraginaceae). Houndstongue is a short-lived semelparous perennial in its native range, which exhibits variation in threshold flowering size due in part to climate. In its invasive range, previous studies have documented increased rates of iteroparity and a higher threshold flowering size. I hypothesized that the recent introduction of a specialist biocontrol insect from the native range would decrease threshold flowering size, and reduce the proportion of iteroparous plants in the invasive range at sites with the weevil present. I surveyed 24 sites across the northwestern United States to quantify the frequency of semelparous (flowering once) versus iteroparous (flowering in two sequential years), and to estimate abundance of a specialist root-boring insect (Mogulones crucifer) that was introduced to Canada in 1997 and has recently expanded its range to the south. I found that the proportion of iteroparous, or double-flowering plants,varied from 0-42.3% across sites and that spring precipitation best explained this variation. Warmer, drier sites had higher rates of double-flowering. Although sites varied in the abundance of M. crucifer, I detected no influence on double-flowering. I used demographic data collected from six sites to estimate threshold flowering size. Sites with a higher attack rate by weevils had a lower threshold flowering size than those with a lower attack rate. Although I did not find a significant relationship between double-flowering and the presence of the specialist weevil, given the weevil’s recent arrival, houndstongue populations have the potential to exhibit reduced rates of iteroparity and threshold flowering size in the future.

1 -
2 - University of British Columbia, Department of Geography & Biodiversity Research Centre, 1984 West Mall Road, Vancouver, BC, V6T1Z2, Canada

Keywords:
life history
Invase plant species
introduced species
Biocontrol
Iteroparity
Semelparity
Threshold flowering size.

Presentation Type: Oral Paper
Session: ECO2, Ecology 2: Invasive Plant Species
Location: Tucson A/Starr Pass
Date: Tuesday, July 30th, 2019
Time: 11:00 AM
Number: ECO2011
Abstract ID:968
Candidate for Awards:Ecological Section Best Graduate Student Paper