The timing of snowmelt and amount of winter precipitation have limited influence on flowering phenology in a tallgrass prairie

Abstract

A growing body of work indicates that the timing of flowering of temperate angiosperms has been affected by shifts in climate since the 1970s. Sensitivity in flowering phenology to changing temperatures has been particularly well-documented, but widespread phenological sensitivity to changing precipitation patterns in temperate communities has only been shown in a few studies. The exception is relationships between snowpack and early flowering in alpine environments, whereby the timing of flowering herbs had strong associations with winter precipitation and the snowmelt timing. Based on these results, we hypothesized that populations in temperate latitudes characterized by strong seasonality and winter snowfall would demonstrate associations between timing of snowmelt and flowering phenology. We combined a historical dataset of first flowering dates in a Minnesota tallgrass prairie with climatic data to construct a structural equation model, testing hypotheses on the relationships between winter precipitation, temperature, and flowering phenology. While temperature had a strong effect on flowering phenology, winter precipitation had a significant relationship with only a few species. The species affected by snow were later flowering species, which is inconsistent with our prediction that winter precipitation affects early flowering phenology. These results suggest future changes in precipitation will have differing consequences depending on region.