Cameron Carlyle
Contact Information:

Thesis summary

Grasslands are threatened by urbanization, agricultural conversion, over-grazing, tree-encroachment, and invasive plants. Simultaneously, climate change acts on all levels of biological organization, from entire communities to the physiology of individuals. The environmental stresses induced by climate change have the potential to interact with human-caused disturbance, but the response of plants to these stresses and disturbances, and how they may interact, are not well known. To conserve grasslands it is critical to know which types of grassland and which plant species will be most affected. To understand the mechanisms of change at the ecosystem level it is necessary to study the response at lower levels of biological organization. Using a variety of approaches I studied the potentially interacting effects of stress (primarily reduced water availability) and disturbance (plant biomass removal) on different levels of biological organization. I ran a 4-year field experiment in which I manipulated water availability, temperature and clipping in three different grassland types. I found complex plant community structure and biomass response; treatments often interacted but the different grassland types had their own particular responses. As part of this experiment I monitored the effects of treatments on soil moisture and temperature and found that the effects are generally consistent with expectations, but treatments do not act exclusively or independently on target variables. In addition to stress and disturbance, competition is a key process structuring grasslands. In the greenhouse, I examined how plant competition is affected by stress and disturbance. I found that the interpretation of how competition is affected is dependent on the way competition is measured. Some measures of competition showed reduced competition across stress and disturbance gradients, but other measures showed no change. Finally, I examined the root traits of 18 species of grass in the greenhouse in response to reduced water availability. I found significant variation in traits among species, maintenance of trait hierarchies across environments and little evidence of plasticity, except for root: shoot ratio. Overall, stress, disturbance and their interactions are important in influencing individual plant performance, competition, structuring plant communities, and ecosystem function.

 I am co-supervised by Lauchlan Fraser at Thompson Rivers University in Kamloops, BC.


Folkard P, Fraser LH, Carlyle CN and Tucker R. Accepted. Forage production potential in a Ponderosa pine stand: effects of tree spacing on understory plants after 45 years. BC Journal of Ecosystems and Management.
White, SR, Carlyle CN, Fraser LH and Cahill JF. 2011. Climate change experiments in temperate grasslands: synthesis and future directions.
Biology Letters. doi: 10.1098/rsbl.2011.0956
Carlyle CN, Fraser LH and Turkington R. 2011. Tracking soil temperature and moisture in a multi-factor climate and disturbance experiment in temperate grassland:  do climate manipulation methods produced their intended effects? Ecosystems 14: 489 - 502.
Fraser LH and Carlyle CN. 2011. Is spotted knapweed (Centaurea stoebe L.) patch size related to the effect on soil and vegetation properties? Plant Ecology 212: 975 – 983.
Carlyle CN, Fraser LH and Turkington R. 2010. Using three pairs of competitive indices to test for changes in plant competition along a resource and disturbance gradient. Journal of Vegetation Science 25:1025 – 1034.
*received the 2010 Journal of Vegetation Science Editor’s Award, see Wilson et al. 2011. JVS 22: 1 – 5.
*received the J. S. Rowe Award for best published paper in plant ecology by a student at a Canadian University, Canadian Botanical Association
Carlyle CN, Haddow C, Bings B, Harrower W and Fraser LH. 2010. Use of digital photos to measure visual obstruction for wildlife in grasslands. Journal of Environmental Management 91: 1366 – 1370.
Fraser LH, Greenall AL, Carlyle CN, Turkington R and Ross-Friedman C.
2009. Adaptive phenotypic plasticity of Pseudoroegneria spicata: response of stomatal density, leaf area and biomass to changes in water supply and increased temperature.  Annals of Botany 103:769-775.
Carlyle CN and Fraser LH. 2006.  A test of three juvenile plant competitive response strategies. Journal of Vegetation Science 17:11-18.
*received the 2006 JVS Editor’s Award, see Chiarucci et al. 2007. Journal of Vegetation Science 18:1-2.
Miletti T, Carlyle CN, Picard C, Landaw A, and Fraser LH. 2005.
Hydrology, water chemistry and vegetation characteristics of a tamarack bog in Bath Township, Ohio. Ohio Journal of Science 105:21-30.