The Plasticity Paradox

While studies often assume that behavioral flexibility protects species from climate change, rapid warming is disrupting the cues elk use to time their movements. In the Ya Ha Tinda system, elk exhibit three distinct migratory tactics across a steep environmental gradient. This project investigated whether these divergent strategies allow elk to track shifting forage or if they create a "phenological trap" that leads to demographic decline.

I integrated 22 years of longitudinal GPS monitoring data (2002 to 2024) with satellite-derived NDVI and Bayesian mixed-effects models. I validated a Random Forest machine learning approach to estimate parturition timing from movement metrics. This allowed for the reconstruction of reproductive histories for 358 elk-years without the need for direct field observation.

I identified a phenological trap driven by the decoupling of seasonal resource cues. While western migrants maintain a fixed schedule, eastern migrants exhibit high plasticity and are delaying their spring migration by 2.7 days per year. This delay is a response to a forage productivity threshold on the winter range that is reached progressively later each year, even as the summer destination greens up earlier. This mismatch resulted in a 42% decrease in summer calf survival odds per standard deviation of mismatch.

Research findings led to a lead-author book chapter published in Nutritional Ecology of Wild Mammalian Herbivores through Johns Hopkins University Press. There are currently multiple manuscripts in progress focusing on behavioral plasticity and trophic mismatch. I presented this work at the Ecological Society of America (ESA) in Portland and at the 2026 meeting of the Alberta Chapter of The Wildlife Society (ACTWS).

Caitlin Kupar