Electronic supplementary Table 1: Critical gaps in our knowledge of alpine seed and seedling ecology. Filling these gaps will help us to understand and predict the effect of warming and reduction of snow cover on alpine plant regeneration by seed. These questions need to be approached at different scales: both between species comparisons and comparisons between populations of the same species, particularly from contrasting microhabitats (e.g low land versus high elevation; snowbeds versus fellfields; wet versus dry alpine microenvironments). The approaches recommended here have been applied previously in other ecosystems, not necessarily in alpine areas.

Critical questions / Recommended methodology
1.  Seed production and pre-dispersal and dispersal effects / a.  Will the new thermal conditions during seed development have carry-over effects on seeds (size and germination) and seedling performance (growth and survival)?
b.  Will the new thermal conditions during seed development have carry-over effects on seed longevity?
c.  Will climate change interfere on seed dispersal? / a.  Exposing plants to simulated climate change conditions and evaluating its effect on seed size germination and seedling performance (Klady et al. 2011)
b.  Controlled aging experiments on seeds produced under contrasting (cold, warm) paternal conditions (Kochanek et al. 2010; Mondoni et al. 2014b)
c.  Modelling seed dispersal under current and future climate (Engler & Guisan 2009; Mokany et al. 2014)
2.  Soil seed bank / Will warming, coupled with increases in freeze/thaw cycles, interfere with:
a.  viability
b.  longevity
c.  predation
d.  germination
of seeds from the soil seed bank? / a.  Exposure of seeds at different moisture content to subzero temperatures (Hawkins et al. 2003; Marcante et al. 2012)
b.  Controlled aging experiments (Long et al. 2008)
c.  Soil and seeds reciprocal transplant along the elevational gradient (Brown & Vellend 2014)
d.  Ex situ germination of soil seed bank samples mimicking alpine future soil temperatures (Venn & Morgan 2010) or In situ seed burial experiments (Cavieres & Arroyo 2001).
3.  Germination phenology / a.  How might warming and altered frequency of subzero temperatures interfere with germination phenology? Will these factors advance, delay, increase or decrease germination? / a.  Exposure of seeds to conditions that mimic soil warming and freezing events (Mondoni et al. 2012; Hoyle et al. 2013)
4.  Seedling survival and establishment / a.  How well can seedlings of different species tolerate freezing and heating events?
b.  Does seedling thermo-tolerance differ depending on germination strategy of species?
c.  Will shifts in germination phenology move seedlings out of their physiological tolerances? / a.  Expose seedlings to freezing and heating events and monitor survival or damage to photosynthetic apparatus (Buchner & Neuner 2003; Shevtsova et al. 2009; Sierra-Almeida & Cavieres 2012; Briceño et al. 2014)
b-c. Compare the tolerance to freezing and heating events of seedlings that differ in germination strategies (e.g seedlings that emerge in summer versus seedlings that emerge in winter under snow)