Reproductive limits of a late‐flowering high‐mountain Mediterranean plant along an elevational climate gradient

Abstract

Summary• Mountain plants are particularly sensitive to climate warming because snowmelt timing exerts a direct control on their reproduction. Current warming is leading to earlier snowmelt dates and longer snow-free periods. Our hypothesis is that highmountain Mediterranean plants are not able to take advantage of a lengthened snow-free period because this leads to longer drought that truncates the growing season. However, reproductive timing may somewhat mitigate these negative effects through temporal shifts.• We assessed the effects of flowering phenology on the reproductive success of Silene ciliata , a Mediterranean high-mountain plant, across an altitudinal gradient during two climatically contrasting years.• The species showed a late-flowering pattern hampering the use of snowmelt water. Plant fitness was largely explained by the elapsed time from snowmelt to onset of flowering, suggesting a selective pressure towards early flowering caused by soil moisture depletion. The proportion of flowering plants decreased at the lowest population, especially in the drier year. Plants produced more flowers, fruits and seeds at the highest population and in the mild year.• Our results indicate that water deficit in dry years could threaten the lowland populations of this mountainous species, while high-altitude environments are more stable over time.

Flowering patterns of <i>Thymelaea velutina</i> at the extremes of an altitudinal gradient

“…A delay in flowering time with the increase in elevation seems to be frequent in species that can grow along altitudinal or latitudinal gradients (Silim & Omanga, 2001), and has been previously documented in Mediterranean shrublands (Arroyo, 1990 a,b,c;Giménez-Benavides & al., 2007). The delayed flowering in T. velutina in the mountain increases its reproductive success although it is lower than in the coastal dune, as flowering coincides with a greater abundance of insects at that altitude (de la Bandera & Traveset, 2006a).…”

“…In some alpine and subalpine species, phenotypic plasticity allows the high altitude populations to compensate the short growing season by reproducing more quickly than those of lower altitude (Starr & al., 2000;Stinson, 2004). Moreover, in regions influenced by Mediterranean climate, plant reproduction time is constrained by summer drought (Giménez-Benavides, 2007). In addition, García-Camacho (2009) found in Armeria caespitosa (a high mountain early-flowering species) that individuals with longer flowering periods showed significantly lower seed set and higher number of unviable seeds, which suggests that plants ripening their seeds into the summer drought have lower reproductive success.…”

Summer rainfall variability in European Mediterranean mountains from the sixteenth to the twentieth century reconstructed from tree rings

“…Here, the cause of stress is fundamentally water related (Kramer et al 2000;Giménez-Benavides et al 2007;Acosta et al 2008) and warming and desiccation would cause radical re-ordination of plant communities in these mountains. Since the end of the last glaciation, relict Mediterranean populations of Eurosiberian and Boreal species that have found refuge in these mountains constitute one of the southernmost formations of these species in Eurasia.…”

Individual spatial aggregation correlates with between-population variation in fine-scale genetic structure of Silene ciliata (Caryophyllaceae)

“…It is self-compatible, although autogamy is restricted by pronounced protandry (García-Fernández et al, 2012). It blooms in late summer (Gimenez-Benavides et al, 2007) and its flowering stems reach 15 cm in height and have 1-5 flowers. S. ciliata is pollinated at night by Hadena consparcatoides Schawerda (Lepidoptera, Noctuidae) but can also be pollinated by diurnal insects (Gimenez-Benavides et al, 2007).…”

“…It blooms in late summer (Gimenez-Benavides et al, 2007) and its flowering stems reach 15 cm in height and have 1-5 flowers. S. ciliata is pollinated at night by Hadena consparcatoides Schawerda (Lepidoptera, Noctuidae) but can also be pollinated by diurnal insects (Gimenez-Benavides et al, 2007). Fruit capsules contain up to 100 seeds that are wind dispersed in August-September.…”