To investigate recent coastal and inland range expansions of UK coastal halophytes the student will:
A. Compile a historical and current distribution database for coastal halophytes in the UK. We will work with the Botanical Society of the British Isles (BSBI), who maintain the UK’s highest quality plant recording databases.
B. Conduct a standardised analysis of the extent of coastal and inland range expansions to assess overall range trends of halophytes in both environments (e.g. number of grid cells colonised post 2000, northwards or inland spread distance).
C. Test for a positive relationship between the extent of coastal and inland range expansion across species.
To identify the factors promoting coastal and inland range expansion the student will:
A. Compile a database of species’ traits and a phylogenetic tree for the studied halophytes. Traits will be assembled from existing databases (eHALOPH, PlantAtt, etc.) and focus on characteristics related to life history (e.g. longevity), dispersal (e.g. seed number and mass), stress tolerance (e.g. Ellenberg values) and biogeography (e.g. coastal range size, habitat use).
B. Use phylogenetic methods to model range expansion as a function of these traits, while accounting for shared evolutionary history. Model comparison will allow us to isolate the most important traits and test whether related species have similar range shift ability.
To test for evolutionary adaptation to novel inland road environments the student will:
A. Establish a multi-generational common garden experiment for the highly successful inland invader Danish scurvygrass (Cochlearia danica). To collect seed the student will make overseas trips and coordinate with collaborators from across its European coastal range (Portugal to Norway) and inland range (UK to Hungary).
B. Test for genetic differentiation in life history traits (phenology, growth strategy, fecundity) and their correlation to environmental conditions at the collection sites. Winter temperature tolerance and dispersal related traits may be those most likely to have been selected during inland range expansion.
C. Test whether plants from inland populations have improved growth performance on roadside vs coastal soils, consistent with adaptation to novel environmental conditions.