Amphibian populations are declining across the globe at an unprecedented rate. Climate change and disease are emerging as the most commonly cited causes of enigmatic declines: those where suitable habitat remains and causes are not completely understood. Climate change has had detectable effects on breeding phenology of amphibians, with a pattern for earlier breeding seen in the UK. In the tropics, several amphibian taxa previously restricted to lower altitudes have ascended higher into the mountains, with distribution shifts to higher latitudes and higher altitudes observed in a range of species worldwide. Temperature changes are expected to particularly affect ectotherms, leaving amphibians vulnerable to decline.

Altitudinal gradients show rapid changes in environmental variables, such as temperature and humidity, even over short geographical distances. Therefore, mountains offer the ideal opportunity to assess how the environment has influenced fitness related traits within a species. The common frog, Rana temporaria, occurs from sea level to over a 1000m at the top of Scotland’s highest mountains. Looking at whether, and in what way, populations of the common frog have adapted to the different temperature regimes along an altitudinal gradient will allow us to make predictions about how they will be affected by ongoing climate change.

The aim of my current research is to assess the potential for, and presence of, local adaptation in populations of the common frog. Specifically, it will quantify the temperature differences experienced by populations at different altitudes and assess levels of dispersal between these populations. It will determine if populations are locally adapted and to what extent local adaptation has taken place in terms of key temperature-related fitness traits. Finally, it will assess the species diversity of a water mould that causes egg mortality, Saprolegnia, and how diversity varies between amphibian populations and in relation to environmental factors.

The output of this work will provide a clearer understanding of how common frogs have responded to different temperature regimes, thereby facilitating creation of knowledge-based action plans for climate change and conservation strategies.

This work is a collaboration between the University of Glasgow, supervised by Dr. Barbara Mable, and the Royal Zoological Society of Scotland, based at Edinburgh Zoo.

Biotechnology and Biological Science Research Council The Royal Zoological Society of Scotland Glasgow Natural History Society

The Scottish Moutaineering Trust