title: Lower plasticity exhibited by high- versus mid-elevation species in their phenological responses to manipulated temperature and drought.
abstract: OBJECTIVE
  Recent global changes, particularly warming and drought, have had worldwide repercussions on the timing of flowering events for many plant species. Phenological shifts have also been reported in alpine environments, where short growing seasons and low temperatures make reproduction particularly challenging, requiring fine-tuning to environmental cues. However, it remains unclear if species from such habitats, with their specific adaptations, harbour the same potential for phenological plasticity as species from less demanding habitats.
  
  
  METHODS
  Fourteen congeneric species pairs originating from mid and high elevation were reciprocally transplanted to common gardens at 1050 and 2000 m a.s.l. that mimic prospective climates and natural field conditions. A drought treatment was implemented to assess the combined effects of temperature and precipitation changes on the onset and duration of reproductive phenophases. A phenotypic plasticity index was calculated to evaluate if mid- and high-elevation species harbour the same potential for plasticity in reproductive phenology.
  
  
  RESULTS
  Transplantations resulted in considerable shifts in reproductive phenology, with highly advanced initiation and shortened phenophases at the lower (and warmer) site for both mid- and high-elevation species. Drought stress amplified these responses and induced even further advances and shortening of phenophases, a response consistent with an 'escape strategy'. The observed phenological shifts were generally smaller in number of days for high-elevation species and resulted in a smaller phenotypic plasticity index, relative to their mid-elevation congeners.
  
  
  CONCLUSIONS
  While mid- and high-elevation species seem to adequately shift their reproductive phenology to track ongoing climate changes, high-elevation species were less capable of doing so and appeared more genetically constrained to their specific adaptations to an extreme environment (i.e. a short, cold growing season).
authors.affiliation: Institute of Botany, Department of Environmental Sciences, Section Plant Ecology, University of Basel, Schönbeinstrasse 6, CH-4056 Basel, Switzerland.
authors.forename: Simona
authors.initials: S
authors.lastname: Gugger
authors.affiliation: Institute of Botany, Department of Environmental Sciences, Section Plant Ecology, University of Basel, Schönbeinstrasse 6, CH-4056 Basel, Switzerland.
authors.forename: Halil
authors.initials: H
authors.lastname: Kesselring
authors.affiliation: Institute of Botany, Department of Environmental Sciences, Section Plant Ecology, University of Basel, Schönbeinstrasse 6, CH-4056 Basel, Switzerland.
authors.forename: Jürg
authors.initials: J
authors.lastname: Stöcklin
authors.affiliation: Institute of Botany, Department of Environmental Sciences, Section Plant Ecology, University of Basel, Schönbeinstrasse 6, CH-4056 Basel, Switzerland elena.hamann@unibas.ch.
authors.forename: Elena
authors.initials: E
authors.lastname: Hamann
mesh_terms: D000222:Adaptation, Physiological; D000531:Altitude; D002980:Climate; D057231:Climate Change; D055864:Droughts; D017753:Ecosystem; D004777:Environment; D035264:Flowers / Q000502:physiology*; D010641:Phenotype; D018521:Plant Physiological Phenomena; D010944:Plants; D012098:Reproduction; D012621:Seasons; D013557:Switzerland; D013696:Temperature
keywords: Climate change; Swiss Alps; common garden; drought; flowering phenology; global warming; mid-elevation and high-elevation species; phenotypic plasticity