The Role of Phenotypic Plasticity and Local Adaptation in Alpine Plants Facing Climate Change
Total Page：16
File Type：pdf, Size：1020Kb
THE ROLE OF PHENOTYPIC PLASTICITY AND LOCAL ADAPTATION IN ALPINE PLANTS FACING CLIMATE CHANGE INAUGURALDISSERTATION zur Erlangung der Würde eines Doktors der Philosophie vorgelegt der PHILOSOPHISCH-NATURWISSENSCHAFTLICHEN FAKULTÄT der Universität Basel von ELENA HAMANN Aus Oldenburg, Deutschland Basel, 2017 Originaldokument gespeichert auf dem Dokumentenserver der Universität Basel edoc.unibas.ch Dieses Werk ist unter dem Vertrag „Creative Commons Namensnennung-Keine kommerzielle Nutzung-Keine Bearbeitung 3.0 Schweiz“ (CC BY-NC-ND 3.0 CH) lizenziert. Die vollständige Lizenz kann unter creativecommons.org/licenses/by-nc-nd/3.0/ch/ eingesehen werden. Genehmigt von der Philosophisch-Naturwissenschaftlichen Fakultät auf Antrag von Prof. Dr. Jürg Stöcklin Dr. Andrea Plüss Basel, den 10. November 2015 Prof. Dr. J. Schibler Dekan “A garden requires patient labor and attention. Plants do not merely grow to satisfy ambitions or to fulfill good intentions. They thrive because someone expanded effort on them.” - Liberty Hyde Bailey __________ “If we knew what it was we were doing, it would not be called research, would it?” - Albert Einstein __________ “[…] Find out the cause for this effect, / Or rather say, the cause of this defect, / For this effect defective comes by cause. “ – Polonius (Act2, Scene 2, line 104) Hamlet, Shakespeare Contents Contents Chapter 1 General Introduction 7 Chapter 2 Lower plasticity exhibited by high- versus mid-elevation species in 21 their phenological responses to manipulated temperature and drought S. Gugger, H. Kesselring, J. Stöcklin, E. Hamann* Chapter 3 Plant responses to simulated warming and drought: a comparative 45 study of functional plasticity between congeneric mid and high elevation species E. Hamann*, H. Kesselring, J. Stöcklin Chapter 4 Past selection explains differentiation in flowering phenology of 67 nearby population of a common alpine plant H. Kesselring, G.F.J. Armbruster, E. Hamann, J. Stöcklin Chapter 5 Evidence of local adaptation to fine- and coarse-grained 91 environmental variability in Poa alpina in the Swiss Alps E. Hamann*, H. Kesselring, G.F.J. Armbruster, J.F. Scheepens, J. Stöcklin Chapter 6 High intraspecific phenotypic variation, but little evidence for local 111 adaptation in Geum reptans populations in the Central Swiss Alps E. Hamann*, H. Kesselring, G.F.J. Armbruster, J.F. Scheepens, J. Stöcklin Chapter 7 Spatial patterns of local adaptation in two common herbs from the 133 Central European Alps H. Kesselring, J.F. Scheepens, E. Hamann, G.F.J. Armbruster, J. Stöcklin Chapter 8 Novel microsatellite markers for the high-alpine Geum reptans 153 (Rosaceae) E. Hamann*, H. Kesselring, J. Stöcklin, G. F. J. Armbruster Chapter 9 New microsatellite markers for Anthyllis vulneraria (Fabaceae), 163 analyzed with Spreadex gel electrophoresis H. Kesselring, E. Hamann, J. Stöcklin, G. F. J. Armbruster Chapter 10 General Discussion 173 Acknowledgements 181 Curriculum Vitae 183 5 6 Chapter 1 Chapter 1 General Introduction 7 General Introduction 8 Chapter 1 General Introduction Lectori salutem, flora clearly distinct of that of lowlands (Chapin and Koerner, 1995). Before introducing the general aims, the Climate change, well illustrated in Europe main research questions, the experimental by increasing temperatures and changes in approach and the outline of this thesis, I precipitation patterns, has been reported by would like to set its research frame, which the IPCC (Kovats et al., 2014) and it has revolves in the scientific field of plant been suggested that these effects are population and evolutionary biology. For this proportionally more pronounced at high purpose, I will first provide information elevation (Beniston et al., 1997). Indeed, in about the environment of the Swiss Alps, its alpine regions the amplitude of temperature flora, and how it is threatened by climate changes are greater then the observed global change. I will then proceed to introduce changes (Beniston et al., 1994). While a terms such as evolution, natural selection, 0.7°C rise in air temperatures has been local adaptation, and phenotypic plasticity. reported globally, a 2°C change in temperature has been recorded in the Alps The Alpine flora and environment is (Auer et al., 2007). Additionally, summer threatened by climate change droughts are predicted to become more frequent in many regions including mountain areas (Kovats et al., 2014), leaving mountain Alpine biodiversity is particularly rich and biota particularly vulnerable to climate the flora of the Alps comprises about 4’000 change (Theurillat and Guisan, 2001, Körner, species (Aeschimann et al., 2004) and 2003). includes more than five hundred endemic In this