Plant Ecology Research
Students working in my lab have examined how landscape level factors influence plant communities (Mandy Ross, Natalie Jones, Christine Petersen), the influence of exotic species on native communities (Laura May), factors affecting germination rates of native species (Montana Burgess, Annika Trimble), as well as the ecology of plant mating systems (Amy Simcox, Hazel Cameron-Inglis and Anita Purcell).
Student and Projects
Influence of emergence time on reproductive fitness in a spring ephemeral
Hazel Cameron-Inglis (B.Sc, Honours ), Amy Simcox (B.Sc, Directed Studies), Anita Purcell (B.Sc., Directed Studies)
The purpose of this field experiment was to evaluate the influence of time of flowering emergence on the seed set of an early flowering plant. Sagebrush buttercups (Ranunculus glaberrimus) has a long flowering season with flowers emerging from late February to late April. We recorded the flowering phenology of a population of sagebrush buttercups for three years. We hypothesized that early emerging flowers would rely more on self pollination while late-emerging flowers would set more seed through outcrossing. More than 200 sagebrush buttercups were subjected to one of five treatments (control, bagged with cut bag, bagged, emasculated, and emasculated and bagged) to determine whether plants that can self vs. outcross will have show the same relationship between seed set and flower emergence time for three consective field seasons. In addition, we also compared (primarily through Amy Simcox’s work) the contribution of primary and secondary flowers on reproductive fitness. Funding: TRU CUEF/UREAP
The effect of buffer strip size and type on brophyte functional group diversity and abundance in high elevation Montane Spruce forest.
Christine Petersen (M.Sc., completed July 2010)
This project was conducted in collaboration with Scott Black, (UBC-V), Gary Bradfield (UBC) and John Karakatsoulis (TRU). The primary objective of this project was to evaluate the influence of buffer strip type and width on bryophyte functional groups. Funding: FIA-FSP
Influence of Centaurea maculosa on a grassland plant community in Lac Du Bois Provincial Park
Laura May (Honours, B.Sc., completed 2009)
This project has investigated the effect of increasing abundance of knapweed (Centaurea maculosa) on native plant communities in the Lac Du Bois grasslands. First, community level data collected in the field were used to identify native species that had negative or neutral response to increasing knapweed abundance in the grasslands. Based on this field data, the effect of (±)-catechin application on root radicle length during germination trials was determeined for positively or neutrally associated species. This research demonstrated that species that are negatively correlated with high knapweed abundance in the field have lower root radicle growth with application of (±)-catechin while species that showed no relationship with the abundance of knapweed in the field also had no response to the application of (±)-catechin. Funding: TRU CUEF/UREAP
Effect of aspen stand size on understory plant diversity
Natalie Jones (B.Sc., completed 2008)
This research investigated the association between understory plant richness and aspen stand size in the aspen-grassland matrix of Lac Du Bois Provincial Park. The total richness of native and exotic species showed no significant association with patch size. In contrast, however, the richness of aspen-indicated species (as identified by Indicator Species Analysis) showed a positive association with patch size, while grassland-indicated species exhibited a significant negative association with patch size. Likewise, functional plant groups that differ in dispersal ability (dry-fruited vs. fleshy fruited species) also showed differential association with increasing patch size. Dry-fruited species exhibited no association with patch size, while fleshy-fruited species exhibited a significant positive association with patch size. Funding: TRU CUEF/UREAP
Effects of thaw slumping on germination and seed weight in Arctic grasses
Annika Trimble (B.Sc., completed 2008)
This research was completed in collaboration with Pippa Seccombe-Hett (Aurora Research Institute). The objective of this study was to investigate the effects of thaw slumping on seed production and viability in four colonizing grass species found both on and off of thaw slumps. It was expected that seeds produced within slumps will weigh more and germinate in higher proportions than off-slump seeds of the same species, due to improved growing conditions. On-slump seeds had significantly higher germination counts than off-slump seeds across all collections combined (p = 0.0155) and in several of the individual collections (Fig. 3). The difference in germination results may be due to the improved growing conditions found within the disturbances to genetic differences between populations located on- and off-slumps. Funding: Aurora Research Institute in Inuvik, NWT, and by the Polar Continental Shelf Project.
The influence of plant ecological characteristics and pre-sowing treatments on germination percentages in native grassland plant species.
Montana Burgess (B.Sc., completed 2007)
The purpose of this project was to evaluate the influence of specified ecological characteristics and pre-sowing treatments on seed germination of 13 native grassland plant species. Seeds from native species typically growing in disturbed and undisturbed habitats were subjected to four pre-sowing treatments (control, imbibition, cold stratification, and mechanical stratification. The results indicated that species which occupied disturbed habitats had significant greater mean germination percentages than the species commonly found in undisturbed habitats in three of the four pre-sowing treatments. In comparison pre-sowing treatment showed no significant difference in germination percentage. Although, some research has shown that pre-sowing treatments can influence germination percentages, other research suggests that additional factors, such as seed quality, or as this research suggests, habitat type adaptations, may be more influential.