As part of an overall decline in biodiversity, populations of many organisms are declining and species are being lost at unprecedented rates around the world. This includes many populations and species of amphibians. Although numerous factors are affecting amphibian populations, we show potential direct and indirect effects of climate change on amphibians at the individual, population and community level. Shifts in amphibian ranges are predicted. Changes in climate may affect survival, growth, reproduction and dispersal capabilities. Moreover, climate change can alter amphibian habitats including vegetation, soil, and hydrology. Climate change can influence food availability, predator-prey relationships and competitive interactions which can alter community structure. Climate change can also alter pathogen-host dynamics and greatly influence how diseases are manifested. Changes in climate can interact with other stressors such as UV-B radiation and contaminants. The interactions among all these factors are complex and are probably driving some amphibian population declines and extinctions.

Numerous factors, such as global environmental changes, habitat destruction, introduced species, diseases, and chemical pollution, appear to be contr

Habitat use by animals often reflects the balance between conflicting demands such as foraging and avoiding predation. Environmental stressors such as temperature can also affect habitat use in many organisms, particularly in ectothermic animals. For example, warm, shallow thermal regimes in ponds can optimize growth and developmental rate of amphibian larvae but may also expose larvae to potentially harmful levels of ultraviolet B (UVB) radiation. Thus, optimally, amphibians seeking sunlight for thermoregulation must balance this behavior while limiting their exposure to harmful UVB radiation. We conducted a series of laboratory and field experiments to test the hypothesis that larval amphibians avoid UVB by selecting microhabitats with lower exposure to UVB. We then quantified habitat use of the larvae of 4 amphibian species using field transects in 3 ponds with different UVB transmission. Tadpoles did not avoid UVB radiation in laboratory or field experiments and preferred warmer temperatures in laboratory thermal gradients regardless of UVB exposure. The majority of anuran larvae were observed in water less than 10–15 cm deep in field surveys, whereas salamander larvae were most often observed in deeper, cooler water. The similarity in habitat use across different sites and the lack of evidence of UVB avoidance in choice tests suggest that larval anuran amphibians may be exposed to harmful levels of UVB radiation due to habitat choice behaviors that have been established over evolutionary time. Levels of UVB radiation at the earth's surface have recently increased due to stratospheric ozone depletion. Thus, long-term selection pressures such as thermoregulation may override the relatively recent selection pressure of increased UVB radiation.