Amanda Caldwell (1), Geoff While (2), Michael Kearney (3), Erik Wapstra (4)
1 School of Biological Sciences, University of Tasmania, Private Bag 5, Hobart, TAS, 7001, Mandy.Caldwell@utas.edu.au,@MandyCaldwell_
2 School of Biological Sciences, University of Tasmania, Private Bag 5, Hobart, TAS, 7001, Geoffrey.While@utas.edu.au
3 School of BioSciences, The University of Melbourne, VIC, 3010, M.Kearney@unimelb.edu.au, @ecophys
4 School of Biological Sciences, University of Tasmania, Private Bag 5, Hobart, TAS, 7001, Erik.Wapstra@utas.edu.au, @erikwapstra
Climatic changes are forecast to be greater in mountainous regions but species-specific impacts are difficult to predict. This is partly due to inter-specific variance in the physiological and behavioural traits which mediate environmental temperature effects at the organismal level. We examined variation in the critical thermal limits and evaporative water loss rates (EWL) of a widespread and two range restricted highland members of a cool temperate Tasmanian lizard genus, Niveoscincus. The widespread species had higher thermal limits and lower EWL than both highland species. Using this data we predicted a net gain in available activity time for all three species under predicted climate change. We then tested the capacity for a high and low altitude population of two widespread and two highland-restricted Niveoscincus species to respond to variation in basking opportunity through changes in basking time and selected body temperature under controlled laboratory conditions. There were population and species-specific behavioural and body temperature responses to the thermal environment which will at least partially mitigate the impact of changing temperatures on these species. We incorporated behavioural and physiological trait data into NicheMapR to mechanistically test the effects of projected climate change on Niveoscincus species life history, distribution and persistence. The models predicted the widespread species would colonise increasingly higher altitude sites under projected climate change. Highland species ranges are predicted to be progressively restricted as access to cold sites diminishes. Our study exemplifies the importance of incorporating behavioural and physiological trait variation into models of species responses to climate change.