context, it becomes increasingly species, i.e. unique to a particularly mountain important to investigate how the alpine flora region, where they have probably evolved. will respond to environmental changes and Plants had to adapt to the particular evolve in a future climate. environmental conditions at high altitude (Körner, 2003). With increasing elevation, plant life is challenged in many ways, by A brief introduction to local extreme temperatures, a short vegetation adaptation and phenotypic plasticity period, snow, and by a rising number of weather-related extreme events (Körner, Evolution, the heritable change over time 2003). The alpine landscape is also in the phenotype of an organism (Darwin, characterized by great spatial and temporal 1859) and natural selection, the process environmental heterogeneity, creating a which selects for particular phenotypic mosaic of micro-habitats (Scherrer and variants in a population, have led to the Körner, 2010, Scherrer and Körner, 2011). adaptation of plants to their environment. The environmental heterogeneity, along with Within a species, populations may the richness of endemics, highlights the genetically differ through natural selection or strength of selective forces and evolutionary random processes such as genetic drift. In processes in the alpine landscape (Ozenda, widespread plants, the heterogeneity of 1988, Kadereit et al., 2008), making alpine habitat conditions over large spatial scales 9 General Introduction may lead to changes in the selection from local adaptation, phenotypic plasticity pressures acting on functional plant traits and or a combination of both (Conner and Hartl, may thereby result in adaptive genetic 2004, Ghalambor et al., 2007, Franks et al., variation in a way that maximizes fitness in 2014). However, intraspecific differentiation different environments (Briggs and Walters, in alpine plants is also strongly affected by 1997). Indeed, widespread species show high the repeated oscillations during glaciations levels of variation (Bradshaw, 2006), and (Scheepens and Stöcklin, 2011, Scheepens et frequently perform well in a wide range of al., 2015). Thus, to some extent, phenotypic environmental conditions (Joshi et al., 2001, differentiation in alpine plants may be Santamaria et al., 2003). On the one hand, ecologically relevant and adaptive, but to adaptations to climatic variation or other some degree it may result from random conditions that differ at a larger spatial scale evolutionary processes (e.g. genetic drift). (coarse-grained environmental variation) There are not many studies on alpine plants should easily be maintained by natural that have rigorously tested hypotheses selection, while genetic adaptations to concerning local adaptation, either for environmental variability at a more local elevational effects (Galen and Stanton, 1991, scale (fine-grained environmental variation) Byars et al., 2007, Byars and Hoffmann, may be hindered by gene flow (Kawecki and 2009, Hautier et al., 2009), differences in Ebert, 2004). Since the pioneer studies of snow cover (Stanton and Galen, 1997), or Turesson (1922) and Clausen et al. (1941), adaptation to contrasting habitats (McGraw, patterns of intraspecific variability were the 1987, Leinonen et al., 2009). Mostly, local focus of many studies, and specialization to adaptation in these studies was demonstrated particular environmental conditions has been across wide climatic or elevational gradients frequently demonstrated (Van Tienderen, or to contrasting habitats, but populations 1991, Dudley, 1996, Van Tienderen, 1997, were rarely transplanted across their original Pluess and Stöcklin, 2005, Fischer et al., field sites. At the local scale genetic 2008). adaptation to environmental variability may As a result, it is usually assumed that be hampered by gene flow or source sink plants are locally adapted. Local adaptation is relations among nearby populations (Stanton characterized by adaptive differentiation and Galen, 1997, Kawecki and Ebert, 2004). among populations. Plants can be locally Nevertheless, differentiation among alpine adapted either constitutively via genotypic populations has also been demonstrated at differences or via phenotypic plasticity, the micro-scale, indicating the strength of which is the range of phenotypes a single small-scale heterogeneity as a selective force genotype can express as a function of its for local adaptation (Shimono et al., 2009). environment (Bradshaw, 1965). Genotypic In other cases, adaptation to small-scale variability and phenotypic plasticity can be environmental heterogeneity was missing considered as complementary mechanisms (Byars et al., 2009). Furthermore, local adjusting plants to environmental adaptation is also contingent on factors other heterogeneity (Van Tienderen, 1991, Van than spatial scale, such