Dryad
Rivest, Sébastien;
Lajoie, Geneviève;
Watts, David;
Vellend, Mark
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2021-03-20
<p style="text-align:justify;"><b>Premise</b>: One of the best-documented ecological responses to climate warming involves temporal shifts of phenological events. However, we lack an understanding of how phenological responses to climate change vary among populations of the same species. Such variability has the potential to affect flowering synchrony among populations and hence the potential for gene flow.</p>
<p style="text-align:justify;"><b>Methods</b>: To test if an earlier start of the growing season affects the potential for gene flow among populations, we quantified the distributions of flowering times of two spring-flowering plants (<i>Trillium erectum</i> and <i>Erythronium americanum</i>) over six years along an elevation gradient. We developed a novel model-based metric of potential gene flow between pairs of populations to quantify the potential for pollen-mediated gene flow based on flowering phenology.</p>
<p style="text-align:justify;"><b>Results</b>: For both species investigated, earlier onset of spring led to greater separation of peak flowering dates across the elevation gradient. For <i>T. erectum</i>, but not <i>E. americanum</i>, this<i> </i>was also associated with a reduction in potential gene flow.</p>
<p style="text-align:justify;"><b>Conclusion</b>: Our study suggests that climate change could decrease gene flow via phenological separation among populations along climatic gradients. We also provide a novel method for quantifying potential pollen-mediated gene flow using data on flowering phenology, based on a quantitative, more biologically interpretable model than other available metrics.</p>