Meeting Abstract
Salinization of freshwater habitats is an increasing environmental concern. Rising sea level, storm surge, deicing salts, and other forms of habitat modification can contribute to increased salinity in freshwater ecosystems. Elevated salinity can increase the demands of osmoregulation in freshwater organisms, and amphibians are particularly at risk due to their aquatic development and permeable skin. The typical anuran life cycle requires freshwater for fertilization as well as embryonic and tadpole development. Determining the salinity tolerance of these three life stages is important for identifying stages that are at greatest risk due to habitat salinization. However, most studies have focused on a single life stage, and salinity effects on fertilization have seldom been tested. We investigated the effects of a range of salinities on fertilization, embryos and tadpoles of the squirrel tree frog, a species found in the coastal plain of the southeastern US. Although increased salinity had negative effects on each life stage, the embryo stage was the most sensitive, with complete mortality at a salinity that allowed some fertilization and some tadpole survival. Unexpectedly, however, tadpole survival was significantly reduced in the lowest (control) salinity level, suggesting that squirrel tree frogs may require additional solutes during larval development. Overall our results suggest that populations of squirrel tree frogs may be adversely affected by modest increases in salinity; consequently, habitat salinization could present a threat to their reproductive success and survival.
