Meeting Abstract
The influence of environmental factors during sea turtle egg development makes the ongoing threat of climate change particularly worrisome. The nest environment greatly influences various aspects of sea turtle hatchling biology, including developmental rate and sexual differentiation. Sea turtles are considered particularly vulnerable to increasing temperatures because they have a cooler male/warmer female TSD system. Another climate change effect that receives less attention is changes in precipitation patterns. Changes in precipitation pattern, in conjunction with incubation temperature increases will alter nest conditions. This study experimentally examined the impact of increased moisture on loggerhead (Caretta caretta) hatchling sex ratios and hatching success across 3 nesting seasons nests. Experimental treatments received water in addition to ambient levels while control treatments did not. Sand moisture and nest temperature were measured throughout incubation. A sample of hatchlings from each nest was collected and their sex was verified. Nest moisture (rainfall as well as nest watering) correlated with sex ratios and hatching success. All treatments in all years had strongly female-biased sex ratios but there was higher male production in 2017 likely due to a large rainfall event in the beginning of the season. The impact of watering is largely dependent on ambient conditions with nest watering having very little impact on sex ratios when ambient temperatures are too high. Understanding rainfall and nest moisture effects are key to demographics, particularly hatchling sex ratios. This information will increase our understanding of the variation in, and drivers of, natural sex ratios and provide better predictions of climate change effects on loggerhead hatchlings.
