Effects of ultraviolet radiation on the activity, survival, and growth of the critically endangered northern corroboree frog.

Ultraviolet radiation (UVR) is known to have lethal and sublethal impacts on amphibians, yet effects on anuran growth, development and behaviour remain understudied. As the global amphibian extinction crisis worsens, and more species enter conservation breeding programs (CBPs), there is a growing need to understand interrelationships between UVR exposure, growth, and UVR avoidance behaviour. Here, we investigate the effect of ecologically appropriate UVR levels on post-metamorphic growth and activity in the critically endangered northern corroboree frog (Pseudophryne pengilleyi). UVR was provided at one of two levels (lower UVI, ∼0.2 and higher UVI, ∼0.75), for a period of 16 weeks, spanning the first growth phase before hibernation. Daily activity was significantly lower in frogs reared under the higher UVR treatment (mean±s.e.m=26.339%±0.757) compared to those receiving the lower UVR treatment (mean±s.e.m=35.660%±0.837). Despite these differences, there was no significant difference between treatment groups in survival or growth. These findings indicate that northern corroboree frogs may have the capacity to adjust their behaviour in response to UVR and suggest that behavioural plasticity might mitigate potential negative impacts of UVR exposure. We discuss the value of this knowledge for amphibian CBPs.