Format: ORAL

Alexandra Seglias

Department of Research and Conservation, Denver Botanic Gardens, Denver, USA

Climate change threatens plant biodiversity worldwide. Alpine plant species are particularly vulnerable to climate change, as temperature fluctuations are projected to be most severe in high elevation areas. Even small shifts in climate can have major consequences on phenology, reproduction, fitness, and community composition. Early life stages (seed germination and seedling survival) are arguably the most important processes in not only the fitness of an individual plant, but also in the dynamics and persistence of plant populations. These initial developmental stages are expected to be more vulnerable to changes in climate than adult life stages and thereby represent a major bottleneck to recruitment and population responses as climate change increases in severity. To understand how the early life stages of alpine plant species will respond to warming temperatures, I used climate-controlled incubators at three different temperature regimes. Temperatures were based on current conditions and projected future conditions under moderate and severe scenarios. I found that two rare alpine species (endemic to the Rocky Mountains of the USA), Physaria alpina and Townsendia rothrockii, performed better under warmer temperatures as compared to control temperatures at both the germination and seedling stage. Germination proportion, number of leaves, and the length of the longest leaf were all higher on average under warm conditions for both species. The results show that early life stages of alpine plants may not be at high risk from warming temperatures, however there are many other shifting climatic factors resulting from climate change beyond temperature alone. Precipitation, snowpack, freeze/thaw cycles, and length/variability of seasons will all impact alpine species. Furthermore, it is important to understand the entire life cycle of the species and how conditions may impact plants at later life stages. Future studies aim to tease apart these considerations.