Grant: Discovery Grants Program - Individual

The timing of yearly events in a plant's life, such as the emergence of leaves or flowers, has important consequences for how those plants perform and how they interact with other populations and other species. Since the timing of such events ("phenology") is sensitive to climatic conditions, we expect potentially important ecological consequences of climate change acting through phenology. However, testing hypotheses involving year-to-year climate fluctuations climate requires long-term data, which is rare in ecology. My central objective is to test hypotheses concerning causal links between climate, phenology, plant fitness, and species interactions. Over the next 5 years, long-term monitoring plots for plant flowering and a network of automated cameras for vegetative phenology will be extended to durations of 15 and 10 years, respectively. Analyses of these data, along with targeted experiments manipulating hypothesized causal factors, will permit mechanistic understanding of the causes and consequences of plant phenology. The outcome will be major advances in fundamental ecological understanding, with benefits both to science and to Canada via an improved basis for forecasting the ecological consequences of climate change. The research takes place in Parc national du Mont Mégantic, Québec, where low-elevation temperature deciduous forest is dominated by sugar maple, and high-elevation boreal forest is dominated by balsam fir and red spruce. The focus is largely on understory plants that emerge in early spring and that take advantage of a 4 to 5-week period of high light, prior to the expansion of canopy tree leaves. There are 3 research themes. Theme 1 focuses on flowering phenology and will first test the hypotheses that (i) flowering time is most sensitive to snowmelt, (ii) climate warming will cause reduced potential for gene flow across populations at different elevations, and (iii) climate warming is associated with novel combinations of plant species that flower simultaneously. Subsequent experimental studies will test for potential consequences of altered phenology (e.g., for plant-pollinator interactions). Theme 2 focuses on vegetative (leaf) phenology and will first test the hypothesis that the duration of the high-light period for spring understory plants will increase with climate warming. Theme 3 will use manipulative experiments to test causal factors (e.g., snowmelt, temperature, day length) that potentially underlie patterns observed in the field for both flowering and vegetative phenology. The proposed research program involves production of a landmark long-term data on plant phenology, with a unique combination of high temporal resolution, detailed data on flower or plant numbers and sizes (rather than only presence), and coverage of a steep climatic (elevational) gradient. Combined with the targeted experimental studies, the results will permit major scientific advances.