Ultra Violet Radiation and Its Role in Frog Ecology and Evolution
Ultra violet radiation, especially UV-B radiation (280 – 320 nm), has been hypothesized to be one of the major contributing factors to the decline of amphibian populations worldwide (Gardner 2001, Houlahan et al. 2000, Keisecker et al. 2001). UV-B radiation has been known to cause an increase in the likelihood of premature death, as well as malformations and deformations in a large number of frog (order Anura) populations (Han et al. 2007, Keisecker et al. 2001, Blaustein et al 2003). While the exact effects UV-B radiation has on frog development is currently being investigated and debated, many conclusions can be drawn from past and current research. UV-B radiation by itself is a known problem, but when combined with other factors (pH, temperature, water depth, mold) it can cause a synergistic and additive effect (Bancroft et al. 2008, 2nd reference, Gardner 2001).
There has also been a variety of research investigating the role of physiological, molecular and behavioral (Han et al. 2007, Blaustein et al. 2003) adaptations in frog populations. These adaptations are in response to the recent increase in UV-B radiation on the surface of the planet, which has been caused by the recent decrease in stratospheric ozone (Bancroft et al. 2008, Diamond et al. 2002). In some cases, the size of the population may also have an influence the effects of UV-B radiation (Houlahan et al. 2000).
Effects of UV-B Radiation on Anuran species
Exposure to UV-B radiation can cause various types of lethal or sublethal effects on amphibians (Han et al. 2007). These effects include genetic deformations, improper development, various forms of skin malformations, and premature death (Diamond et al. 2002). Due to the recent decrease in stratospheric ozone and the decrease in surface water level in frog habitats, there has been a significant increase in the amount of exposure to UV-B radiation in frog populations (Bancroft et al. 2008).