John Howieson

Ecological and evolutionary resilience of iconic amphibian species to environmental change

PhD aim:

Understanding the ecological and evolutionary resilience of species to the challenges associated with long-term environmental change is a cornerstone of effective conservation and management strategies. Environmental stressors such as the salinisation of freshwater environments, as a result of climate change induced sea water inundation or from road de-icers, can have a catastrophic effect on amphibian populations. Salt resilience in amphibians has only been reported in a few species, with very few of these studies investigating the genetic mechanisms behind amphibian salt resilience, the adaptability of amphibian populations to saline or brackish environments is largely unknown. With reports of UK amphibian species such as the common toad, Bufo bufo, and palmate newt, Lissotriton helveticus, larvae being observed in coastal environments, the capacity of UK amphibian species to tolerate salt inundation is believed to be widely underreported.

PhD Objectives:

  • Identify the distribution of UK amphibians and which species are typically being found in saline environments through eDNA barcoding analyses. Samples of pond water from coastal sites provided by citizen science volunteers will be analysed using species specific primers, devised through the PhD, capable of identifying all UK amphibian species alongside the invasive alpine newt, Ichthyosaura alpestris
  • Utilise RADseq genotyping to elucidate the demographic history of populations and identify signatures of selection in the amphibian species identified in saline environments raised under differing salinities
  • Use RNAseq to identify genes differentially regulated under hyper saline conditions and identify genotypic differences within the genes in saline versus non-saline populations
  • Analyse through laboratory exposure experiments the physiological effects of salinity on individuals raised from eggs and larvae in hypersaline environments

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