Recent catastrophic global amphibian declines have been partially linked to increases in UV-B radiation as a consequence of
stratospheric ozone depletion. Previous studies have shown that in the presence of other environmental stressors including
aquatic pH and temperature and the presence of contaminants or pathogens, the lethal effects of UV-B on amphibian larvae are
enhanced due to interactions between the stressors. Little is known about the interactions between UV-B and aquatic hypoxia,
a common and significant natural stressor of amphibian larvae. We examined the potential effects of UV-B and aquatic hypoxia
in combination on embryonic survival, developmental rate, body mass and locomotor performance of embryos and larvae of the
striped marsh frog, Limnodynastes peronii. We found that while both UV-B and hypoxia independently had substantial negative effects on the developing embryos of L. peronii, they did not interact in a multiplicative or antagonistic manner. The effects of the stressors in combination were as might
be predicted based on the knowledge of their independent actions alone (i.e. an additive effect). In all cases developing
embryos exposed to both UV-B and hypoxia were more severely affected than those exposed to either UV-B or hypoxia alone. The
results of this study show the importance of examining both the direct actions of individual stressors and how these may be
influenced by the presence of other environmental factors.
Keywords Conservation physiology – Frogs – Amphibian declines – Synergistic – Tadpoles – Ultraviolet radiation
Communicated by I. D. Hume.