Genetic variation in flowering phenology and reproductive performance in a Mediterranean high-mountain specialist,Armeria caespitosa(Plumbaginaceae)

Abstract

Adaptive responses to past climate change may play an important role in the persistence of high-mountain plants, which are vulnerable to global warming. Armeria caespitosa is a high-mountain plant, endemic to the Iberian Central Range. Differences in abiotic environment along the elevational gradient impose two opposing stress gradients (i.e. water stress and duration of the growth season) on the species. Furthermore, the species is found in two interspersed, contrasting microhabitats (rocky outcrops and dry cryophilic grasslands) that have different effects on plants depending of the elevation. As a result of this, the species shows great among-population variation in many reproductive and vegetative traits. We used a common garden approach to determine whether this phenotypic variation has a genetic basis or is the result of plastic responses shaped by heterogeneous environmental conditions. Plants from the high-elevation edge and dry cryophilic grasslands flowered earlier and produced more viable fruits but were smaller. These results confirm that among-population variation in flowering phenology and reproductive performance traits in A. caespitosa is partially genetically based. The results also show that the stronger selection response in favour of early-flowering individuals in populations at the low-elevation edge did not correspond with the greater proportion of early-flowering individuals. Genetic variability associated with flowering onset may be relevant in coping with the impacts of ongoing global warming. © 2014 The Linnean Society of London, Botanical Journal of the Linnean Society, 2014, 176, 384–395.