In the face of rapid global change, a crucial question in ecology and evolution is how species will respond to changes in climate and whether they will be able to adapt quickly enough to persist under novel abiotic conditions. Changes in phenology are already occurring due to climate change and have the potential to influence species interactions, community structure, population genetics, and biodiversity. However, little is known about how within-species differences in phenology affect adaptation and persistence. Here, we examine population-level responses to snowmelt timing and herbivory regime in Streptanthus tortuosus, which occupies a wide range of environments and displays remarkable variation in morphological and life history traits. We conducted an observational study across six mountain populations of S. tortuosus at Lassen Volcanic National Park, which exhibits strong spatial variation in snowmelt timing within and across elevations and thus offers an opportunity to decouple the effects of temperature, snowmelt, and elevation on phenology.
Results/Conclusions
Our results suggest that snowmelt timing significantly affects both flowering time and herbivory regime experienced by the plant. Individuals in plots that experienced earlier snowmelt flowered earlier and were more likely to experience herbivory. Further, preliminary results suggest that later snowmelt depresses fecundity, which may indicate that flowering earlier leads to greater fitness despite increased exposure to herbivory. Future plant phenological responses to climate change will depend on how these factors interact with changing environmental conditions, and whether populations can adapt to shifting regimes. Warming temperatures are causing a decrease in snowpack and an acceleration in the onset of snowmelt in alpine regions, with consequences such as advanced phenology, an increase in flowering season length, reduced late-season water availability, and the potential for overall increased spatiotemporal overlap in phenology. Understanding the abiotic and biotic factors that currently drive phenological responses is essential for accurately predicting the potential for adaptation to future climate-induced environmental change.