Past selection explains differentiation in flowering phenology of nearby populations of a common alpine plant

Abstract

The timing of and relative investment in reproductive events are crucial fitness determinants for alpine plants, which have limited opportunities for reproduction in the cold and short growing seasons at high elevations. We use the alpine Anthyllis vulneraria to study whether flowering phenology and reproductive allocation have been under diversifying selection, and to assess genetic diversity and plastic responses to drought in these traits. Open-pollinated maternal families from three populations in each of two regions from the Swiss Alps with contrasting precipitation were grown in low and high soil moisture in a common garden. We measured onset, peak, and end of flowering, as well as vegetative and reproductive aboveground biomass. Population differentiation for each character (Q ST ) was compared to differentiation at neutral microsatellite loci (F ST ) to test for past selection. We found population differentiation in onset and peak of flowering which results from natural selection according to Q ST -F ST . End of flowering and biomass were not significantly differentiated among populations. Reduced soil moisture had no consistent effect on mean onset of flowering, and advanced peak and end of flowering by less than 1 week. Reproductive biomass was strongly decreased by lowered soil moisture. No genetic variation within or among populations was found for plasticity in any trait measured. The results suggest past heterogeneous selection on onset and peak of flowering in alpine Anthyllis vulneraria and potentially indicate local adaptation to differences in snowmelt date over distances \5 km. Limited variation in plastic responses to reduced soil moisture suggests that soil moisture might not vary between populations.

Altitude and latitude have different effects on population characteristics of the widespread plant Anthyllis vulneraria

“…Moreover, AFLP variance in a study of eight taxa of A. vulneraria did not support recognizing intraspecific taxa of A. vulneraria at the species or subspecies level (Köster et al 2008). In contrast to earlier studies which argued that subspecies do not interbreed due to the predominantly autogamous reproductive system (Couderc 1971;Couderc and Gorenflot 1978) more recent studies based on molecular markers found that there is considerable gene flow among and within populations (Honnay et al 2006;Van Glabeke et al 2007;Kesselring et al 2015) indicating that the populations are not predominantly selfing. In the present study, we will therefore not distinguish between putative subspecies a priori to capture a large amount of variation over the whole study area.…”

Deep roots delay flowering and relax the impact of floral traits and associated pollinators in steppe plants

“…Flowering phenology obviously is constrained by the physiological constraints imposed by different seasonal environments. Seasons that are too harsh to survive are obviously too harsh to flower [ 4 ]. Among communities, flowering phenology is driven by functional traits that permit plants to sustain environmental stress and disturbance [ 5 ].…”

The divergent impact of phenology change on the productivity of alpine grassland due to different timing of drought on the Tibetan Plateau

“…In an alpine grassland of Switzerland, late reproducing plants could not mature seeds due to the shortening of the growing season by drought (Gugger et al, 2015). Drought treatment substantially reduced the reproductive biomass of alpine populations in the Swiss Alps, with advanced peak and end of flowering (Kesselring, Armbruster, Hamann, & Stöcklin, 2015).…”