Phenology is a harbinger of climate change, with many species advancing flowering in response to rising temperatures. However, there is tremendous variation among species in phenological response to warming, with native species demonstrating limited ability to track rising temperatures and adjust flowering time under global warming. Prior work at a few well-studied sites suggests that these non-responding species may be more susceptible to population declines. However, whether a failure to shift phenology in response to global change is linked to extinction events remains to be seen. We used herbarium records from across the Midwestern US to examine how the flowering and fruiting phenology of 9 confamilial pairs of locally extinct and non-extinct native species once found in Michigan prairies has shifted over the last 155 years (ca. 1860-2015) and in response to temperature over this time period.
Results/Conclusions
Locally extinct species tended to flower earlier than non-extinct species (χ2=0.56, p<0.0001). However, non-extinct species flowered earlier while locally extinct species flowered later at warmer monthly temperatures (status × temperature χ2=47.18, p<0.0001). Fruiting, meanwhile, was only sensitive to average monthly temperature (χ2=52.94, p<0.0001). These results support the hypothesis that the inability to shift flowering phenology may influence population declines, but also suggest that locally extinct species may have shifted their phenologies in the wrong direction predicted under climate warming. This study potentially implicates phenology as a mechanism underlying local extinction events.