Date of Award

8-2013

Degree Type

Dissertation

Embargo Date

2-3-2014

Degree Name

Doctor of Philosophy (PhD)

Department

Biology

Advisor(s)

Jason D. Fridley

Keywords

Adaptation, Climate change, Functional traits, Plantago lanceolata, Plant communities, Population genetics

Subject Categories

Ecology and Evolutionary Biology

Abstract

Annual manipulations of temperature and rainfall have been maintained in intact calcareous grassland since 1993 at the Buxton Climate Change Impacts Laboratory (BCCIL) in northern England (UK). Here I investigated the role of local adaptation as mechanism of the apparent resistance of species' to long-term climate manipulations at BCCIL using a common forb, Plantago lanceolata. Plantago lanceolata is a rosette-forming, perennial herb of wide-ranging distribution, and one of the more common forbs in calcareous grasslands, including BCCIL. In the first study I used a common garden approach to test for evidence of selection for different suites of functional traits in P. lanceolata populations exposed to chronic summer drought at BCCIL. Results suggest that avoidance strategies associated with high reproductive allocation were more common in populations exposed to long term experimental drought versus populations from controls and that soil depth moderated treatment effects. In the second study I revealed significant treatment based genetic differentiation in P. lanceolata populations using molecular markers (AFLPs: Amplified Fragment Length Polymorphisms) that suggests a genetic basis for the functional differentiation evident in the common garden study. Finally I expanded environmental monitoring and trait analyses of P. lanceolata to calcareous grassland systems in the landscape surrounding BCCIL in an effort to relate the extent and spatial structure of nested landscape gradients corresponding to soil water supply and demand and the spatial structure of variation in six functional traits that reflect the main axes of functional differentiation found in the common garden study. Abiotic gradients associated with soil water dynamics had distinct spatial structures which in turn promoted the hierarchical partitioning of intraspecific functional diversity in five of the six functional traits measured. Taken together my results suggest a genetic basis for local intraspecific functional differentiation in P. lanceolata which in turn has allowed this species to adapt in situ to experimental climate manipulations. Furthermore, local and landscape scale gradients in factors related to climate change (e.g., soil moisture) promote functional trait variation at associated scales which may buffer this species from future climatic change.

Access

Open Access

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