TitleUV REPAIR AND RESISTANCE TO SOLAR UV-B IN AMPHIBIAN EGGS - A LINK TO POPULATION DECLINES
Publication TypeJournal Article
Year of Publication1994
AuthorsBlaustein, AR, Hoffman, PD, Hokit, DG, Kiesecker, JM, Walls, SC, Hays, JB
JournalProceedings of the National Academy of Sciences of the United States of America
Volume91
Pagination1791-1795
Type of ArticleJournal Article
ISSN0027-8424
Abstract

The populations of many amphibian species, in widely scattered habitats, appear to be in severe decline; other amphibians skew no such declines. There is no known single cause for the declines, but their widespread distribution suggests involvement of global agents-increased UV-B radiation, for example. We addressed the hypothesis that differential sensitivity among species to UV radiation contributes to these population declines. We focused on species-specific differences in the abilities of eggs to repair UV radiation damage to DNA and differential hatching success of embryos exposed to solar radiation at natural oviposition sites. Quantitative comparisons of activities of a key UV-damage-specific repair enzyme, photolyase, among oocytes and eggs from 10 amphibian species were reproducibly characteristic for a given species but varied > 80-fold among the species. Levels of photolyase generally correlated with expected exposure of eggs to sunlight. Among the frog and toad species studied, the highest activity was shown by the Pacific treefrog (Hyla regilla), whose populations are not known to be in decline. The Western toad (Bufo boreas) and the Cascades frog (Rana cascadae), whose populations have declined markedly, showed significantly lower photolyase levels. In field experiments, the hatching success of embryos exposed to UV radiation was significantly greater in H. regilla than in R. cascadae and B. boreas. Moreover, in R. cascadae and B. boreas, hatching success was greater in regimes shielded from W radiation compared with regimes that allowed UV radiation. These observations are thus consistent with the UV-sensitivity hypothesis.

URL<Go to ISI>://WOS:A1994MZ09400041
DOI10.1073/pnas.91.5.1791