The role of phenotypic plasticity and local adaptation in alpine plants facing climate change

• Main Author: Hamann, Elena
• Other Authors: Stöcklin, Jürg, Pluess, Andrea R.
• Format: Thesis
• Language: English
• Published: 2015
• Subjects: Poa alpina
• Online Access: http://edoc.unibas.ch/diss/DissB_12423; https://edoc.unibas.ch/56649/; https://edoc.unibas.ch/56649/1/EH_eV.pdf; https://doi.org/10.5451/unibas-006779681

The Alpine landscape is characterized by great spatial and temporal heterogeneity, to which plants may have adapted constitutively (i.e. genetically) or via adaptive phenotypic plasticity. Additionally, the Alpine biota is currently facing the effects of ongoing climate change. In this context, the main aim of this Thesis was to investigate the adaptive potential of Alpine plants when facing climate change, by studying their capacity to respond plastically to environmental changes and the extent to which populations are locally adapted. A first experiment assessed the plastic responses of alpine species in key functional traits to manipulated warming and drought. We found that alpine species induced considerable shifts in their flowering phenology in response to warming and drought, and seemed to adequately follow ongoing changes. However, the phenological plasticity in flowering phenology was constrained in high- relative to low-elevation species, reflecting their specific adaption to short growing seasons at high elevation. In other key functional traits (i.e. SLA, biomass allocation to belowground or reproductive structures), high elevation species harbored the same potential for phenotypic plasticity as their low elevation congeners, globally suggesting a high capacity to respond to ongoing climate changes. A second experiment, relying on reciprocal transplantations of populations across their original field sites in the Swiss Alps, was designed to investigate the extent of local adaptation in two Alpine species. Strong evidence was found for local adaptation in Poa alpina, and the patterns of local adaptation were trait-dependent and followed different spatial scales. In contrast, little evidence for local adaptation was found in populations of Geum reptans, suggesting a lack of divergent selection across glacier forelands, the typical habitat of this species. The combination of our results i.e. the simultaneous occurrence of genetic population differentiation (i.e. local adaptation) and adaptive plastic ...