Plant local adaptation and environmental change : patterns, processes and impacts

Understanding how local adaptation arises within species is essential when making predictions about how populations may respond to environmental change. Serpentine soils present an ideal system to study the processes leading to local adaptation in plant populations. Theses soils have a scattered distribution, are deficient in several nutrient minerals, have high heavy metal content, and a poor water holding capacity; all factors contributing to a strong selective pressure against plant growth. This thesis investigates local adaptation to serpentine soil in populations of Arabidopsis lyrata ssp. petraea, a perennial of low competition habitats and which within Scotland occurs both on and off serpentine soil. Trait measures were made of plants from twelve populations across the species’ Scottish range to explore if there are trait patterns which are particular to the serpentine sites, finding that climatic and soil factors both contributed to observed trait patterns. In a controlled growth room experiment the response of five of the populations to growth on serpentine and non-serpentine soil treatments was assessed to determine if trait differences were the result of local adaptation. Plants from serpentine populations survived and performed well on all treatments, while non-serpentine plants showed reduced survival and poor growth on serpentine soil. Combined with patterns of differentiation in microsatellite markers indicating that there is not a single serpentine genetic strain of Scottish A. l. petraea it appears that serpentine populations have adapted to serpentine soil, and separately more than once. Finally, an individual based computer model was developed to explore the evolutionary consequences of local adaptation in a changing environment, finding that the strength of local adaptation, gene flow, and population size are all important determinants of population survival. These results have implications for conservation management practices used to protect small populations in changing environments; especially where local adaption is likely.EThOS - Electronic Theses Online ServiceGBUnited Kingdo